Horticulture

In a second replicated long-term field trial with ‘Valencia’ scion severely affected by HLB, highest yields over four harvests were with ‘US-942’ and ‘US-802’ root stocks. In both trials, some other root stocks that are commonly used in commercial production performed poorly, probably indicating less tolerance of those root stocks to HLB. Similarities and differences between the two trials will be discussed, as well as the value of different metrics for assessment of relative field tolerance of root stocks to infection by Las. The implications of these observations for the choice of root stocks to be used in commercial plantings will also be discussed. Interactions between plants and their associated microbial communities are complex, dynamic, and of varying impact. These interactions include plant-microbe and microbe-microbe relationships for each member of the community and can vary from positive to negative on each species. The structure of these communities can alter plant defense against other microbes and herbivores, plant productivity, and uptake of nutrients. Given these impacts, it is of interest to characterize the variation in microbial communities associated with crops facing major disease. The most devastating disease of Citrus is Huanglongbing caused by infection with at least one of Candidatus Liberibacter asiaticus, C. L. americanus, or C. L. africanus. Current methods of disease control involve disease vector suppression through conventional and bio-control methods, detection of infected trees, and inoculum removal.

Despite the success in slowing disease spread,growing strawberrries hydroponically these methods haven’t stopped the spread of disease. Methods to inhibit pathogen invasion may involve manipulations of microbial communities. In preparation for manipulative experiments, the microbial community of Citrus was characterized using 16S amplicon sequencing. Samples were collected from multiple locations within Florida, Texas, and California and consisted of trees cultivated using conventional and organic methods. Leaf midribs, fibrous roots, and soil were collected from trees infected with and trees with no detectable C. L. asiaticus. Results are discussed in terms of their impact on future microbial community manipulation experiments as well as their impact on disease detection. Liberibacter infection and tissue specificity. Several of these transcripts were selected as bait to detect protein-protein interactions using the yeast-2 hybrid system. Results indicate that transcripts involved in the immune response, endocytosis, and cytoskeleton assembly are important to Ca. Liberibacter infection of the psyllid host and/or in psyllid-mediated Ca. Liberibacter transmission. Ca. Liberibacter asiaticus is the obligate, fastidious bacterial pathogen that causes citrus greening disease, or Huanglongbing. CLas is transmitted in a circulative, propagative manner by Asian citrus psyllid Diaphorina citri Kuwayama adults. Identification and functional characterization of effectors involved in invasion of the psyllid gut and its presumed entry into the salivary glands was investigated using transcriptomic, proteomic, yeast-2 hybrid and coimmunoprecipitation analyses. In silico annotation and differential expression analysis of contigs from ACP nymphs and adults, and adult midgut and salivary gland tissues identified transcripts and proteins with altered expression in response to CLas infection. Several differentially expressed transcripts were selected and used as bait for Y2H detection of protein-protein interactions.

Those positive by Y2H were subjected to verification by bait to prey co-transformation and CoIP. Proteins positive in one or both assays were tested in ‘knock down’ experiments using dsRNA to induced RNA-interference and quantified by qPCR. Candidates of the greatest interest have been those with a predicted role in virulence and invasion, that if disrupted by RNAi could abate CLas accumulation in and exit from the gut, circulation in hemolymph and systemic infection, and acquisition e.g. in salivary glands. Collectively, the results suggest a model for invasion in which CLas- and prophage-encoded effectors transform the endocytic host pathway into a ‘pathogen-mediated phagocytic scenario’ utilizing membrane ruffling in CLas interactions with the gut, leading to bacterial exit into the hemocoel and systemic invasion of other psyllid host tissues and organs. Ca. Liberibacter asiaticus and solanacterum are the causal agents of Huanglongbing and Zebra chip disease of citrus and solanaceous crops, respectively. Bacterial effectors that interact with psyllid vector proteins during invasion of and exit from the gut, and that facilitate entry into the salivary glands were identified using functional genomics, proteomics, yeast-2 hybrid , co-immuno precipitation , and electron microscopic analyses. In silico annotation and differential expression studies of psyllid nymphs and adults, and midgut and salivary glands identified transcripts and proteins with altered expression in response to Ca. Liberibacter infection. Differentially expressed transcripts were used as bait in Y2H studies to corroborate protein-protein interactions. Those positive by Y2H were subjected to verification by bait to prey co-transformation and Co-IP. Electron micrographs of the PoP midgut revealed the presence of CLso in the ventricular lumen, apical and basal epithelial cytosol, and in the filter chamber periventricular space.

CLso were also prevalent in salivary gland pericellular spaces and head epidermal cell cytosol. Collectively, the results suggest a model for invasion in which Ca. Liberibacter- and prophage-encoded effectors manipulate the endocytic host pathway into a ‘pathogen-mediated phagocytosis scenario’ leading to bacterial exit from the gut into the hemocoel, and systemic invasion of other psyllid host tissues and organs. Beyond the devastating effects of HLB on tree health and crop size are the secondary impacts of preharvest fruit drop and the quality degrading flavor profile of symptomatic fruit. A precise number for the increasing percentage of the smaller, symptomatic fruit being sent to processors for juice extraction is not readily available. But inspection of data provided by NASS does indicate the number of fruits per box has been trending higher over the last five seasons. As previously noted increasing disease severity will increase the percentage of symptomatic fruit being used for juice extraction. In a 2015 survey of growers, production managers and other associated occupations 81% of the responders reported that 80% – 100% of their acreage was infected and the average percent of infected trees was 90%. As more and more fruit become symptomatic their detrimental effect on juice quality will become more and more pronounced. Beyond a blending ratio of 3:1 off-flavors in the product become discernible. The incidence of pre-harvest fruit drop also has been increasing with a recently reported 10% – 20% rise. Enabling a technology to utilize these two groups of HLB damaged fruit and recover lost value would be beneficial to the citrus industry during this transition period before resistant trees are available, especially if that technology also could provide increased value for all juice extracted biomass. Here we report on a pilot-scale continuous process to release and recover multiple value added co-products from culled fruit, preharvest dropped fruit and juice extracted biomass. Using steam-explosion followed by a simple water wash we have been able to recover pectic hydrocolloids, bioactive phenolics and fermentable sugars.Pectic hydrocolloids are functional polysaccharides that can be used to modify the rheology of water and as a hydration control or ion capture agent. Citrus phenolics contain a number of compounds that possess bioactivity against chronic human illnesses. Sugars can serve as a feed stock for a variety of synthetic options as well as an energy source in varied fermentation schemes. Limonene has a variety of established commercial applications. Summing these potential co-products could promote the dropped or flavor degrading fruits as an alternative value added resource and recover increased value from juice extracted biomass vs. a traditional feed mill operation.Huanglongbing constitutes the most destructive disease of citrus worldwide,rolling bench yet no established efficient management measures exist for it. Brassinosteroids, a family of plant steroidal compounds, are essential for plant growth, development and stress tolerance. As a possible control strategy for HLB, epibrassinolide was applied to as a foliar spray to citrus plants infected with the causal agent of HLB, ‘Candidatus Liberibacter asiaticus’. The bacterial titers were reduced after treatment with epibrassinolide under both greenhouse and field conditions but were stronger in the greenhouse. Known defense genes were induced in leaves by epibrassinolide. With the SuperSAGE technology combined with next generation sequencing, induction of genes known to be associated with defense response to bacteria and hormone transduction pathways were identified.

The results demonstrate that epibrassinolide may provide a useful tool for the management of HLB. Tamarixia radiateestablished and spread throughout Florida following first release in 1999 for control of the Asian citrus psyllid Diaphorina citri . Nevertheless, persistence of the pest and continued losses from citrus greening disease have created the need for more effective biological control, including mass rearing and augmentative release of T. radiata. However, information is lacking on ways to manipulate host density to optimize rearing efficiency. Three release rates of D. citri per shoot, and four host: T. radiate ratios were evaluated. Results indicated that 20 psyllid adults per flush provided optimal host density without excessive stickiness from honeydew. Sixty T. radiate females per cage of approximately 4,800 nymphs provided most economical use of wasps and hosts. However, only 60% of the hosts were utilized for progeny production under these conditions, possibly due to competition between females mediated through deterrent host marking. In order to determine the existence of a host mark on parasitized hosts, a three-day-old T. radiate females was released in a petri dish with six parasitized hosts and six clean hosts randomly distributed on an orange jasmine shoot. The number of hosts probed and parasitized in each host category was noted. To evaluate volatility of the host mark, 10 parasitized 4th instar D. citri nymphs and 10 clean nymphs were randomly assigned to one of the arms of the T- maize olfactometer. Ten T. radiate females were released at the releasing chamber to make a choice of the two odor sources. Results showed that T. radiate females probed and parasitized significantly more on the clean hosts versus parasitized hosts but showed no a preference for either of the odor sources. Thus, T. radiate females were able to discriminate between clean hosts and host parasitized by herself by perceiving a non-volatile host mark. Future research will focus on determining whether the mark also has a deterrent effect on nearby hosts. The ultimate goal is to improve mass rearing efficiency and biocontrol effectiveness in the field. Candidatus Liberibacter asiaticus is the bacteria associated with the economically-important citrus disease, Huanglongbing . Understanding the pathogenicity of CLas and its effects on the citrus host is challenging, as CLas has yet to be cultured. To understand the impact of CLas infection on host leaf metabolism, Parent Washington Navel orange Osbeck greenhouse plants were graft-inoculated with CLas+ or CLas- budwood, and leaf samples were collected longitudinally until tree death. Samples were analyzed with metabolomics , transcriptomics , and proteomics to identify CLas-associated changes in the plant. Changes in metabolite content could be observed as soon as 6 weeks post-infection, before symptom development. Further changes in the metabolome, transcriptome, and proteome were observed throughout the study, with the most drastic differences noted at the last time point as the trees were nearing death. CLas affected both primary and secondary metabolism, including photosynthetic processes, cell wall synthesis, and stress responses. These data show that early changes in tree metabolism occur in asymptomatic plants with CLas infection, and shed light on how CLas impacts the citrus host throughout the disease. The concept of growing degree-day , which integrates the rate of development of an organism as a linear function of air temperature to which it is exposed, has been widely used in studies of crop and insect phenology for scheduling agricultural practices. In citrus, however, these studies have focused on the reproductive development and on the physicochemical characteristics of the fruits but not on vegetative shoot ontogeny. This is important because vegetative shoots are strictly linked to the biological performance of Diaphorina citri. Although the thermal requirements of the psyllid have been established in growth chambers, little is known about the thermal requirements for the psyllid in natural environments or about the cumulative heat units for the emission and development of new shoots, taking into consideration their ontogeny. To assess this, experiments were carried out in growth chambers using 2.5 year-old potted ‘Valencia’ orange grafted on ‘Swingle’ citrumelo. The plants were pruned 20–30 cm above the grafting line and evaluated for several flushing cycles. Daily assessments of shoot size, new leaf emergence and leaf area were carried out on a single shoot per plant.

Local governments readily looked to these studies to justify new programs and initiatives to support efforts to address food access issues locally. And yet, some researchers were more concerned with the conceptual basis of the term ‘food desert,’ which failed to account for the ways that poor communities have managed to cope in spite of grocery stores or supermarkets. For example, some argued that areas defined as food deserts in fact are replete with smaller food retailers, which contribute to food security and may present future opportunities to do so . Others—particularly the mass media—also questioned the still inconclusive connection between the development of supermarkets and improved health outcomes.Overall, food desert research made a strong public health case for developing new grocery stores in under served communities, despite sometimes conflicting, and inconclusive evidence. As community-based food projects continued to expand through the early 2000s, a new generation of food activists sought to reframe the community food security movement to encompass social justice, human rights, and economic self-reliance through food systems . Inspired by international peasant farmers and environmental justice movements, “food justice” activists approached food access issues through programs and entrepreneurial activities focused on engaging disenfranchised populations in directly revitalizing their communities.

As such, ‘food justice’ is more squarely premised in “ensuring the benefits and risks of where,hydroponic growing what and how food is grown and produced, transported and distributed and accessed and eaten are shared fairly .” Frequently cited examples of the distinctive “food justice approach” include People’s Grocery in West Oakland and Growing Power in Milwaukee. People’s Grocery was established in 2002 with the goal of “build[ing] a local food system that improves the health and economy of West Oakland” . Its foundational programs comprised a youth-run community garden, nutrition education programs, Community-Supported-Agriculture, and a mobile grocery market—all pursued with the ultimate goal of developing a grocery store in West Oakland. Although this program was discontinued in 2009, a for-profit subsidiary of People’s Grocery is developing plans and securing financing for a new grocery store in West Oakland. Established in 1993 by former professional basketball player, Will Allen, Growing Power is an organization that whose mission is “to grow food, to grow minds and to grow community” . Initially focused on vermiculture and aquaponics, the organization has expanded to include a community center, grocery store, and fourteen greenhouses in both Milwaukee and Chicago. These models of “food justice” have been readily replicated across the country, with a distinct focus on connecting food production and retail to serve broader community goals. Organizations such as People’s Grocery also define their work explicitly as a response to food deserts. Alongside of these activities, Philadelphia-based CDFI, The Reinvestment Fund initiated the Pennsylvania Fresh Food Financing Initiative , the first statewide financing program specifically designed to attract supermarkets and grocery stores to under served urban and rural communities. The program was established in 2004 through a public-private partnership between non-profit organization, The Food Trust and The Reinvestment Fund following dissemination of a 2001 report “Food For Every Child: The Need for More Supermarkets in Philadelphia” confirmed the findings of other studies of food deserts.

