Genetic diversity and population structure analysis of Pisum sativum var. abyssinicum genotypes from Northern Ethiopia using ISSR markers

Abstract

Pisum sativum var. abyssinicum is a globally important legume crop, and its genetic diversity is vital for crop improvement, sustainable agriculture, and biodiversity conservation. This study investigated the genetic variability and population structure of P. sativum var. abyssinicum genotypes from Northern Ethiopia using inter simple sequence repeat (ISSR) markers. A total of 120 genotypes from five geographically based populations were analyzed using 12 ISSR primers. Scorable bands ranged from 443 to 1298, with an average of 815.75 per primer. Primer UBC-880 (where UBC is University of British Columbia) produced the most bands (1298), while UBC-841 generated the highest number of polymorphic bands (421), indicating its effectiveness in detecting genetic diversity. Genetic analysis showed that 84% of variation occurred within populations, with only 16% between them, suggesting greater diversity among individuals of the same population. Factors like gene flow, mutation, and natural selection may contribute to this internal variability. The highest Nei's genetic distance (0.468) was observed between populations SET and R, suggesting strong differentiation, while the lowest (0.06) was between NW and SET, indicating close genetic similarity. Principal coordinate analysis (PCoA) revealed that the ST population was distributed across all three clusters, reflecting genetic similarities with other populations. Four genetically distinct clusters were identified using UPGMA clustering. South Tigray showed the greatest genetic variability. Despite its unique traits and historical importance, the genetic variability of P. sativum var. abyssinicum remains underexplored. This study provides essential insights for breeding and conservation, supporting the use of ISSR markers to guide genetic improvement and preservation strategies.