Genetic structure analysis of Fusarium oxysporum f. sp. phaseoli populations on common bean by using SSR markers

Determination of the genetic structure of the Fusarium oxysporum populations provides different levels of pathogen behavior and environmental compatibility in the management of root rot disease in bean farms. In this study, Short Sequence Repeat (SSR) markers were used to determine the genetic structure and estimate genetic diversity in sixty F. oxysporum isolates from five counties in Ilam province located in the west of Iran (Ilam, Ayvan, Malekshahi, Sirvan, Chardavol). A set of five microsatellite primer pairs revealed one allele in each locus across the populations. The average number of alleles (Na) and the mean number of effective alleles (Ne) observed among populations were 1.484, and 1.438 respectively. The number of Genetic diversity (H) and Shannon's coefficient (I) were also maximum in Chardavol (He = 0.442, I=0.333) but the minimum values were estimated in Ilam (He = 0.228, I = 0.333). The minimum genetic distance was found between Ayvan and Malekshahi (0.046) but the maximum genetic distance (0.151) was revealed between Ilam and Chardavol. The total gene diversity (Ht) and genetic variability between the subpopulations (Hs) were estimated to be 0.312 and 0.261, respectively. Gene diversity attributable to differentiation among the population (Gst) was 0.162, while gene flow (Nm) was 0.5717. Cluster analysis based on UPGMA showed the lowest genetic distance between Ayvan and Malekshahi. The dendrogram showed a clear break between the population from Sirvan and Chardavol and other remaining populations. Results from this study could be useful in breeding programs for developing root rot resistant cultivars.