As a response to the findings, the Philadelphia City Council convened a task force, which recommended the creation of a statewide initiative focused on incentivizing grocery store development. Eventually in 2004, state representatives and then Governor Ed Rendell enacted an economic stimulus package, which allocated $30 million for the creation of the FFFI. The Reinvestment Fund then leveraged another $120 million through the New Markets Tax Credits program and private banks . Since its inception, the program has offered grants of up to $250,000 and loans ranging from $25,000 to $7.5 million primarily to independent, locally owned businesses including green grocers, food cooperatives, and full-service supermarkets. These grants and loans primarily support predevelopment, acquisition, equipment, construction costs, start-up costs, and employee recruitment/training . As of June 2010, the FFFI financed 88 grocery stores comprising $73.2 million in loans and $12.1 million in grants . Overall, community food security movements combined with the growing body of research on food deserts represented the beginnings of a strong public health agenda around the development of grocery stores in low-income communities and communities of color.And yet the limitations of this early research began to exhibit the very complexity of food access issues in low-income communities of color understated by the simplicity of the term food deserts. Still the emergent public health voice around food deserts served to reinvigorate old discussions about the urban grocery gap to new ends. Accordingly, the “metaphor” of the ‘food desert’ provoked both a community-based and local government response, which marked the beginnings of an expanded set of social and economic goals around grocery development as evident in today’s context. By the late 2000s, food deserts captured the attention of researchers, journalists, policymakers, the grocery industry, and the general public. food deserts would enter into federal policy agendas provoking a new set of research and local accounts calling the basis of food deserts into question. And yet, despite debates over the characterization of supermarkets as a proxy for “healthy food access,” grocery stores would form the basis for the federal program devoted entirely to the subsidization of grocery stores in under served areas.

The momentum around food deserts in late 1990s to mid 2000s reached a critical point with the 2009 USDA-sponsored national survey, “Access to Affordable and Nutritious Food: Measuring and Understanding Food Deserts and Their Consequences.” Congress commissioned the study as part of the 2008 Food, Conservation, and Energy Act . In contrast to previous studies, this study was the first ever, national assessment of food deserts . Over the course of one-year, the USDA worked in collaboration with the National Poverty Center at the University of Michigan and the Institute of Medicine of the National Academies for U.S. Census data analysis, interviews, and focus groups. Furthermore, the study found that further research was necessarily “to conclusively determine whether some areas with limited access have inadequate access” . Despite the mixed findings, the authors strongly recommended policies and programs to expand healthy food access in under served communities. This includes: 1) incentive programs to attract new stores and improving existing ones , 2) community-based programs such as corner store conversion, 3) transportation improvements to make supermarket access easier and more affordable, 4) policies that specify healthy food offerings fore retailers authorized to participate in the SNAP program, and 5) the integration of grocery planning with housing and community development. Months prior to the release of the report, Oakland-based think tank, PolicyLink, The Reinvestment Fund, and The Food Trust began working with the Office of the White House to develop a national version of the Pennsylvania FFFI. The release of the USDA study was further affirmation of their efforts. In months following, a series of initiatives laid the groundwork for a comprehensive federal program to address food deserts nationally. The USDA study would provide the evidence base for a “Food Environment Atlas,” an online national food desert locator, designed to identify counties with limited supermarket access. The USDA created the tool specifically to locate priority areas for future interventions. The development of this online tool coincided with the instatement of Let’s Move,mobile vertical farm national childhood obesity prevention campaign launched by First Lady Michelle Obama in early February 2010. In the year that followed, HFFI administered its first cycle of grants to sixteen organizations across the country for initiatives ranging from CDC-chain supermarket partnerships, farmers markets, and business incubation programs . The HFFI inspired newly elected Chicago mayor, Rahm Emanuel convene a ‘Food Desert Summit’ to meet with major grocery retailers to discuss a plan for eliminating food deserts. Soon following in July 2011, the First Lady hosted her own summit with major food retailers, where she secured commitments for store expansion from Supervalu,Walgreens, Walmart, and regional retailers. Together, the retailers agreed to newly develop or expand 1500 stores over a five-year period. Additionally, the First Lady’s summit resulted in the creation of California-based counterpart of the Pennsylvania FFFI, the California Fresh Works Fund. A project of statewide health foundation The California Endowment, the $200 million public-private partnership was created to finance a variety of “healthy food retailing” initiatives . Several subsequent studies further reinforced these critiques. A controversial longitudinal study in the Archives of Internal Medicine questioned the connection between food environments and diet quality . Over a 15-year period, researchers monitored eating habits of thousands of residents in four cities. The study found that proximity to fast food retailers increases the risk for poor dietary quality and obesity .

And yet, proximity to supermarkets did not impact fruit and vegetable consumption . Ultimately, the researchers conclude that supermarkets may not be enough to change unhealthy diets. And yet, a string of subsequent studies similarly refuted the idea that obesity could be combatted through grocery development. A 2012 study by the Public Policy Institute of California found that poor neighborhoods were not all food deserts. While some tended to have a higher concentration of liquor stores and fast food restaurants , others also tended to have a larger concentration of grocery retailers compared to suburban areas . In line with the previous study, this was among research that suggested no correlation between supermarket proximity and dietary patterns . These studies were subject to their own critiques, in part due to the differences in the study populations—be it low income men , children , or young adults . Despite competing claims regarding the efficacy of supermarkets in addressing obesity, grocery retailers have been reentering urban areas for the past decade, with more incentives than ever. Several retailers have created “urban format” stores, such as Walmart Neighborhood Market, Fresh and Easy , and Tesco Express. Community-based organizations have continued to seek out alternatives to these types of stores be it through farmers markets and/or cooperatives. Accurate and high-throughput protein quantification is fundamental to proteomic studies . To provide the highest quantification accuracy when comparing samples one needs to minimize differences introduced in the processing of samples and acquiring the data. This can be best achieved through the introduction of stable isotopes into samples that allow samples to be mixed and then analyzed in the mass spectrometer. The application of metabolic labeling, which uses stable-isotope labeled amino acids in cell culture or 15N nitrogen-containing salts into the whole cell or organism in vivo, enables relative quantifications of proteins on a global scale. In such a quantitative experiment, one sample is labeled with the natural abundance , and the other with a stable isotope of low natural abundance during growth. The samples are mixed, processed, and analyzed by the mass spectrometer. Chemically identical peptides from these light- and heavy-labeled mixed samples co-elute by chromatography into the mass spectrometer, which can distinguish between the light and heavy peptides based on their mass difference, and thereby quantify the difference in peptide, and hence protein abundance between the samples. An alternative stable isotope-based strategy is to chemically tag peptides after enzymatic digestion; the most popular reagents for this strategy are isobaric tagging reagents Tandem Mass Tags . The TMT isobaric tagging reagents allow comparison of a larger number of samples, but the labeling is done at the peptide level after sample digestion and then samples are mixed. In contrast, the metabolic labeling is introduced into the proteins during growth, thus samples can be combined at the beginning, minimizing variations introduced by sample processing that can compromise quantification accuracy . Although SILAC has been widely used in animal cell lines and has been the gold standard for MS-based proteomics quantification , 15N-labeling based quantitative applications are still quite limited in plants despite it being cheaper . This could be due to the complexity of the data analysis. SILAC pairs are easily identifiable because they have well-defined mass differences as typically only lysine and arginine are labeled. In contrast, in 15N labeling, each amino acid in the expressed proteins is labeled, and therefore, the mass difference in 15N pairs varies depending on the number of nitrogen atoms in their composition.

Accordingly, many of the Master’s gardens employed thematics associated with the labyrinth and the grotto; of hiding and revealing, of voyeurism, exotica, minutiae, and narrative . In the descriptions that follow, I roughly corral the nine Masters’ Gardens into three categories; labyrinths, rooms, and representative gardens. Using this draft rubric, I explore three Masters Gardens in detail, three at a more cursory level, and the remaining three in passing. My choices in this regard certainly reflect a hierarchy of my experiential and theoretical impressions of particular gardens.Of the labyrinthine-type gardens, the Maze Garden by Martha Schwartz Partners is the most overtly fabricated . Comprising a set of high walls incised transversely by equally spaced arched passages, the garden presents itself as an open labyrinth. In this regard the sensation of moving amongst the array of walls and apertures is reminiscent of Eisenman’s Holocaust Memorial design, where the object is perhaps to test Walter Benjamin’s edict that we must have approached and left a place by all four cardinal directions to truly know it.But this effect is quickly subverted; firstly, the grove of willow trees that supplies a canopy over the garden is forever offered but seemingly never substantiated as the trees themselves remain evasively encapsulated within chambers between wall sets. Secondly, the alignments of the garden walls perform a cunning rotation which serves to subtly disorient the visitor and provide niches for actuating the third effect: self-reflection.

At the entrance to the labyrinth, a freestanding wall is clad on one side with dark mirrors. Like a magician showing the audience an empty hat before drawing out a rabbit,vertical grow rack these mirrors purport to be as they appear; a harmless arena for mass self-vanity.Moving into the walled matrix, we are habituated to more dark mirrors at the end of each elongated space. Further still, as the geometry rotates and tapers, mirrored chambers are increasingly encountered, some small, some large. One threshold further discloses a penultimate roofed cavern. Here, a grove of willows is finally revealed, albeit through deeply hued glass which serves to obfuscate the demarcation between the real and the represented. But this is not the final revelation, which is delivered as one follows the cavern around to the exit. From this privileged position of hindsight, we are placed behind the looking glass and discover that the mirrors throughout the garden are one-way glass. At the largest interfaces—attracted like moths to a lamp—entire groups of people gaze innocently at their reflections. In the smallest chambers, young couples make use of their mistakenly private niches and engage in intimate embraces, unaware of the public viewing gallery beyond the glass. As unwitting participants in a social experiment, visitors have been lured into carefully orchestrated traps using human vanity as bait.In this context, the disorienting walled maze and hall of mirrors trade light-heartedly in the excitement that we derive from ‘getting lost, of finding a way back, and ultimately a way out or to a goal’. However, mazes operate through turning pleasure seamlessly into confusion so beneath this playfulness lays a disturbing metaphor in the infernal prospect of there being no goal or exit. Within this context, the open labyrinth model upon which the Maze Garden is based reflects an increasingly complex contemporary life-path where we expect a maze to harbor choices, divergences and dead ends. In contrast—as if tracking a fatalistic passage through life—labyrinths were historically manifested more as a single route spiraling inward to a central goal and then back outward to reconnect with the point of origin. The Garden of Bridges by West 8 takes this motif of the single path and entangles it as a Gordian Knot . In the place of walls, the garden uses the same bamboo employed in the frame to inundate the site.

Into this dense forest is incised a single narrow trail, which continually twists and turns back, affording occasional glimpses of other people elsewhere on the same path. In instances where the path loops over itself, implanted bright red arching bridges enable grade-separated passage. When immersed in the bamboo everything is close at hand and body based; as Robert Harbison observes, we allow plants to confine us in ways that would be unpalatable in stone.Gaston Bachelard conveyed the sense of immensity that the forest imparts, noting that this bodily impression openly contradicts geographical reality. 18 Similarly, Yi-Fu Tuan concurs that even if small, the forest gives the appearance of being limitless when we are lost within it. At just 10 000 sq ft, The Garden of Bridges is saturated with this effect, with the notable digression of occasional respite in the form of the bridges. As we climb up and emerge above the canopy with a clear overview, vision takes over as we strive to take our bearings by reasserting general orientation amongst the landmarks of the Expo site before descending back down into the thicket. The deceit is that the bridges represent false ‘pyramids of reason’ within the labyrinthine forest, since the path below is always obscured, meaning that the overview is useful neither for reconciling one’s journey thus far, nor reconnoitering the future route. We can see our companion at the top of another red bridge, but cannot tell whether to head forwards or backwards to get to them. Instead, we rely on a combination of dead-reckoning recall and faith in the universal consistency of Cartesian space; earlier, we walked ahead of our accomplice, so therefore, they cannot be in front of us now. On a single path, to avoid getting lost no matter how geometrically complex, we need only to keep a record of where we came from in differentiation to where we are headed—a tough ask when the empirical world of entangled bamboo and bridges says otherwise. Where the Garden of Bridges fills the frame to generate the effect of the thicket, the Big Dig garden by Topotek 1 uses the opposite tactic of a frame opened on one side and an empty field to present the surface of the garden plot in its entirety to passers-by .

