Genetic diversity and discrimination of mango accessions using RAPD and ISSR markers

Abstract

Forty six mango cultivars were screened using RAPD and ISSR markers. Nine decamer oligonucleotides and 11 inter simple sequence repeats yielded 110 and 160 discrete fragments, respectively. RAPD primers yielded 14 monomorphic bands and 96 displayed polymorphism. Percent polymorphism generated by these primers was 87.3%. OPA 19, OPA 20 and OPC 6 were highly polymorphic primers. Overall polymorphism detected by ISSR was 79.38%, 14.5 bands per primer. ISSR 5 yielded 14 polymorphic bands and 7 monomorphic bands. UPGMA tree constructed on RAPD data on the basis of Jaccard's coefficient clustered the accessions into 3 groups, one comprising majority of north Indian varieties and other having eastern Indian and third cluster comprising accessions from both the regions. UPGMA clustering of ISSR data could not arrange the cultivars as per geographic separation. Cumulatively band data from these two methods precisely arranged accessions from two ecogeographical regions in such a way that interrcultivar affinities were congruent with our understanding of the group. Since geographic distance between East Indian and North Indian genotypes is very less, it is logical to have overlapping. No clear cut separation among varieties from two regions supports the common gene pool origin as well as operation of similar selection pressure as the cultivar preferences in these areas are largely same.