Validation of genome-data based simple sequence repeats for ascertaining hybridity in mango (Mangifera indica) hybrids

Abstract

The present study was carried to identify polymorphic SSRs derived from the whole draft genome data of mango (Mangifera indica L.) for their polymorphism between Amrapali and Sensation genotypes (parents) and their validation on the derived hybrid progenies. Fifty new hypervariable mango SSRs (HMSSRs) were screened against the parental genotypes. Out of which, 11 HMSSRs were polymorphic, 18 were monomorphic and 21 did not amplify at all. These polymorphic HMSSRs were then used for ascertaining the hybridity of the hybrid progenies. The genetic diversity indices of each SSR locus among mango hybrids were calculated using Power Marker ver. 3.25. The genetic diversity indices such as the number of alleles ranged from 2 (HMSSR35) to 5 (HMSSR57), gene diversity from 0.36 (HMSSR54) to 0.71 (HMSSR57 & HMSSR58), and PIC values from 0.35 (HMSSR69) to 0.66 (HMSSR57). The dendrogram generated using Neighbor joining tree divided the 22 genotypes into three distinct clades, viz. Clade ‘A’, Clade ‘B’ and Clade ‘C’. The hybrids, viz. H-3-1, H-3-2, and H-7-4 were identified as true hybrids, since they were genetically more close to female parent (Amrapali), while hybrids H-3-3, H-3-11, H-11-1, H-12-5, H-1-6, H-1-13, H-12-8, H-12-10, H-3-12, H-1-1 and H-4-10 were more close to the male donor parent (Sensation) and also had red peel colour. In the present study, the 20 hybrids were confirmed to be the true hybrids since the bands unique to the two parents were present in them.