A parabolic hole at the centre of the site is calibrated so that the bottom is never revealed; the void becomes in effect vertiginous and infinite. The illusion of tunneling through the mantle toward the other side of the world is manifested instead as a collaged soundscape, so that sounds of other cities and landscapes emanate from the depths. The effect invokes Buckminster Fuller’s observation of changes in perceptions of spatial relations as a result of the aerial warfare of WWII, on which he noted that ‘the world has been surprising itself by coming in its own back doors and down its own chimneys from every unlooked-for direction’. This act of tunneling takes perceptions that originate from afar and incises them into the composition of local space, producing as Brian Massumi notes, ‘a fusional tension between the close at hand and the far removed’. In the ultimate local-global exchange, ‘as the distant cuts in,vertical planting tower the local folds out’.The garden is reminiscent of Bernard Lassus’s 1970s bottomless Well design concepts, which proposed a deep vertical shaft into which stones could be thrown to infinity. These speculations explored the psychological space of depth; not in terms of the abyss that reveals the feared absence of foundations,but rather, as a refuge for the imagination in a world without uncharted spaces for the mind. As Lassus notes, with the complete mapping of the surface of the earth in the age of exploration erased the terrestrial or horizontal frontier. A replacement frontier came in the conquest of the ‘immeasurable verticals’, culminating in the first moon landing. As a counterbalance to these giddy heights, Lassus invests poetically in a depth beneath the surface that we tread on, also ‘immeasurable, vertical and obscure’.Stephen Bann interprets this to mean that garden design should involve the ‘poetic creation of depths’. Whether indirectly invoked or actually constructed, Bann sees a landscape of depths as the creative balance to ‘an increasingly strong preoccupation with the vertical dimension’. It is as filling the holes left by archaeology will re-balance the cosmically distant with the terrestrially deep, stabilizing landscape’s regular field of operations, the surface itself. Topotek’s scheme trades not in poetic depth as a counterbalance as per Lassus but rather in didactic depth. For Lassus ‘dropped pebbles travel forever’,thus fabricating the illusion of the terra incognita that the world lost when it ‘closed the map’. For Topotek’s ReinCano on the other hand, the pebble metaphorically returns, with compound interest, from the other side of the noisy and full world. Indeed, as Bann notes ‘the last white patches have vanished from the map of the world’ because ‘China has finally lost its monstrous otherness and become a Mecca for tourists’.Fittingly located in China, the Big Dig is like the last tiny residue pin-hole of this filled up map. But it is a false holdout, since—like an intrepid climber who scales a Swiss mountain only to discover a restaurant perched on the summit—others are already present, having taken a convenient shortcut.

Unlike Lassus, in this hole there is no depth, only more surface, since every hole has a lining; ‘the hole lining is the hole’. Indeed, if we ignore the inconvenient balustrading around the hole and focus on the surface, the parabolic fall-away becomes a Pierce’s Puzzle, which confounds what is the hole and what is not. Are we— like the caged fox that decides it is free while the rest of the world is incarcerated—actually already in the hole without realizing it?The room-type gardens fall into two sub-categories; cloister-like rooms operating as islands within the garden, and open plan rooms spanning the width of the garden. Passages Garden by Terragram falls into the latter category, using the wall as a spatial calibration device . A stone path that leads in to the garden cuts through several walls at oblique angles before disintegrating down into a body of water. Ahead, a low aperture in a bright orange wall allows glimpses of the paving stones re-integrating from the water to reform the path. Water seeps from a fissure that runs the length of the battered back retaining wall, refreshing the pond and heightening the sensation of being in a situation that is in tension and flux. With the impassable aperture preventing egress to the recomposed path, visitors strike out across an expanse of white river stones peppered with diminutive pine trees. Here, at an opening in the other end of the orange wall, a single smooth rock levitates precariously at eye level, the gravity field of its copious weight appearing to deflect the overhead beam. In Chinese garden tradition, stones hold a special meaning and allure; like a talisman, this rock the place to which visitors are drawn, to paw at the marbled surface, realign it around its pivot, and to contemplate its meaning. The circular cloister at the heart the Botanist’s Garden by Gross.Max operates as a retreat deep within the garden . Constructed from tightly stacked roof tiles, the wall forming a Hortus Contemplationis is battered at an angle reminiscent of the ancient city walls encasing Xi’an. This geometry, combined with the bulk of the wall neutralizes the cacophony of the Expo. The garden planting seems innocuous at first, but in time a second layer of delicate exotic botanica comes in to focus. Whereas elsewhere in the Expo, monocultures of floral displays are measured in hectares, within this botanical heterotopia, species are indulged one specimen at a time. Of a similar scale, the Quadrangle Garden by Atelier DYJG employs the repetition of four rooms that have been deflected from rectangles. However, unlike the Botanist’s Garden cloister, which by virtue of the mass of the wall is oriented wholly internally and vertically, complex apertures in the walls of the quadrangle rooms provide for a kaleidoscope of fragmentary glimpses of scenes in the surrounding garden.Of the three gardens that overtly represented other landscapes, two embodied more mythical landscape types while the other embodied a nation-state. On the latter, whereas many of the non-architected exhibits at the Expo attempted to represent a particular province, the Landscape Garden by Mosbach Paysagistes gathered all of China into its representational net.

Studies of PTI have focused on the bacterial peptides flagellin and EF-Tu and their action in Arabidopsis. These peptides are perceived by PRRs, receptor-like kinases that are crucial for perception of flagellin/EF-Tu and activation of PTI. However, unlike flagellin and EF-Tu, many of the historical elicitors that stimulate well-characterized defense responses in plants have not been sufficiently investigated to resolve their modes of action . The elicitors AA and EPA conform to the definition of MAMPs: they are not present in higher plants, are essential components in oomycete cells, are largely absent from other classes of microbes, and elicit similar defense responses in plant species where they have been studied . Eicosapolyenoic acid elicitor activity in plants was first discovered in the interaction between Phytophthora infestans and potato. Mycelial extracts of P. infestans induced sesquiterpenoid phytoalexins, lignin deposition and cell death in potato tissue in a reaction similar to a HR to incompatible races of the pathogen. Purification and analysis of all active fractions in these extracts identified AA and EPA, without exception, either free or esterified to other molecules .

Elicitation was specific to AA and EPA. Treatment with 15 other fatty acids, including LA and ALA ,mobile vertical grow racks the primary unsaturated fatty acids found in higher plants , as well as structurally similar eicosatrienoic acid and arachidonyl alcohol, did not elicit defense responses. Treatment of tuber disks with AA also protected them from subsequent P. infestans infection .Eicosapolyenoic acids induce systemic resistance in potato as well as in other plant species to various pathogens. Although the mechanisms remain unresolved, EP have been shown to elicit SA, JA, and ET in different experimental systems. Colonization of avocado seedling roots by P. cinnamomi was reduced in roots treated with AA prior to inoculation . Pearl millet seedlings were protected to a greater degree against infection by the downy mildew pathogen, Sclerospora graminicola, following seed treatment with AA or EPA, in contrast to seedlings emerging from seeds treated with LA, ALA, DHA or water . EP elicit SAR or SAR-like responses in tobacco, potato, and tomato. Treatment of lower leaves of tobacco plants with AA induced local and SAR to TMV . EP treatment of the lower leaves of potato plants protected the upper leaves from infection by P. infestans, a systemic resistance that developed within 5 days of the inducing treatment . Plants treated with LA, ALA, or oleic acid displayed partial protection but not to the level of EP-treated plants. AA also induced resistance in potato leaves to the early blight pathogen, Alternaria solani, with levels of SA and a PR1-like protein elevated in the AA-treated leaves . AA-treatment of tomato leaves induced localized accumulation of transcripts for P4 , a PR-1 family member and SAR marker in tomato , but did not induce expression of the proteinase inhibitor gene PI-2. The latter is strongly induced by wounding and JA treatment and serves as a marker for JA-mediated resistance in tomato . Although the studies in tobacco, potato, and tomato indicate that EP-induced resistance may operate through SA, recent research suggests EP action is more complex .

Treatment of tomato and Arabidopsis leaves with AA increased JA levels, reduced SA levels, and increased resistance to Botrytis cinerea. Arabidopsis plants transformed to produce small amounts of EPs were less susceptible to P. capsici, B. cinerea, and feeding by aphids. However, these plants were more susceptible to Pseudomonas syringae pv. tomato . The EP plants had constitutively elevated levels of JA and JAmarker gene expression and reduced levels of SA and SA-marker gene expression relative to wild-type plants. The differential effect of EP on disease and pest outcomes corresponds to EP’s impact on SA and JA defense signaling, and this effect is dependent upon JA as demonstrated with a JA-deficient aos mutant line . Salicylic acid and JA can be mutually antagonistic , making it difficult to reconcile these different findings. AA treatment elicits ET production in both pepper and potato , and ET can modulate SA- and JA-defense networks . The different experimental outcomes may result in part from differences in EP concentrations used in the various studies. Higher concentrations of EP can induce an intense, localized necrosis at the site of application, particularly in solanaceous plants. This strong phenotype could trigger or result from phytohormone changes different from those induced by low concentrations. Also, it is possible that all three phytohormones are important in establishing EP-induced resistance through a process of transitional signaling . A study in potato indicates that both SA and JA are important in PTI responses , and a study of PTI in Arabidopsis using signal allocation analysis of mutants deficient in ET, SA, and JA signaling indicated that PTI depends on synergy among ET, SA, and JA . Further research is needed to fully elucidate the interactions among SA, JA, and ET in their involvement in EP-induced resistance and defense responses.Eicosapolyenoic acids have been useful in dissecting aspects of secondary metabolism in plants, with a focus on sesquiterpenoid phytoalexins in solanaceous plants. However, EP elicits production of defense metabolites in other plant families as well. The isoflavanoid phytoalexins phaseollin and coumestrol accumulate in leaves of French bean following infiltration with AA . Phenol-2,4-bis , a defense compound in avocado, is induced in roots treated with AA as well as with SA .

Among solanaceous plants EP elicit sesquiterpenoid phytoalexin synthesis in thornapple, eggplant, chili pepper, green pepper, potato, and tomato . In potato tuber, AA elicits sesquiterpenoid phytoalexin biosynthesis with strong expression of sesquiterpene cyclase, a committed step in the pathway. Concurrent with this is a complete suppression of wound-induced squalene synthase and steroid glycoalkaloid accumulation . HMGR catalyzes the first step in the synthesis of stress-induced isoprenoids from mevalonate in potato. Three isoforms of HMGR are differentially induced by wounding and AA treatment , and a similar expression pattern of the corresponding HMGR isoforms occurs in tomato .In addition to potato, EP have been shown to elicit PCD, characteristic of the HR, in other plant species. Pearl millet seedlings treated with AA displayed a HR similar to that induced by the oomycete, S. graminicola, the causal agent of downy mildew. Following treatment with AA, the HR developed more quickly in pearl millet seedlings with genotypes rated as resistant versus susceptible to S. graminicola . Tomato protoplasts treated with AA underwent PCD with characteristic DNA fragmentation and laddering, while LA and ALA treatment had no PCD-inducing effects . In both potato and pepper, AA was found to induce ROS in a similar manner. AA treatment of potato tuber disks elicited a biphasic oxidative burst peaking at 1 and 6–9 h after treatment and increased expression of StRBOHB, a homolog of gp91, which encodes a subunit within the neutrophil NADPH oxidase complex . As in potato, treatment of pepper fruit with AA elicited an immediate, rapid ROS burst. When DPI, an inhibitor of NADPH-dependent oxidases, was applied to the fruit prior to application of AA, ROS generation decreased as the concentration of DPI was increased .The mode of action of EP in PTI is unresolved, although the structural requirements of EP as elicitors are well characterized. These include at least a 20 carbon backbone with all cis-1,4-pentadiene unsaturation beginning at the 5 position and at least four double bonds in the chain . While this specificity could provide evidence for involvement of a receptor that recognizes these structural features,vertical garden growing previous studies of EP in potato indicate that initial perception by plant cells may be quite different than other MAMPs. Initial recognition of AA and EPA may occur by specific disruption of host membrane integrity and/or perturbation of oxylipin metabolism, with the possibility that plant cells produce novel oxylipins from EP . Studies in potato showed that U-14C radiolabeled AA was quickly incorporated into neutral lipids and polar lipids . A small fraction, ∼2–5% of the AA, was oxidized . Also, sporangia of P. infestans readily incorporated exogenous 14C-AA into phospholipids , diglycerides and TGs. By 12–14 h after inoculation, microautoradiographic studies revealed that the radioactivity from sporangia was released into the epidermal and palisade mesophyll cells adaxial to the inoculated leaf surface and distant from fungal structures . Plant phospholipases are activated following attack by pathogens or treatment of plants with elicitors . This could create an opportunity for any EP incorporated into plant lipids during infection to be released and accessible to plant oxylipin enzymes. Research in potato and tomato indicates that the 9-LOX pathway may play an important role in EP action. The first step in the enzymatic formation of phyto-oxylipins involves the action of LOX .

