Genetic diversity and population structure analysis of Grass pea (Lathyrus sativus L.) accessions collected from North-Western Ethiopia using SSR markers

Grass pea (Lathyrus sativus L.) is a legume crop known to be an excellent source of protein, tolerant to drought, waterlogging, and salinity. The crop is used as an alternative source of protein to reduce malnutrition for resource-poor people and farmers leaving in marginal areas. However, due to the presence of a neurotoxin that causes lathyrism in the crop, it has been neglected and underutilized. As a necessary first step towards, therefore, this investigation was undertaken to assess the genetic diversity and population structure that existed within grass pea accessions collected from North-West Ethiopia using simple sequence repeat markers. Twenty-five grass pea accessions collected from the Ethiopian Biodiversity Institute were planted at the College of Agricultural Science, Ebonyi State University, Nigeria. The genomic DNA was extracted using Quick-DNA (TM) ZR Plant/Seed Miniprep Kit and amplified in an ABI Veriti PCR machine with 10 pairs of SSR markers in IITA, Ibadan, Nigeria. Out of 10 SSR primers, only eight primers were polymorphic. A total of 41 alleles were detected with an average of 5.13. The Polymorphism Information Content and Gene Diversity values ranged from 0.074 to 0.944 with a mean of 0.474 and 0.536 respectively. The largest pairwise genetic distance (0.365) was detected between North Gondar and East Gojjam populations. The CYRILLIC CAPITAL LETTER EFPT (analog of FST test) estimated through AMOVA were 0.24, 0.20, and 0.05 for within accessions, among regions, and population within regions respectively. The highest genetic differentiation value (76%) resides within accessions followed by 20% among regions. Both the population structure and cluster analyses grouped the 25 grass pea accessions into two distinct subgroups. This grouping pattern indicates the presence of gene flow among geographic regions. In general, the findings of this study indicate that despite few numbers of SSR markers it was possible to detect genetic diversity among grass pea accessions indicating the power of the SSR marker in picking up the existing genetic diversity within the studied accessions.