A PCR-based assessment of genetic diversity, and parentage analysis among commercial mango cultivars and hybrids

Abstract

Three different PCR methods [Random Amplified Polymorphic DNA (RAPD), Inter - Simple Sequence Repeats (ISSR), and Directed Amplification of Minisatellite DNA (DAMD)] were used to analyse genetic diversity and parentage among 20 mango cultivars, including 18 landraces and two hybrids (‘Amrapali’ and ‘Mallika’). These hybrids together with a third hybrid (‘Ratna’), and an out-group species (Mangifera sylvatica) were also analysed for parentage. Fifteen, seven and four primers were used to amplify a total of 158, 69 and 59 distinct DNA fragments by RAPD, ISSR and DAMD, respectively. Of these, approx. 85%, 64% and 90% were polymorphic, respectively. Genetic distances between pairs of mango cultivars were measured separately by each method and depicted graphically as a Neighbor Joining (NJ) tree. The three methods revealed different groupings of cultivars and hybrids. A NJ tree based on the cumulative data from all methods correlated well with the parentage of the mango hybrids, and the grouping of cultivars on a regional basis. Genetic markers likely to be associated with important agronomic traits were identified by further analysing the hybrids, with their respective parents, using all three methods. On the basis of the highest number of polymorphic bands observed (90%), DAMD was judged to be the best method with which to analyse mango germplasm.