Plant LOXs act on PUFA containing a cis– pentadiene system, inserting an oxygen molecule to form hydroperoxy fatty acids. These are further metabolized to various oxylipin families by members of CYP74 cytochrome P450s: AOSs, HPLs, and DESs, or by less well-characterized POX or PXG and EASs . The importance of LOX, in particular a 9-LOX2, in EP elicitor activity is supported by fatty acid structure-activity requirements and studies of LOX expression. The carboxyl function of EP is critical, a feature consistent with the substrate requirement of plant LOXs . A 5 double bond at the beginning of a methylene-interrupted series with at least four double bonds provides the highest elicitor activity . AA stimulates LOX expression in potato and tomato , with 5-HPETE a principal LOX product formed after treatment of tissue with AA . Expression of pLOX1, a potato LOX gene now identified as a 9-LOX type 1 , was strongly induced in AA-treated and P. infestans-inoculated potato tuber disks and leaves , as was a tomato LOX in AA-treated tomato leaves . LA-treatment did not induce pLOX1 expression or LOX activity. Heat treatment of tuber disks inactivates enzyme activity and abolishes HPETE formation following AA treatment , and EP-induced responses are strongly diminished when LOX activity is inhibited or absent . Nonetheless, definitive experiments with LOX knock-out/knock-down or over expression lines to critically test specific LOX isoforms in EP action have not been reported. While it has been proposed and is quite likely that the 9-oxylipin pathway metabolites of AA may directly act as signal molecules to activate defense responses , AA and/or its metabolites may also induce expression and activity of oxylipin pathway enzymes to form biologically active metabolites from the plant LA and ALA pools. Studies during the past 15 years in solanaceous plants point to the importance of 9-LOX and the 9-oxylipin pathway in defense, and have demonstrated that the 9-LOXs from potato, tobacco, and pepper can utilize AA as a substrate. Many of these studies have investigated defense responses against oomycete pathogens or used elicitor preparations from oomycetes likely containing EP . 9-hydroperoxy fatty acids can be utilized by downstream oxylipin pathway enzymes to form other compounds that have been found to function in defense. In particular, DESs are induced in response to elicitors and pathogen attack in several solanaceous species including potato, tobacco, and pepper . DESs are CYP74D P450s that produce the divinyl ethers CA from 9-HPOD and CnA from 9-HPOT. Recent experiments indicate that treatment of tomato roots with EP induces resistance against P. capsici. Hydroponically grown tomato plants whose roots were treated with EP and subsequently inoculated with P. capsici experience significantly less rot and collapse at the crowns than plants whose roots were treated with H2O, LA, or ALA, indicating that exposure of tomato roots to EP prior to inoculation with P. capsici reduces susceptibility of the plants to P. capsici . Further experiments demonstrate that roots and crowns display significantly increased lignification responses following root treatment with AA and EPA and subsequent inoculation with P. capsici compared to roots treated with H2O, LA, and ALA. AA-treatment of tomato roots elicits increased expression of 9-LOX and 9-DES genes in tomato roots compared to control treatments . Expression of 9-DES is also increased following inoculation of roots with P. capsici . In conclusion, although EP action in plants is complicated, evidence supports an important role for LOX and likely a 9-oxylipin pathway in the initiation of plant responses. Furthermore, in Arabidopsis an intact JA pathway is required for AA activity, implicating a 13-LOX. Whether DES and divinyl ethers participate in the plant response to EP observed in solanaceous plants is unresolved, although ongoing research in our laboratory will address this issue.

Although we did not directly measure selection in this study, we used the large body of work on drought adaptation to infer the adaptive value of specific trait combinations. We predicted that due to the drought escape strategy conferred by derived loss of function mutations at FRI, accessions with these alleles would inhabit environments with consistently wetter growing seasons, relative to accessions with functional FRI alleles. To confirm the allelic association with drought, we generated a climate envelope for both FRI allele classes . Functional alleles tend to be present in areas with lower growing season precipitation than non-functional alleles. We have demonstrated that lines that diverged only at FRI exhibit altered positions along an adaptive phenotypic correlation. Scarcelli et al. found antagonism between the floral morphology traits affected by FRI, and we cannot rule out that a portion of FRI’s pleiotropic gene action is maladaptive. However, analyses presented here demonstrate a strong adaptive role of the physiological and phenological phenotypic correlations conferred by FRI. Given our results, it is not surprising that FRI is associated with strong population genetic signatures of diversifying selection. Studies demonstrating historical selection on FRI invoke the timing of flowering as the phenotype under selection. Our results indicate that the observed signature of selection is not only an effect of FT variation, but may also be due to upstream physiological effects.Stress caused by salinity is one of the most serious environmental factors, which inhibits plant growth and decreases crop productivity worldwide. Primary effects occurring at the beginning of salt stress include retarded cell division and expansion, stomata closure and photosynthesis reduction. During long-term exposure to salt stress, accumulation of salt ions in plant aerial parts via the transpiration stream leads to ionic stress. To adaptively respond and survive under salinity, plants require changes of various cellular, physiological and metabolic mechanisms, which are controlled by the regulated expression of specific stress-related genes through cascades of complex regulatory networks. Rice , one of the world’s most important cereal crops, is classified as a salinity sensitive crop. An electrical conductivity of ~ 6 dS m− 1 would result in more than 50% reduction in yield of many rice varieties. Therefore, plant breeders are continuously improving salt tolerant rice cultivars to increase yield productivity. However, salt tolerance is a multi-genic trait, which underlying mechanisms are controlled by many genes and affected by the environment. Breeding efforts for developing salt tolerant rice have been limited because the salt tolerance mechanisms and the genes that control them are not completely understood.

To fill the knowledge gap between genotypes and phenotypes of the salt stress response in rice,vertical planters for vegetables forward and reverse genetics have been performed to identify salt-responsive loci/genes such as genetic mapping of quantitative trait loci using cross population; screening of mutants generated by chemical- or irradiation-induced mutagenesis; and transgenic approach. To identify salt-responsive genes using cross population, a number of mapping studies have identified QTLs of physiological traits related to salinity tolerance in economic crops such as soybean, barley and rice. Although QTL mapping is a powerful and popular method to tag the salt tolerance region in plants, the examination of the variation is one of the limitation because QTL mapping can identify only allelic diversity that segregates between the parents of a particular F2 cross or within recombinant inbred lines and the mapping resolution is limited by the amount of the genetic recombination event occurring in the mapping populations. Moreover, the genotyping by SSR markers, which is usually based on polymerase chain reaction , is limiting to examining the kinds of variations, and laborious and time-consuming when high-density genotyping is needed for a large number of individuals. Over the past several years, next generation sequencing has been used to rapidly generate a large amount of accurate genomic data, providing a powerful approach for functional genomics and molecular breeding studies, including the genome-wide association study. GWAS, which is the analysis of the statistical association between genetic variants and traits on the whole genome scale in a large number of individuals within an organism, has been employed to identify causal genetic variability for target traits, including those in Arabidopsis and crop species. Compared with the QTL linkage mapping method, GWAS provides high resolution mapping using single nucleotide polymorphisms as genetic markers. GWAS in rice was performed for agronomic traits such as tiller number, grain width, grain length and spikelet number in the indica subspecies based on SNPs identified by whole-genome sequencing. In another report, the genetic architecture of rice chlorophyll content at the heading stage was revealed by GWAS.

Forty-six significant loci were identified and Ghd7 was highlighted as a major locus for the natural variation of the chlorophyll content. GWAS also revealed three QTLs located on chromosomes 3, 6 and 12 associated with the responsiveness of yield-determination traits under field condition. Application of GWAS for causative gene identification has been reported in rice responding to abiotic stresses such as aluminum, boron, cold, drought and salt stresses. On salt stress, there are several GWA studies in rice with different growing stages and traits. Shi et al.studies GWAS on germination stage of salt-treated rice using ~ 6000,000 SNPs, 11 loci containing 22 significant SNPs responsible for stress-susceptibility indices of the vigor index and germination time were identified. The strongest association region for germination time was detected on chromosome 1, near salt-tolerance QTL controlling Na+ uptake and K+ concentration. At tillering stage, GWAS was performed on rice exposed to short- , medium- and longterm salt stress based on ~ 200,000 SNPs. Around 1200 candidate genes associated with growth parameters, and Na+ and K+ content were identified.For salt treated rice at reproductive stage, only a study of Kumar et al. were reported. Based on 6000 SNPs, it was shown that 20 loci were associated with the Na+ /K+ ratio, and 44 loci were associated with other traits. Twelve association mappings with Na+ /K+ were located on chromosome 1 where Saltol, a major QTL that controls shoot Na+ /K+ homeostasis in rice at the seedling stage, is located. However, GWAS has not been applied for the analysis of photosynthetic and yield-related traits in rice exposed to salt stress at the flowering stage, which is a highly salt-sensitive stage. Additionally, no rice accession from Thailand where a large collection of diverse rice germplasms can provide new allelic diversity for salt tolerance, were analyzed by GWAS. The objectives of this research were to investigate and cluster Thai and Asian rice accessions based on physiological responses and yield-related traits under the salt-stress condition at the flowering stage and to perform GWAS for these traits to identify regions/genes responsible for salt tolerance.

The association panel consisted of a diverse collection of 190 rice cultivars including both standard salt-tolerant and salt-sensitive varieties. The rice accessions in this study were kindly provided by the Pathum Thani Rice Research Center . The experiment was designed with a randomized complete block design with four replications. According to the limitation of the time-consuming process of data collection, the experiment was performed in three separate sets of experiments. The standard salt tolerant and salt-sensitive cultivars were included in every experimental set. Twenty-one day old seedlings were cultivated using a hydroponic system with WP No. 2 nutrient solution and transplanted into pots containing soil and maintained until harvest. At heading stage in the flowering phase of each accession, water on the soil surface was drained before salt stress treatment. Rice plants were then watered with 900 mL of 150 mM NaCl solution to reach the desired final soil electrical conductivity of 8–9 dS m− 1 and treated for 9 days. For the control condition, rice plants were treated by tap water for the same period. To recover,vertical farming technology tap water was used to wash out salt ions in the soil every day until the soil EC was lower than 2 dS m− 1 ; this condition was maintained until harvest to collect yield-related traits. These experiments were conducted in the greenhouse facility at the Nakhon Ratchasima Rice Research Center, Rice Department, Ministry of Agriculture and Cooperatives. The air temperature was maximum at 32 °C with natural light and minimum at 21.1 °C during the night.

