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Genetic diversity in Lathyrus sativus L. germplasm

Reda H.Sammour

Grass pea (Lathyrus sativus L.) is food, feed and fodder crop. The total acreage of grass pea is estimated at 1.50 million ha with annual production of 1.20 million ton. Lathyrus sativus has extensive tolerance of drought, waterlogging and poor semiarid soils; resistance to insects and pests. The crop originated in the Balkan Peninsula. It favours self-pollination. However, there have been indications that some out crossing occurs in the species (from 9.8 to 27.8%). The seeds of L. sativus provide a source of protein and carbohydrate that are able to sustain life during periods of famine when other food is unavailable. However, the presence of neuro-toxic ODAP in the different parts of the plant is limiting the use of this crop.Astudy of genetic diversity and its relation to geographical diversitymay contribute information about the center of diversity and origin of domestication of a cultivated crop. The genetic variation can be exploited in breeding programmes aimed at crop improvement. Vast arrays of analyses are used worldwide to estimate genetic variability. L. sativus shows great morphological variation, especially in vegetative characters such as leaf length, while floral characters are much less variable. L. sativus ecotypes are classified on the basis of flower color, marking on pods, and size and color of seeds, which in many cases is connected with their geographical distribution. These characteristics, as well as yield and also nutritional traits of seeds have been estimated to describe the great variability of accessions of both, L. sativus and L. cicera. Cytological investigations have shown that the basic chromosome number of x = 7 is constant throughout the genus and that most of the species are diploid, with polyploidy as rare exceptions. Despite this stability in chromosome number, large variations in chromosome size have played an important role in the evolution of Lathyrus species. SDS-PAGE analysis of reduced seed globulins of lathyrus species showed intra-specific variation due to individual variation and/or differences among accessions. It has been repotted that SDS-PAGE of albumins and globulins of different grass pea even of the same geographic origin, have variation in number, width and intensity of bands, concluding that geographical origin does not influence specific seed protein contents and its polymorphism. In grass pea, the literature on both genetic diversity and intra and inter-specific-relationships among collections based on the electrophoretic analysis of isoenzyme is quite poor. Molecular markers including AFLPs, RFLP, RAPD, ISSR and EST-SSRs have proved to be useful for assessing genetic relationships, taxonomic and phylogenetic relationships within and between the sections and the species of the genus Lathyrus.