According to Pichon et al., P. xylostella can be regarded as a species highly polymorphic. This has been confirmed by Marthur et al. who indicated a strong genetic diversity in populations of box tree moths from different regions of southern and northern India.Differences in the degree of resistance to insecticides between populations can result from selection of different pressures attributable to the local variation in the way of using insecticides. It is in such a context, that this study has been carried out, to determine the diversity and the genetic structuration of P. xylostella populations in Senegal. To detect expansion signs of the breakdown area of P. xylostella populations, as well as Tajima D and the fs of Fu tests have been carried out. Moreover, the test Fs of Fu is very sensitive to demographic expansion, which generally founds expression in negative values.
These tests have been worked out using Arlequin v. 3.1. Mismatch distribution graphs are constructed with the help of the DnaSPv. 5.10 . But the indexes that go with it, particularly SSD and Rag, have been estimated owing to Arlequin v. 3.1 . For high resolution concern, erection of the phylogenetic trees has been done using two different methods: Neighbor-Joining method where calculation takes into account genetic distances by using the Kimura two parameters method, and the method of maximum probability which even shows us the history of our set of data. Research process of a phylogenetic tree, by using maximum probability,implies finding the typology and the length of the tree’s branches that will give us the highest probability to observe the DNA sequences in our data. The most appropriate model to build this tree is that of GTR added to the law of Gama.These two trees have been built, using Mega software v. 5.05 .
Efforts during last few decades had provided Africa with some success in increasing net agricultural productivity , but rapid population growth and environmental degradation acted to diminish the outcome of this success in many countries like Ethiopia . With continued increase in population pressure and land holdings continuously shrinking, many poor smallholders have resorted to more frequent cropping, curtailing traditional long fallows and increased use of inorganic fertilizers. Ethiopia is one leading Sub-Saharan country to liberalize its economy and develop poverty reduction strategies through market-led, broad based agricultural development during early 2000s, so in the 2012/13 fiscal year Ethiopia’s economy grew by 9.7%, the tenth year in a row of robust growth. Agriculture, which accounted for 42.7% of GDP, grew by 7.1%, while industry, accounting for 12.3% of GDP, rose by 18.5% and services, with 45% of GDP, increased by 9.9% in 2012/2013. Although Africa’s average growth declined from 5% in 2010 to 3.4% in 2011, the Ethiopian economy continued on the high-growth trajectory, and this momentum was expected to continue in 2012 and 2013 .
However, the growth in economy has been unevenly distributed, in most rural areas lasting effects of poverty, hunger, malnutrition still weigh heavily on the Ethiopian economy . As 93% of Ethiopians are currently engaged in small scale agriculture and other manual intensive activities, economic loss due to malnutrition estimated to cause reduced productive capacity at ETB 12.8 billion in 2009 which is equivalent to 3.8% of GDP. Ethiopia being the second most populous country in Africa , the rural population accounting for 82.4% , majority depending on traditional rain fed agriculture in the small farm dominated agriculture sector, the stability and sustainability of development have been heavily dependent on climate.Traditional agriculture, dominated by non-mechanized farming in highly uneven landscape, small-scale farmers is responsible for 95% of the cultivated land, mainly for subsistence needs employing 80% of the population.Entire food supply comes from rain fed subsistent agriculture and rainfall failure means loss of major livelihood source, which affirms that improving agricultural production is of paramount importance for the country’s economic progress ; especially in the background of wide poverty, food security has a primary focus not only in Ethiopia but all over Africa. In fact, different types of traditional small farm systems are providing food for more than 70% of the global population .
Most of Ethiopian subsistence farmers have small land holdings,the average of 1.2 hectares of land, with 55.13% less than one hectare . Thus, through strengthening these traditional small food production systems with a balance of modern knowledge/technology and environmental management using traditional knowledge with economic support, the countries like Ethiopia can try to attain sustainable food production .Traditional agriculture here in Ethiopia, follows age old practices that evolve before introduction of highyielding varieties and synthetic agro-chemicals. Many small scale farmers are still adapting the local varieties,using local land-climate-vegetation characteristics for sustaining productivity and conserving the natural resource base. In modern terms this “resource-conserving agriculture” has proved to have sound potential for improving livelihoods of smallholders in Africa.