The average relative humidity was 72.5%. The short-sequence reads from the Illumina Genome Analyzer were grouped into the correct categories using the pipeline created by Missirian et al.. The rice reference genome was downloaded from the database , and indexed by SAMtools. Raw reads were aligned against the reference genome using the Burrow-Wheeler Aligner. Variants were called using genome analysis toolkit. Variants were filtered if they fitted the following criteria: to be called heterozygous, minimum coverage and minimum percentage of each of the two observed major base calls were 5 and 20, respectively and minimum total coverage was 10; for a position to be called homozygous, minimum coverage was 6 or 3 if positions with the minimum coverage of 6 were present in at least 10 accessions. SNP density was visualized using R ‘CMplot’ .We evaluated photosynthetic parameters and cell membrane stability on 104 rice accessions individually at the flowering stage after salt stress for 3, 6 and 9 days and analyzed yield-related traits at harvesting time. The mean values and frequency distributions of all parameters of each accession are shown in Additional file 2: Table S2 and Additional file 3: Figure S1. The highest reduction of phenotypic traits was observed at day 9 after salt stress: photosynthetic rate, PN ; stomatal conductance, gs ; transpiration rate, E , and cell membrane stability, CMS when compared with the control condition . However, we found that the mean values of intercellular CO2 concentration, Ci increased about 6% at day 9 after salt stress treatment. For yield-related traits, on average, number of tillers per plant, TIL; number of panicles per plant, PAN; number of filled grains per plant, FG decreased by 19, 11 and 26%, respectively, whereas number of unfilled grains per plant, UFG increased by 10% . To determine substantial genotypic variation in salt-stress responses, relative phenotypic values were calculated by the salt stability index of each rice accession [ × 100] . These parameters tended to decrease when plants were exposed to salt stress, except Ci , which tended to increase under salt stress. The variations of phenotypic traits were found in all parameters and were pronounced, particularly in the case of PN, FG and UFG . The relationships of the salt stability index of all parameters were determined by Pearson’s correlation r . We found a strong positive correlation between PN and gs, or E . PN also had a positive correlation with CMS, though weaker, at days 6 and 9 after salt treatment. Conversely, a strong negative correlation between PN and Ci was found. As expected for yield-related traits, the strongest positive correlation was observed between TIL, PAN and UFG. In addition, the relationship between photosynthetic performance and yield-related traits were observed. TIL was negatively correlated with gs at days 3 and 6; and with E at day 3. Similarly, PAN was negatively correlated with gs at day 3 as well as PN. Following the same trend, UFG was negatively correlated with gs or E at days 3 after salt treatment, and with Ci both at days 3 and 6. . In an opposite trend, a positive correlation was found between FG and gs at day 6. At day 9, no correlation was observed between photosynthetic parameters and yield-related traits.The list of rice accessions used for exome sequencing is shown in Additional file 1: Table S1. In total, 190 rice accessions were used for exome-sequencing, with the capture probes designed to cover about 50 Mb of the nucleotide target covering all 12 chromosomes of rice. SNPs that showed a minor allele frequency of < 5% of our population were removed to decrease overestimation of the effect of low-MAF SNPs. Therefore, the resultant number of 112,565 SNPs , which were high-quality SNPs genotyped across this population, was subsequently used for GWAS.EINGENSOFT was implemented for population structure analysis, which was based on PCA. Using SNPs identified by exome sequencing, two main sub-populations were delineated , consisting of five accessions in the first group and 185 accessions in the second group, respectively. The rice accessions in the first group included ‘Ai Tai’, ‘Jao Haw’, ‘Beu Saw Mi’, ‘E-Puang’ and ‘Leung Tah Young’ rice, which were grouped as upland rice .

Karl Hardy, in his excellent essay on the historical-colonial roots of “utopia” and the tentative possibilities of its use in Indigenous politics, cites research that Thomas More’s Utopia may have been the first instance of the Roman word colonia in the English language. Hardy also points out that More’s utopians are colonists themselves, who conquer lands near their island when necessary, and kill or “civilize” others when they are deemed to be using the land improperly . Early fictional utopias, the Christian utopias of the pre-Enlightenment especially, were steeped in colonial tropes: an explorer must sail a trans-oceanic ship to arrive at utopia, will sometimes encounter savages, and these explorers ostensibly seek riches of the new frontier.The colonial roots of utopia are well-outlined by Hardy, and scholars of science fiction show the ways this history still informs utopian fiction, for example in the ways the language of the frontier is used to describe cyberspace, and the ways aliens are racialized in narratives of space travel. The dystopian works I study are also primarily works of Indigenous Futurism. Grace Dillon defines the genre as work that “enclose ‘reservation realisms’ in a fiction that sometimes fuses Indigenous sciences with the latest scientific theories available in public discourse, and sometimes undercuts the western limitations of science altogether” .

These works estrange sf itself because they are often situated in an apocalypse that has already occurred — the colonial apocalypse — but they project a hopeful,vertical agriculture decolonized future from these ruins. Thus they are concerned with how historical colonialism continues into the present and permeates North American societies and cultures, as they interact with each other. Indigenous science and sustainability are common themes for Indigenous futurisms, hence they receive special attention in Chapter 2. Spiritual and physical healing at an individual and societal level — emphasizing balance and harmony with the environment — is also a predominant theme, and is especially reflected here in Chapter 4. All of the texts of this study are rich grounds for both Settler Colonial and Utopian Studies readings, but they work together on more than just a literary level. While they may make strange bedfellows, both Utopian and Postcolonial Studies have Marxist roots. Reading texts through a utopian and postcolonial lens makes up for what I see as two blind spots in utopian studies. First, contemporary utopian theory is centered around Western concepts of human rights and, while it gestures toward intersectionality, has to date not adequately grappled with just how contingent utopia must be in a global context. It is a commonplace that classical Marxism itself famously does not fully account for colonialism in its understanding of class struggle, a fact that postcolonial theorists since Fanon have sought to remedy. We can see this reflected in the context of utopian studies in Levitas’ Utopia as Method: her conclusion briefly cites global inequality as a major problem and advocates for international redistribution of wealth, but both the philosophy on which she draws and her concrete ideas for utopia as method are dependent on familiarity with the language and ideas of democratic socialism, a language that often does not account for Europe and the United States’ accumulated wealth through colonial dispossession, and as such is applicable to non-Western societies in a limited way, one that does not fully account for cultural difference. This understanding helps account for the ways that even sf from the political left, such as the works I study in Chapter 1, has not fully engaged with the inextricability of colonialism from class and race struggle.

Eurocentrism leads to another problem of utopian studies I also attempt to address: if we wish to decolonize the concept of utopia, we must engage with the violence of colonial oppression, and the likelihood that true decolonization in the form of the overthrow of capitalism globally will be likely violent. Power holds many tools of violence to protect its wealth , and anticolonial nonviolent resistance is routinely met with violence. Postcolonial studies, especially Settler Colonial Theory, also helps address this problem. SCT, which takes Frantz Fanon’s The Wretched of the Earth as a founding text, grapples with the bare fact that “decolonization is always a violent event” , and that nonviolence is typically called for by the colonizer when the colonized rebel against violence and dispossession, revealing the colonizer’s belief that only the colonizer has the only right to violence. While the fact of violence leaves everyone uneasy, and is a difficult subject even in Postcolonial Studies, it cannot be ignored simply because it is not part of the relatively peaceful utopian vision of the future. One way I suggest working through this uneasiness is to separate “violence” as harm to people and “vandalism” as harm to property. Though typically seen as synonymous, vandalism tends to be the form of resistance that the authors I study here are most concerned with, one that harms capitalist systems rather than individuals. Indeed, many of the texts I study will suggest that “utopia as method” — as a contingent, emergent practice that imagines and works toward radical change — will sometimes and in some places involve violent resistance, questioning the dichotomy between utopia as “peaceful” and dystopia as inherently violent . All of these texts have implications for activism that I will explore, within the context of my own subjectivity as a White scholar of European descent. In this spirit I echo Wolfe’s conclusion in Traces of History: “It is not my place to instruct colonized people on how to resist their condition, let alone to impersonate their agency … I have tried to offer an analysis, in the hope that it may prove useful” — useful to scholars who consider themselves activists and allies of colonized peoples, and who must grapple with these unsettling questions. In adding Postcolonial Science and Technology Studies and discussions of Indigenous Science to the mix in some chapters, especially Chapters 2 and 4 dealing with agricultural sciences and bio-piracy, respectively, I historicize the ways that colonization used/uses Western science and technology — to further utopian projects of colonization and globalization, and in doing so I take up the challenge postcolonial STS makes in decentering Western science and technology.

STS theorists observe the slippage between science fiction and science fact; some, like Colin Milburn, go so far as to suggest that science fiction is a sort of intellectual workbench of science . However, Western science fiction and the real-world projects which it reveals and reflects upon do not have a monopoly on techno-optimism. Instead, the texts I study puttechno-optimism to work in an anticolonial way, by subverting not-yet-existing Western technologies and by imagining indigenous technological innovations. The contention that postcolonial sf uses technology and/or utopian ideas more broadly as means of anticolonial subversion is not new. However, in my view, the subfield of Postcolonial SFS has an unfortunate tendency to situate colonialism in the past that can be corrected through a concerted engagement with Settler Colonialism. Patricia Kerslake, for example, in her work Science Fiction and Empire, not only considers colonialism a historical event but suggests that sf’s concerns with empire are not Western at all, but rather “the tendency we all share” to dominance and oppression. Ralph Pordzik, another problematic example,vertical farming aeroponics looks productively at third world sf in his book, The Quest for Postcolonial Utopia: A Comparative Introduction to the Utopian Novel in the New English Literatures. However, as Eric Smith notes, he subsumes his study in multiculturalism to the point of diminishing productive differences between different postcolonial geographies. Thus, an SCT-based study of dystopian speculative fiction and works of Indigenous Futurism can help correct this oversight and bring the discussion into our contemporary moment of increasing environmental instability and socio-economic upheaval. This study rethinks utopia against the anti-utopian projects of the settler colonizer, projects that began centuries ago and continue to this day. Some of these projects include: colonial attempts to increase the efficiency of land through new farming technologies, such as bioengineering; the use of genetics research on Indigenous peoples to further medical advancements that will not be accessible to research subjects; and using technologies of surveillance and security to maintain the borders of the settler colonial utopia. I discuss these and more in the following chapter outline, but first I must note that all of these technologies are forms of colonial violence in themselves, and are also protected with the use of violent and deadly technologies. Technologies of colonial violence loom large over the works I study, and also loom over every chapter.Without a doubt, fumigation has been one of the most controversial aspects of the process of eradicating illegal crops in Colombia. The toxicity of the herbicides used and the importance that fumigation acquired in the international strategy of the United States against drugs, have caused this subject to become an essentially polemical one.

The present article takes an historical look at the matter and describes and explains the fumigation policy imposed by the US on Colombia as part of a drug diplomacy which has characterized relations between the two countries over the past twenty-five years. Before beginning this chronology, however, it would be worthwhile to take a look at the basis for the US policy in this regard. Fumigation with herbicides corresponds to a rationale based on five premises: An implicit refusal to accept the notion that every demand produces a supply. When it come to repression, therefore, the emphasis is placed on growing, producing, processing, transporting and trading in drugs, rather than on the centers where drugs are consumed or on the places where there is the greatest margin of profit for the international illegal trade in drugs.It is assumed that, in terms of results and resources, strong repressive measures taken at the centers which provide drugs constitute the most effective way of combating the drug trade. It is assumed that punitive strategies designed and executed by those states in which the demand exists, and in those where the supply has originated, are pertinent when it comes to attacking a highly lucrative illegal trade that arises and evolves in a non-state situation and which is in the hands of powerful groups within society. It is assumed that, for the consumer countries, a greater and more effective eradication of illegal crops will lead to three results: fewer stimulants of this kind will be available on the market, they will be more highly priced, and they will be less pure. As a consequence of this triple assumption, it is supposed that there will be a decrease in urban criminality associated with drug dealing and a decrease in consumption. It is assumed that greater and more efficient eradication of illegal crops in the producing countries will lead, among other things, to a reduction in the value of illegal crops in the zones of production, a weakening of the drug traffickers’ power, a containing of violence generated by drug traffic affecting the more vulnerable sections of the population linked to these illegal plantations, and a decrease in the environmental damage caused by illegal plantations in soil which is fragile and extremely valuable. During the administration of President Julio César Turbay Ayala , Washington began putting pressure on the Colombian government to use chemicals for eradicating marijuana crops, especially in La Guajira on Colombia’s Caribbean coast. By 1978, Colombia had become the number one producer and exporter of marijuana to the United States. Of the 10,000 tons introduced into the US during that year, between 60 and 65 percent was supplied by Colombian traffickers. At the time it was estimated that Colombia had between 25,000 and 30,000 hectares planted with marijuana.During the administration of President Jimmy Carter , interdiction anderadication were the two keynotes governing international anti-drug policy. The attempt to manually eradicate marijuana plantations was no longer seen by Washington as sufficient. Congress and the White House began to agree that herbicides should be used to put an end to plantations not only of marijuana but also of poppies . In Latin America, herbicides had already been used in Mexico and in Jamaica. In the mid-seventies, Operación Condor in Mexico attempted to destroy marijuana plantations and was presented as a resounding success in the fight against drugs.

Harvesting activity moves to the coastal plains in the second quarter of April June, as lemons and oranges are harvested in southern California and vegetable crops are thinned and then harvested in the Salinas Valley of northern California. June marks the second highest month of employment on the state’s farms, as workers harvest strawberries and vegetables as well as early tree fruits, including cherries and apricots; melons and table grapes are harvested in the desert areas. Other workers thin peaches, plums, and nectarines, remove leaves in some vineyards, and thin large acreage crops such as cotton. Farm employment peaks in September, during the third quarter, reflecting the harvests of crops from Valencia oranges to tomatoes to tree fruits in the Central Valley of the state. However, the single largest labor-intensive harvest involves raisin grapes—some 40,000 to 50,000 workers have been hired to cut bunches of 20 to 25 pounds of green grapes and lay them on paper trays to dry into raisins. The workers typically receive $0.20 a tray, and the contractor who assembles them into crews of 30 to 40, and acts as their employer, receives another $0.05 a tray. During September, there is something of an early morning traffic jam, as vans ferry workers to fields and orchards,stackable flower pots and employers wanting to wait as long as possible to harvest to raise the sugar content of their grapes worry that not enough workers will show up.

