Exploring the molecular diversity and population structure of Ethiopian and exotic lentil (Lens Culinaris Medikus) germplasm

Exploring molecular diversity of lentil is essential for designing effective breeding strategy and management of lentil genetic resources. However, there is very limited molecular study on the Ethiopian lentil gene pool. Hence studies were undertaken to assess the molecular diversity and infer the population structure of Ethiopian landraces, improved varieties, and introduced germplasm using SNP markers. After the analysis of multiple diversity indices on 187 lentil germplasm using 2121 filtered quality DArTseq SNP data, introduced germplasm exhibited higher genetic diversity and broader allelic composition, highlighting its strong potential benefit for use in breeding programs. In contrast, landrace populations showed very limited diversity, reflecting a genetic bottleneck. Analysis of molecular variance (AMOVA) and hierarchical clustering based on FST demonstrated significant genetic differentiation between introduced and landrace germplasm, confirming restricted gene flow between these groups. Deviations from Hardy-Weinberg expectations, characterized by excess homozygosity across populations, reflected both the predominantly self-pollinating nature of lentil and the way lentil is processed during varietal development. Principal component analysis, clustering and population structure modeling, consistently depicted two major population groups, separating landraces from introduced accessions. However, improved varieties were a mixture of both populations highlighting the importance of both populations for lentil varietal development in Ethiopia. The landrace lentil germplasm showed a very narrow genetic base and hence the findings of this study underscore the importance of introduced germplasm for broadening the breeding base while emphasizing the need to conserve and enrich local landrace diversity.