Molecular diversity and association of simple sequence repeat markers with bud necrosis disease in interspecific breeding lines and cultivars of peanut (Arachis hypogaea L.)

Abstract

Molecular markers are useful tools for assaying genetic variation and provide an efficient means for early and reliable selection of genotypes having resistance to peanut bud necrosis disease (PBND) in peanut breeding programs. Molecular diversity and association of simple sequence repeat (SSR) markers with resistance to PBND was detected in 21 interspecific pre-breeding lines and three cultivars of peanut differing in degree of resistance to PBND. Forty-five primer pairs yielded a total of 531 fragments, of which 337 were polymorphic, with an average of 7.5 polymorphic fragments per primer. Polymorphism ranged from 0 - 100% with an average of 60.2%. Cluster analysis (UPGMA) revealed two main clusters separated at 77% Jaccard’s similarity oefficient based on resistance to PBND. All 14 susceptible lines were grouped into a single cluster, while 11 resistant lines grouped into a separate cluster. AMOVA among 24 lines detected 43% (P < 0.001) of total variation associated with resistance to PBND. Kruskal-Wallis ANOVA detected the significant association of 16 primers with resistance to PBND. Nine out of 16 primers explained more than 10% of phenotypic variation due to resistance to PBND. It appears that these loci are associated with the resistance to PBND in peanut and major QTLs with regression coefficient value (r2) ranging from 10.1% to 77.5%. Of which PM15190, PM188165 and PM201130 loci effectively differentiated most of the resistant lines from the susceptible lines.