Genetic Diversity in Yam Germplasm from Ethiopia and Their Relatedness to the Main Cultivated Dioscorea Species Assessed by AFLP Markers

Abstract

Yam (Dioscorea spp.) is widely cultivated in southern Ethiopia, where farmers maintain many named landraces. Nevertheless, little is known about their diversity and species identity. In this study, amplified fragment length polymorphism (AFLP) markers were used to investigate the genetic diversity in 48 yam accessions from Ethiopia, and to assess their relatedness to yam species commonly cultivated in West Africa such as D. alata L., D. bulbifera L., D. cayenensis Lam., and D. rotundata Poir. Ten AFLP primer combinations generated 900 fragments, of which 97% were polymorphic. Cluster and principal coordinate analyses revealed that the Ethiopian accessions are distinct from the Dioscorea species widely cultivated in West Africa. A separate analysis of the Ethiopian accessions gave six clusters that represented the various maturity groups and the nonflowering accession in the collection. Analysis of molecular variance (AMOVA) showed that 81% of the variation detected was found within collecting areas, while the variation among collecting areas contributed only 19%. The groups detected by AFLP markers were highly consistent with the local yam classification system and also reflected the main structure of morphological diversity.