Genetic diversity of Ethiopian potato (Plectranthus edulis (Vatke) Agnew) genotypes using simple sequence repeat markers

Plectranthus edulis is among the most ancient and native tuber crops in Ethiopia, which is mainly cultivated by smallholder farmers. Being an orphan crop, it has not received due research attention. To tackle major crop-production constraints through breeding, knowledge of its genetic diversity is a prerequisite. Thus, the current study was carried out to assess the nature and extent of genetic diversity in 130 genotypes using 20 cross-transferable expressed sequence tag-simple sequence repeat (EST-SSR) markers developed from a related species, Plectranthus barbatus. Among the 20 SSR markers, 15 were transferable to Plectranthus edulis, from which 14 polymorphic markers were used for diversity analysis. A total of 101 alleles were detected, with a mean of 7.2 alleles per locus. Allele frequency ranged from 0.23 to 0.54, with mean value of 0.40. Polymorphic information content (PIC) ranged from 0.54 to 0.84, with a mean of 0.70, indicating a high level of informativeness. The Nei’s genetic distance ranged from 0.026 to 0.247, with the highest similarity being between Wolaita and Gamo Gofa populations. About 97% of the genetic variation was attributable to differences within populations; only 3% was attributable to variation among populations. The Neighbor-Joining cluster analysis grouped the 130 genotypes into three clusters. In general, the EST-SSR markers were effective in identifying genetic diversity in Ethiopian potato. This information can help to identify parental lines for crossing and exploiting the existing variability through selection.