During the fourth quarter, harvesting activities slow, and after the last grapes, as well as olives and kiwi fruit are harvested in October, most seasonal farm and food processing workers are laid off. Most workers remain in the areas in which they have worked—most workers are not migrants who follow the ripening crops—but many were born in Mexico, and some return to Mexico with their families for the months of December and January. If workers were willing to follow the ripening crops, and to switch between citrus and grapes, they could harvest work for 6 to 8 months a year.But few workers migrate from one area to another, and few switch crops within an area. In the mid-1960s, when migrancy was at its peak, a careful survey of farm workers found that only 30 percent migrated from one of California’s six major farming regions to another . A 1981 survey of Tulare county farm workers found only 20 percent had to establish a temporary residence away from their usual home because a farm job took them beyond commuting distance , and surveys of California farm workers in the 1990s found that fewer than 12 percent followed the crops . A 2000-01 survey of 300 farm workers found 19 percent who moved in the previous two years to find farm work; fewer than 25 percent planned to move in the current year to find a farm job . There are many reasons why most farm workers stay in one area of California: the harvesting of many fruits and vegetables has been stretched out for marketing and processing reasons; the availability of unemployment insurance makes migration less necessary; and some farm workers with children who are not likely to follow them into the fields realize that migrancy makes it very difficult for children to obtain the education needed to succeed in the U.S.

An easy test of the degree of follow-the-crop migrancy is to check turnover in a farm labor center.If follow-the-crop migrants filled the center, workers and families would be constantly arriving and departing, as they moved on to another job in a distant area. In fact, most migrant centers fill as soon as they open, and keep the same tenants for the season: workers know that they can obtain services for themselves and their children, especially in the state-run centers, and it is very hard to find alternative housing if the family packed up and sought another job in the manner of John Steinbeck’s Joad family.Until the 1940s, it was common for the wives of field workers to be employed in the packing houses that canned, froze or dried fruits and vegetables. However, after unions pushed packing-house wages to twice field worker levels in the 1950s and 1960s, packing-house jobs became preferred to field worker jobs, often representing a first rung up the American job ladder for field workers. About 40,000 workers are employed in the preserved fruits and vegetables subsection of the state’s manufacturing industry, down from 50,000 in the early 1990s.In the case of some vegetables and melons,  non-farm packing and processing jobs have been turned into farm worker jobs by field packing, having workers in the field put broccoli or cantaloupes directly intocartons rather than having the crop picked by field workers and packed by  non-farm workers in packing houses.4 In other cases, farm jobs have become  non-farm jobs, as when the cutting and packing of lettuce in the field is replaced by fewer workers simply cutting lettuce, and when there are more  non-farm jobs in packing plants as lettuce is cut and bagged: bagged lettuce uses almost 40 percent of U.S. lettuce.Employment on California farms was expected to drop sharply in the 1960s, as the end of the Bracero program, which brought Mexicans to work in U.S. fields between 1942 and 1964, was followed by sharply rising wages and unionization—the United Farm Workers union won a 40 percent wage increase in its first table grape contract in 1966. Processing tomatoes provides an example of the sharp drop in farm worker employment as a result of labor-saving mechanization.In 1960, a peak 45,000 workers, 80 percent Braceros, hand picked 2.2 million tons from 130,000 acres of the processing tomatoes used to make ketchup. In 2000, about 5,000 workers were employed to sort 11 million tons of tomatoes from 350,000 acres that were picked by machines.

The keys to tomato harvest mechanization included cooperation between scientists and between farmers, government, and processors. Plant scientists developed smaller tomatoes more uniform in size that ripened at the same time, and were firm enough so that the stalk could be cut, and the tomatoes shaken off, without damage. Engineers developed a machine to cut the plant, shake off the tomatoes, and use electronic eyes to distinguish red and green tomatoes and discard the green ones . Processors agreed to accept tomatoes in 12.5 ton truck mounted tubs rather than 60- pound lugs, and the government established grading stations at which random samples were taken to determine the quality and price. The cost of mechanizing the tomato harvest was relatively small—less than $1 million—and the estimated rate of return was hundreds of percent.5 The rapid diffusion of tomato harvesting machines in California—none were harvested by machine in 1960, and all were harvested by machine by 1970—was expected to usher in an era of machines replacing men on farms,flower pots for sale economists and engineers boldly predicted that, by 2000, there would be practically no jobs left for unskilled seasonal farm workers by 2000 .6 However, the cooperation between researchers, farmers, processors, and the government that transformed the processing tomato industry in the 1960s proved to be the exception, not the rule. Farmers remained very interested in and supportive of mechanization research during the 1970s, when there were hundreds of public and private efforts to develop uniformly ripening crops and machines to harvest them, but interest waned in the late 1970s due to rising illegal immigration and a lawsuit. Mexico devalued the peso in 1976, and in 1977, for the first time, apprehensions of unauthorized Mexicans in the U.S. first topped 1 million. Apprehensions remained at about 1 million a year until after 1982, when another peso devaluation caused them to jump by 25 percent, and the rising number of unauthorized Mexicans, many of whom were from rural Mexico and sought jobs on U.S. farms, guaranteeing an ample supply of hand workers. Meanwhile, the UFW and California Rural Legal Assistance in 1979 filed a lawsuit against the University of California , charging that efforts to develop labor-saving machines were an unlawful expenditure of public funds because they displaced small farmers and farm workers . The suit asked that UC mechanization research be halted and a fund was created to assist small farmers and farm workers equal in size to what UC earned from royalties and patents on agricultural innovations .The suit was eventually settled by establishing a committee to review research priorities, but public and private support for mechanization research decreased, and scientists and engineers moved on to other issues. Most labor-saving research today is conducted by the private sector, and most of it is far less visible than machines replacing 90 percent of the hand harvesters, as in tomato processing. Precision planting and improved herbicides have dramatically reduced the need for thinning and hoeing labor. Many farmers have planted dwarf trees to increase yields, which can also reduce harvest labor needs. Much of today’s mechanization is motivated as much for non-labor reasons as to save on labor costs. For example, drip irrigation systems reduce the need for water as well as irrigator labor, and a machine harvesting wine grapes at night results in higher-quality grapes and uses less labor.

In the 19th century, U.S. agriculture in general and California agriculture in particular were considered land-abundant and labor short, which led to labor shortages that were compounded in California by the dominance of large and specialized farms. California began producing fruits in the 1870s, when the completion of the transcontinental railroad and falling interest rates encouraged a shift from grazing cattle and growing grain without irrigation to labor-intensive, irrigated fruit and vegetable farming. The expectation was that large farms, many derived from Spanish and Mexican land grants, would be broken up into family-sized units and sold to farmers arriving on the railroad, because only with a family-farm system would there be enough workers for labor-intensive agriculture . However, large farms were not broken up into family-sized units because new workers were available to be seasonal farm workers. Some 12,000 Chinese workers had been imported to help build the railroad through the Sierra Nevada mountains and, when they were laid off in 1870, they were kept out of urban jobs by anti-Chinese movements . Chinese workers were paid low wages only when they were needed which helped to raise land prices, and made it hard for family farmers to buy land and get started in farming, and gave landowners an incentive to keep the door open to immigrants. However, anti-Chinese sentiment eventually led to a halt to Chinese immigration in 1883, but a new source of immigrant workers was found, in Japan. Japanese immigration was stopped in 1907, and workers were imported from present-day India and Pakistan until World War I. There was little immigration during World War I, when Mexico was experiencing a civil war. The U.S. government was trying to restrict immigration from Europe, imposing head taxes and literacy tests on new arrivals in 1917, but western farmers won an exemption for Mexican farm workers coming to the United States for up to one year, beginning the U.S.-government-approved recruitment of Mexican farm workers. There were many problems with this first Bracero program, and government approved recruitment was halted in 1921, but Mexicans continued to arrive and travel around California seeking farm work. Many Mexicans were sent back to Mexico during the Great Depression, and the source of farm workers in the mid-1930s shifted to the Midwest, where many of the Okies and Arkies who lost their farms during the so-called Dust Bowl moved to California, expecting to become small family farmers. The gaps between farmers and farm workers in California led to some of the most enduring American literature, including John Steinbeck’s 1939 novel, The Grapes of Wrath. Okies and Arkies continued to be the mainstays of the seasonal harvest work force in the 1940s, when “fruit tramps” migrated from farm to farm, but their children often went in to the military during World War II, or found jobs in wartime factories, and California farmers asked the federal government to once again approve the recruitment of Mexican Bracero workers. The federal government agreed, and the first of a series of Bracero agreements was signed in 1942; almost 5 million Mexican workers were admitted over the next 22 years—many individuals returned year after year, so that only 1 to 2 million Mexicans gained experience working on U.S. farms.

Agricultural producers in California received $586 million in federal assistance in 2001; Of this about $242 million came as production flexibility contracts and loan deficiency payments.The remainder of government payments to farmers came in the form of marketing support and conservation payments, which we discuss later in this chapter. While these federal government support payments are low in total compared to those states where the major agricultural products are grains or oil seeds, this does not imply that some agricultural producers in California do not benefit greatly from subsidies and protectionist measures.Over 100 farms in California received more than $425,000 each in subsidies in 2001 . Dairy, sugar and cattle producers receive significant protection from import barriers, and many producers receive subsidized inputs, particularly irrigation water. Sumner and Hart estimated the Producer Subsidy Equivalent paid to California agriculture in 1995 , where the PSE is defined as all government transfers to the industry including but not limited to production subsidies. They calculate that the California agricultural sector receives annual PSE transfers of $2.3 billion per year or about 11 percent of total commodity receipts. This is about one-half of the percentage PSE for all U.S. agriculture at the time,fodder sprouting system mainly because fruits and vegetables receive fewer transfers than the average commodity.

However, California’s PSE is higher than the percentage PSE received by producers in liberalized markets like Australia and New Zealand where the 1995 PSE was about 3 percent. While the specific estimates of PSE vary over time, the general pattern identified by Sumner and Hart, that California producers have a lower PSE than the U.S. national average but higher than that for other agricultural exporters, holds today.The formation of the Canada-United States Free Trade Agreement in 1989 and the North American Free Trade Agreement in 1994, has led to greatly expanded agricultural trade between Canada, California’s top market, and the U.S. NAFTA was designed to integrate economic activity among three nations: Canada, the U.S. and Mexico. It serves as a free trade agreement rather than a customs union or common market. Since 1989, U.S. agricultural exports to Canada have expanded by about 3 and one-half times, from $2.24 billion to $7.65 billion. Over the same period, agricultural imports from Canada have risen almost three-fold, from $2.93 billion to $8.66 billion. Fruits and vegetables account for more than one-third of Canada’s agricultural imports from the U.S., so California plays an important role in this north south trade. However, in spite of the CUSTA and NAFTA, Canada continues to intervene in agricultural trade flows. The country uses non-tariff barriers such as licenses that restrict imports of bulk produce, fresh fruits, vegetables, and wine. For instance, Canadian regulations on fresh fruit and vegetable imports prohibit consignment sales of fresh fruit and vegetables without a prearranged buyer . Canada also severely limits imports of dairy products, eggs, and poultry.

According to the WTO Appellate Body, Canada’s supply management system for dairy provides implicit export subsidies for these products . Producer groups in the U.S. have called for the greater use of non-tariff barriers to limit agricultural imports from Canada. This has often been accomplished by the use of U.S. trade remedy laws. Trade remedy laws are intended to offset “unfair” trade that injures domestic producers as a result of either foreign sales that are “dumped” into the U.S. at less than fair value or influenced by foreign government subsidies. The regular use of trade remedy laws within NAFTA illustrates the fact that any transition to freer trade in agriculture, even between countries at relatively similar stages of development, may be politically difficult. An example of the agricultural trade tensions between Canada and the U.S. is the recent “tomato wars,” in which U.S. producers accused the Canadians of “dumping” tomatoes in the U.S. market. In October 2001, the United States government made a preliminary ruling that Canadian growers were dumping greenhouse tomatoes into the United States at prices below the Canadian cost of production. As a result of this finding, Canadian sales into the United States were assessed an average tariff of 32 percent. Several weeks later, the legal tables were turned as the Canadian government initiated an anti-dumping investigation against the U.S. fresh tomato industry . The Canadian counterclaim may not have been a coincidence. Rather, it may have been a tit-for-tat reaction to the steep U.S. duties imposed on Canadian greenhouse tomato sales to the United States. By July 2002, both cases were resolved with identical rulings of no material injury.

