Genetic diversity of nine faba bean (Vicia faba L.) populations revealed by isozyme markers

Abstract

Seven isozyme systems (Sod, 6-Pgd, Me, Est, Skdh, Fdh and Gdh) representing nine loci were used to study the genetic diversity of nine faba bean populations. Seven loci revealed polymorphic bands and showed the same quaternary structure as that found in several species. They revealed a high number of phenotypes. Indeed, from 3 to 9 phenotypes per locus were investigated in this study. The percentage of polymorphic loci (P = 59.3 %) was higher than that mentioned in the autogamous species (P = 20.3 %) and less than the optimum (P=96 %) indicated for allogamous plants. Total genetic diversity (H T) and within population genetic diversity (H S) were estimated with the isozyme markers. The contribution of among population genetic diversity (D ST) to total genetic diversity was 22%. Enzyme markers pointed out an average inbreeding level for whole population (F IT) and within population (F IS). Within population genetic diversity represents 78% of total diversity. Intra-population genetic diversity (H S = 0.206) was ranged with the respect of allogamous species and was clearly higher than that of among population genetic diversity (D ST = 0.057) indicating an out-crossing predominance in the studied populations. The expected heterozygosity was higher than that observed heterozygosity at the allogamous species was confirmed in this study. Although, the mean estimated gene flow was less than 1(Nm=0.814), the dendrogram based on Nei’s genetic distance of the 9 populations using UPGMA method showed some genetic drift between populations.