Genetic diversity among East Asian accessions of the barley cove collection as revealed by six isozyme loci

Studies of allelic variations at six isozyme loci revealed genetic diversit y of 380 East Asian accessions of the Barley Core Collection. Genetic varia tion was found in both cultivars and landraces in different regions. Alleli c variations at the Aco-1 and Aco-2 loci were detected for East Asian barle y for the first time. Moreover, the Aco-l locus displayed the highest genet ic diversity among the six loci assayed. Indian cultivars showed the highes t diversity, followed by Korean and Chinese cultivars. Landraces from Bhuta n and Nepal showed the lowest diversity. Cultivars had generally higher div ersity than landraces within as well as among regions. The cluster analysis of genetic identity showed that all landraces from different countries can be placed in one group; the cultivars from Japan, India and Korea each for m independent groups. Gpi-1 Gu, Pgd-1 Tj, Aco-1 Si, Ndh-2 D and Aco-2 A wer e rare alleles found in only a few accessions of 6-rowed barley. The Pgd-2 Tn allele was very rare in East Asian accessions.