While U.S. exports of fresh tomatoes to Canada declined 10 percent over the previous year during the period of investigation, Canadian imports of greenhouse tomatoes to the United States actually increased 17 percent over that year .Despite the fact that Japanese agriculture receives high levels of government support and has limited market orientation , it is also the world’s largest net importer of agricultural products. The United States supplies roughly one-third of Japan’s agricultural imports, and in 2002, Japan’s agricultural imports from the U.S. were valued at $8.3 billion . About 20 percent of these U.S. exports to Japan originated in California. Japan is California’s third largest export market for agricultural products, with rice, cotton, almonds, beef, and oranges ranking as the top commodities . Japan’s weak economy has dampened its total agricultural imports in recent years . In the 1990s, the most significant import growth in Japan was in the area of fruits and vegetables, wine, and beef . More recently, grains and oil seeds have done better . Japan continues to restrict imports of horticultural products, livestock products, and processed foods, all of which are important exports for California. Recently, beef exports to Japan were halted in response to the BSE scare in Europe; and Japan continues to consider implementing a “beef import safeguard,” which could further lower imports even further. At the time of this writing, Japan had halted all imports of U.S. beef, due to the discovery of BSE in the U.S. . Citing phytosanitary concerns, Japan blocks imports of U.S. fresh fruit, vegetables, and other horticultural crops, keeping Japanese domestic prices of horticultural products artificially high. Government subsidies are also provided to farmers to encourage them to divert land out of rice production and into vegetables . Japan also has country-of-origin labeling requirements for agricultural products that principally affect fruits, vegetables and animal products . This acts as a non-tariff barrier to trade. Japan maintains high tariffs on beef, citrus, and processed foods. In addition, imported high quality California rice is strictly controlled and rarely reaches the consumer food table in Japan. The over quota rice tariff in Japan exceeds 400 percent. Until recently, Japan’s system of food imports used mainly non-tariff barriers such as quotas and licenses, instead of tariffs. Sazanami et al. found that Japan’s tariffs on food imports averaged only 8 percent, but the quantitative import barriers averaged 272 percent, with the rice tariff equivalent barrier at 737 percent. Despite the tariffication required by the Uruguay round of trade liberalization, of Japan’s agricultural imports remain highly protected . In addition, Japan continues to use health and safety regulations to serve as barriers to trade.3 In the case of fresh oranges and lemons, the U.S. is the largest supplier to Japan,microgreen fodder system accounting for over 80 percent of Japan’s imports. Other exporters of oranges and lemons of lesser importance in Japan are Australia, Chile, and South Africa. The Japanese Government continues to impose a high import tariff on fresh oranges. The tariff rate is 32 percent for imports during the December-May period, and 16 percent during June-November. .California’s second most important market, the EU, provides export subsidies for beef, cheese, other dairy products, and processed fruit, in competition with California. It also provides generous production subsidies on horticultural products such as tomatoes, grapes, peaches and lemons. The EU’s subsidized production of these products affects California’s competitiveness in third markets.

More generally, the EU’s Common Agricultural Policy significantly isolates European farmers from international competition. The CAP is a system of subsidies and market barriers that include mandatory land set-asides, commodity specific direct payments, and export subsidies . Support to agricultural producers as a share of total agriculture receipts is 40 percent higher in the EU than in the U.S. . Much of this support comes in the form of higher prices paid by domestic consumers. Recently, there has been increasing pressure to significantly reform the CAP; the program has been called by the popular press an “extravagant folly” and “demented” . These publications and others have argued that reform of the CAP will be a critical element of the next round of trade negotiations, if these talks are to be successful. Enlargement of the EU to include ten Central and Eastern European countries will also create pressure for further reform. Structural reforms of European agricultural policy will have important implications for California, both because the region competes in third markets with California, and because the region is an important customer, as discussed earlier. If the existing EU agricultural policy is applied to the 10 new member countries, the incentive will be to increase production and agricultural exports. Several of the new member countries have a comparative advantage in agriculture, especially in the area of wheat, coarse grains, and livestock. California agriculture will benefit if this expanded production results in budgetary pressure to reform the CAP. In addition, California agriculture may well benefit from projected income growth in Central and Eastern Europe that results from EU membership. Higher incomes in this region will lead to increased demand there for high-valued food, of the type exported from California. An ongoing trade dispute between the US and the EU concerns the use of geographical indicators . The EU wants to prohibit foreign producers of food and beverage products from labeling products with European regional names . The list of products that will receive this protection is an on-going subject of negotiation at the WTO. For California there is a trade-off associated with GI protection. On the one hand, California would have to stop using certain names if the EU is successful . On the other hand, California agriculture could use GI protection to develop niche markets for its food and beverage products, potentially capturing a price premium.China is a relatively new member of the WTO, and developments in China’s agricultural trade are being carefully watched by the California industry. China’s land area sown to fruits, nuts, and vegetables has grown rapidly in the past decade, and trade is expected to take on a greater importance for China in coming years now that it has joined the WTO. China’s horticultural exports account for more than one-half of its agricultural exports . Given China’s rich agricultural resources, abundant labor supply, and large population, it has great potential to play a much more prominent role in agricultural trade in the coming years, as both an exporter and an importer. China uses both tariff and non-tariff barriers to restrict agricultural imports. China has in place high import tariffs on certain agricultural commodities currently exported by California, such as citrus, table grapes, wine, beef and dairy products. There is also evidence that the value added tax in China, as currently applied, results in a price break for domestic field crops as compared to imports, of about 4 percent . China has import tariffs on citrus and table grapes of approximately 10 percent and maintains a restrictive tariff rate quota on cotton. As part of its WTO accession negotiations, China agreed to a significant lowering of these tariffs to around 10 to 12 percent. In addition, if the WTO liberalizes world trade in clothing and textiles , then China will undoubtedly expand exports of clothing and textiles. This could result in increased imports of cotton into China. Domestic developments in China not directly related to trade policy but related to rising incomes may also present opportunities for California agricultural exports to that country. For example, both the USDA Foreign Agricultural Service and the popular press have recently highlighted the growing importance of western-style supermarkets in Chinese cities, replacing more traditional markets. This may present a new opportunity for California producers, with new opportunities to supply pre-packaged or processed products and products that require refrigeration.

Fruits,tree-nuts, and vegetables represent about half of these totals, while dairy and poultry products, and grains are also major contributors.In 1998, fresh and processed fruits, tree-nuts, and vegetables had the greatest impact of any commodity group on California’s economy, generating about half the direct and indirect sales, total income, value added and jobs related to agriculture. About one third of the $33 billion in direct sales in this category was attributable to sales of alcoholic and non-alcoholic beverages. Examples of beverages linked to fruit, tree-nut and vegetable production include wine and juice. Some of the beverages included in this category may reflect processing of grain products rather than fruit, tree-nuts and vegetables. Dairy and poultry products and grains also had significant economic contributions, accounting for between 10 percent and 20 percent of the total income, value added, and jobs related to agriculture.Because of its climatic advantages, California is able to produce a great variety of products that are not grown extensively elsewhere in the United States. The California Department of Food and Agriculture estimates that the state is the leading U.S. producer for about 65 crop and livestock commodities.

Fifty-five percent of the value of California agriculture’s $26.1 billion in 2002 farm gate sales is contributed by the fruit , vegetable , and nut industries. Indeed, California dominates the U.S. horticultural sector, accounting for approximately 37, 55 and 85 percent, respectively, of the 2002 farm gate value of the principal vegetables, fruit, and tree nuts produced in the United States . California’s leading position in the $30.8 billion U.S. horticultural industry is explained by climatic, technological, and infrastructure advantages, as well as the market- and consumer-driven orientation of its agribusiness managers. Given the importance of horticultural crops to California agriculture,dutch bucket hydroponic and to the nation, our discussion draws heavily on examples from this sector.Many of California’s fruits and vegetables are highly perishable, and production is seasonal. A major challenge in marketing is to ensure both the high quality of these products and their availability to consumers year-round. Another key challenge facing marketers is the maturity of the U.S. market. Both the U.S. population growth rate and the income elasticity of demand for food are low, meaning that the market for domestic food consumption expands only slowly over time, and firms are essentially competing for share of stomach. This competition has intensified given the high rate of new product introductions and expanded year-round availability of formerly seasonal items, often through imports. Both of these factors have led to a greater array of substitute products, frequently dampening demand for large-volume staples like oranges and apples.

California’s bounty also presents opportunities. Through the diversity of its agricultural production, firms marketing California produce have the opportunity to provide food retailers with complete lines of fruits, vegetables, and nuts. Because California produces a large share of the U.S. supply of key commodities such as almonds, lemons, olives, lettuce, prunes, strawberries, table grapes, processing tomatoes, and walnuts, California producers and marketers traditionally had unique opportunities to exercise control over the markets for those commodities. However, expanding world supply of many commodities has reduced California’s share, increasing competition and presenting new marketing challenges. This chapter documents the importance of marketing in both U.S. and California agriculture and highlights the institutions that have emerged and the strategies that have been pursued by California’s food marketing sector to compete effectively in this market environment.The U.S. food industry is the largest in the world. The final value of food sold through all retail channels was $485.2 billion in 2002 with an additional $415 billion sold through foodservice channels . Marketing functions account for the largest share of the U.S. food dollar, and the percentage of food costs due to marketing is rising over time. Food marketing thus has an important effect on the welfare of both consumers and farmers. The U.S. Department of Agriculture maintains two general measures of relative food costs. The market basket consists of the average quantities of food that mainly originate on U.S. farms and are purchased for consumption at home.

The farm share of the value of the market basket remained stable at about 40 percent from 1960- 80 but has declined rapidly since then, to 30 percent in 1990 and 21 percent in 2001. Table 1 depicts the trend in farm share for selected commodities of importance to California. Although farm value has traditionally accounted for more than 50 percent of retail value for animal products such as meat, dairy, poultry, and eggs, those shares have now fallen well below half. The farm share for fruits and vegetables tends to be much lower and does not differ much between fresh and processed fruits and vegetables.The second major measure of food marketing costs in the U.S. is the marketing bill, which is calculated as the difference between what consumers spend for domestically produced farm foods and what farmers receive. In 2001 the farm share of the food marketing bill was 19 percent. This measure of the farm share has also been declining steadily over time, falling from 41 percent in 1950 to 31 percent in 1980 and then to 24 percent in 1990. The marketing bill takes account of food expenditures both at home and in restaurants. The proportion of the U.S. food dollar spent outside the home has been rising rapidly. In 2002, such expenditures accounted for 46 percent of the food budget compared to 37 percent in 1990 and 32 percent in 1980.While the overall U.S. food market is characterized by slow growth, eating habits are becoming more diverse. Demographic and psychographic trends, such as ethnic diversity and new attitudes about food consumption as it relates to self-identity and well-being, have contributed to a much more segmented market. Food marketers must increasingly target specific consumer segments rather than employing mass marketing strategies. More retailers are looking to their suppliers to assist them in understanding and better serving different types of consumer segments. In response, many suppliers are becoming involved in new types of marketing services, including consumer research and category management. The latter is designed to help retailers improve net profitability for a category of products through efficient assortment, pricing, promotion and shelf-space management. For suppliers the aim is to focus on identifying and servicing the evolving needs of specific accounts as a preferred supplier, rather than marketing more homogeneous products with fewer support services on a spot market basis. The U.S. retail industry is dominated by chain stores. In 2002,dutch buckets system retail chains accounted for 83 percent of supermarket industry sales vs. 58 percent in 1954 . The remainder of sales is by independent stores, although the vast majority of these stores are affiliated to buying groups, either voluntary chains such as Supervalu or to a lesser extent retailer cooperatives such as Associated Wholesale Grocers. In 2002 there were 32,981 supermarkets including all format types. Firms in the U.S. food-marketing sector often view a large market share, including, if possible, the position of market leader, as a key requisite to success. Pursuit of market share has led to a dramatic consolidation in the U.S. food chain at all levels, ranging from the farm through food retailing.

Due to the difficulty of capturing sizable market share from rival firms, many U.S. food marketers have pursued share growth through mergers and acquisition of rivals. Mergers and acquisitions in the food sector occurred at a rapid pace in the 1980s, temporarily peaked in 1988 at 573 mergers, declined and then reached an all-time high of 813 in 1998, since declining to 415 in 2003 . Although the growth in merger activity has temporarily abated, cumulative activity in recent decades has likely had important implications for the structure of competition in the U.S. food sector. Consolidation occurring at the food manufacturing level has progressed rapidly for some time. About 16,000 food and tobacco processing companies operate in the U.S., but in 1997 about 75 percent of sales were by the 100 largest of these firms. The largest sales growth, fueled mostly by mergers and acquisitions, has been recorded by the top 20 of these 100 firms, which in 1997 were estimated to account for about 50 percent of value added in food manufacturing . Most of the 53 food and tobacco industries surveyed in the U.S. Census of Manufacturing have experienced increasing concentration over time. The average market share held by the four largest firms in these industries has risen from 43.9 percent in 1967 to 53.3 percent in 1992, the most recent year for which data are available. In contrast to the food manufacturing sector, over the decade 1987-97 retail concentration ratios were quite stable with the share of U.S. food sales accounted for by the top 4, 8 and 20 retailers at about 20, 30, and 40 percent, respectively. During this decade new players were emerging in the U.S. food system, including value oriented retailers such as Wal-Mart with its fast expanding super center and club store formats, specialty food retailers like Trader Joe’s, European entrants into U.S. food retailing, and other mass and drug store merchandisers entering the food business. This phenomenon is called channel blurring and continues with the recent emergence of “Dollar Stores,” on-line food shopping and the on-going competition from the food service sector for the consumer food dollar. This challenging marketplace motivated many conventional retailers to become larger in hopes of improving their competitiveness. From 1997-1999, in particular, mergers occurred between several already large retail chains, beginning to induce important and still unfolding changes in relationships between buyers and suppliers. By 2002 the estimated share of U.S. food sales accounted for by the top 4, 8 and 20 retailers had reached 31, 45, and 57 percent, respectively. This means that in 2002 suppliers faced a market where only 20 retail firms sold at least $276 billion in food. Despite the mergers, the United States has no truly national supermarket chains. In 2002 only eight chains had over 1,000 stores, and only one of these has over 2,000 outlets. Given the large geographic size of the United States, chains tend to be regional in focus. However, the recent high merger activity has contributed to much larger chains than ever before, with five surpassing $25 billion in sales in 2002, and four with stores in over half of the country. Still, many local and regional chains remain quite competitive by staying in close contact with their customers and implementing highly targeted marketing strategies. The regional, ethnic and demographic diversity of U.S. consumers leads some to predict that small to mid-size chains may have an important role to play for some time to come. Within the retail channel the super center concept has emerged as a major industry force, which further concentrates buying power in the hands of a few very large new players. Super centers are a type of mass merchandising format combining a full-line supermarket with a full-line discount department store and range up to 24,400 square meters in size , compared to 4,900 square meters for the average supermarket. Total 2002 grocery-equivalent sales of super centers were estimated at $45.5 to $50.3 billion with total super center sales reaching $116.7 billion . The largest entrant to this format is Wal-Mart, with an estimated $29.3 billion in U.S. grocery-equivalent 2002 food sales, a 75 percent share of national super center sales and 1,333 super centers as of mid-2003. Already the largest retailer in the world, operating in ten countries, Wal-Mart is opening over 200 new super centers per year in the U.S. alone, and is fast becoming the dominant global player in grocery retailing with $244.5 billion in 2002 global sales among all its store formats, including large discount stores and warehouse club stores . Wal-Mart has also entered the conventional grocery-retailing sector in the U.S. with 52 neighborhood markets in 2002, and growing. Wal-Mart’s immense buying power combined with its approach of driving non value-adding costs out of the food system appears to have raised the competitive benchmark for conventional retailers. It emphasizes supply chain management via covendor managed automatic inventory replenishment procurement systems.

For these reasons California became the only substantial market for the header technology. The header technology evolved in an entirely different direction from the reaper, leading directly to the development in California of a commercial combined harvester. From the starting point of the header, it was quite simple and natural to add a thresher pulled along its side. There had been numerous attempts in the East and Midwest to perfect a machine that reaped and threshed in one operation. Among those that came closest to succeeding was Hiram Moore’s combine built in Kalamazoo, Michigan, in 1835. But in the humid Midwest, combining suffered from the same problems with moisture that had plagued heading. In 1853 Moore’s invention was given new life when a model was sent to California, where it served as a prototype for combine development.35 After several decades of experimentation in California, workable designs were available by the mid-1880s and the period of large-scale production and adoption began. Most of the innovating firms, including the two leading enterprises—the Stockton Combined Harvester and Agricultural Works and the Holt Company—were located in Stockton. During the harvest of 1880 “comparatively few” machines operated in California,planting gutter and agricultural authorities, such as Brewer and Hilgard, clearly suggest that even those machines should be considered as experimental. In 1881 about 20 combines were under construction in Stockton.By 1888, between 500 and 600 were in use.

The first truly popular model was the Houser, built by the Stockton Combined Harvester and Agricultural Works. In 1889, its advertisements claimed that there were 500 Houser machines in use, and that they outnumbered all of the competitors put together. Soon thereafter, machines in the Holt line overtook the Houser. The innovative products of the Holt company, which included in 1893 the first successful hillside combine, became dominant on the West Coast. By 1915 Holt’s advertisements boasted that over 90 percent of California’s wheat crop was harvested by the 3,000 Holt combines in the state.It is important to recognize that the adoption of combine-harvesters east of the Rockies was only in its infancy at this date. Combine models that eventually were adopted in the Midwest and Great Plains were considerably smaller than West Coast machines. The primary reasons for the differences were undoubtedly cost and scale considerations, but the prejudice in the East that large teams of horses were unworkable and the lack of practice probably played important roles.In California the opposite attitudes were said to prevail. The Pacific Rural Press boasted “f one man could drive all the mules in the State it would be the acme from one point of view.”California farmers had gradually developed their ability to manage large teams as a result of their experience with gang plows and headers.The difficulties associated with controlling large teams induced Holt and others to perfect huge steam tractors to pull their even larger harvesters. While steam-driven combines never came into vogue, these innovative efforts did have one highly important by-product—the track-laying tractor. The first practical track-laying farm tractors were initially developed to operate on the soft soil of the Sacramento-San Joaquin Delta.Although the crawlers were first designed to solve a local problem, this innovation was of global significance.

The Caterpillar Tractor Company would build larger, more powerful equipment that rapidly spread throughout the world. The reoccurring pattern of one invention creating new needs and opportunities that led to yet another invention offers important lessons for understanding the lack of development in other times and places. The key to explaining the progression of innovations in California was the close link between manufacturers and farmers that facilitated constant feedback between the two groups and the keen competition among producers that spurred inventive activity. Entrepreneurs seeking their fortunes were in close tune with their potential customers’ needs and vied with one another to perfect equipment that would satisfy those needs. Where these forces were not at work, the burdens of history severed the potential backward linkages that are so critical for economic development.Just as there were major investments in mechanical technologies to increase the productivity of labor, there were also substantial investments to increase the productivity of California’s land. These included agro-chemical research, biological learning concerning appropriate crops and cultural practices, and land clearing and preparation, but the most notable were investments in water control and provision. These took two related forms.In this realm, Californians literally re-shaped their landscape as individual farms leveled the fields and constructed thousands of miles of ditches. In addition, individual farms, reclamation districts, and the Army Corps of Engineers built several thousand miles of major levees to tame the state’s inland waterways. The second form consisted of a variety of measures to supply the state’s farms with irrigation water. Table 1 details the growth in the state’s irrigated acreage between 1890 and 1997. Expansion occurred in two main waves: the first lasting from 1900 through the 1920s and the second, linked to the Central Valley Project, during the decade after World War II.

Much of the historical growth of irrigation was the result of small-scale private initiatives rather than large-scale public projects that have attracted so much scholarly attention. Up until the 1960s, individuals and partnerships were the leading forms of organization supplying irrigation water. These forms accounted for roughly one-third of irrigated acres between 1910 and 1930, and over one-half by 1950. These small-scale irrigation efforts were closely associated with the rising use of groundwater in California over the first half of the twentieth century. Between 1902 and 1950, the acreage irrigated by groundwater sources increased more than thirty fold, whereas that watered by surface sources only tripled. Groundwater, which had supplied less than 10 percent of irrigated acreage in 1902, accounted for over 50 percent of the acreage by 1950. This great expansion was reflected in the growing stock of pumping equipment in the state. Underlying this growth were significant technological changes in pumping technology and declining power costs. During the 1910s and 1920s, the number of pumps, pumping plants, and pumped wells doubled each decade, rising from roughly 10,000 units in 1910 to just below 50,000 units in 1930. Pumping capacity increased two-and-one-half to three times per decade over this period. Expansion stalled during the Great Depression, but resumed in the 1940s with the number of pumps, plants, and wells rising to roughly 75,000 units by 1950. Individuals and partnerships dominated pumping, accounting for about 95 percent of total units and approximately 80 percent of capacity over the 1920-50 period.Since the 1950s, there has been a shift away from individuals and partnerships, as well as groundwater sources. By the 1970s, irrigation districts—public corporations run by local landowners and empowered to tax and issue bonds to purchase or construct, maintain,gutter berries and operate irrigation works—had become the leading suppliers. The district organization rapidly rose in importance over two periods. In the first, lasting from 1910 to 1930, acreage supplied by irrigation districts increased from one in-fifteen to approximately one-in-three. Much of this growth came at the expense of cooperative and commercial irrigation enterprises. Between 1930 and 1960, the district share changed little. During the 1960s, the district form experienced a second surge in growth, which was due in part to the rising importance of large-scale federal and state projects, which distributed water through these organizations. By 1969, irrigation districts supplied more than 55 percent of all irrigated acreage.Few issues have invoked more controversy in California than recurrent problems associated with agricultural labor. Steinbeck’s portrayal of the clash of cultures in The Grapes of Wrath represents the tip of a very large iceberg. The Chinese Exclusion Act, the Gentlemen’s Agreement aimed at Japanese immigrants, the repatriation of Mexicans during the Great Depression, the Great Cotton Strikes of 1933, 1938, and 1939, the Bracero Program of the 1940s, ‘50s, and ‘60s, the UFW and Teamsters organizing campaigns and national boycotts, the state’s Agricultural Relations Act, the legal controversy over the mechanization of the tomato harvest, and the current battles over illegal immigration are all part of a reoccurring pattern of turmoil deeply rooted in California’s agricultural labor market. There are few if any parallels in other northern states; clearly, the history of agricultural labor in California is very different. For all the controversy, however, the state’s farms have remained a beacon attracting large voluntary movements of workers seeking opportunity. Chinese, Japanese, Sikhs, Filipinos, Southern Europeans, Mexicans, Okies, and then Mexicans again have all taken a turn in California’s fields. Each group has its own story, but in the space allotted here we attempt to provide an aggregate perspective on some of the distinguishing characteristics of California’s volatile agricultural labor market. The essential characteristics of today’s labor market date back to the beginning of the American period. Table 2 offers a view of the role of hired labor in California compared to the nation as a whole.

Expenditures on hired labor relative to farm production and sales have generally been two-to-three times higher in California than for the United States. Within California the trend shows some decline. Another important perspective is to assess the importance of agricultural employment in the economy’s total labor force. Here the evidence is somewhat surprising.Both agriculture and agricultural labor play a relatively prominent role in most renderings of the state’s history. But as Table 2 indicates, until the last two decades, agricultural employment in California has generally been less important to the state than for the country. Clearly, it is the special nature of the state’s labor institutions, not their overall importance in the economy, that warrants our attention. From the beginning of the American period, California farms have relied more extensively on hired labor than their counterparts in the East. At the same time Californians never developed the institutions of slavery or widespread share-cropping as did their counterparts in the South. The parade of migrants who have toiled in California’s fields has often been described as “cheap labor.” But this appellation is something of a misnomer, because the daily wage rate in California was typically substantially higher than in other regions of the United States, one of the world’s highest wage countries.In an important sense the “cheap labor” in California agriculture was among the dearest wage labor on the globe.In addition, one of the remarkable features of California agriculture is that the so-called “development” or “sectoral-productivity” gap—the ratio of income per worker in agriculture to income per worker outside agriculture—has traditionally been relatively narrow.This finding in part reflects the relatively high productivity of the state’s agricultural sector. It also reflects demographic factors. Due to low rates of natural increase, California’s farm sector never generated a large home-born surplus population putting downward pressure on rural living standards. Instead, the sector attracted migrants from the surplus populations of other impoverished regions of the world. For these migrant groups, agricultural labor was an entry point into a generally robust and dynamic economy.To a significant extent, past cohorts or their descendants, through hard work and high savings rates, have managed to advance up the occupational ladder.Over the long run of California’s history, agricultural labor has not been a dead end pursuit creating a permanent class of peasant laborers. This is an important point, because the agricultural history literature laments the end of the “agricultural ladder,” whereby workers start off as laborers or sharecroppers and work their way up to cash tenants and then owners of their own farms. According to the traditional literature, ending this process represents one of the great failings of nineteenth century American society.The literature is particularly critical of California because of its large farms and high ratio of hired workers to farm owners. But a little serious thought suggests how misguided these concerns are. Engel’s Law tells us that as income per capita grows, a smaller percentage of income will be spent on food. This suggests that in a growing economy the agricultural sector would diminish in size relative to the non-agricultural sector. At the same time the closing of the frontier meant that the total supply of agricultural land could not continue to grow as it did for most of the nineteenth century. Thus, unless farms were Balkanized into smaller and smaller units there was no possible way for the nineteenth century ideal to have continued.