Morphological and Microsatellite Analysis of Intravarietal Heterogeneity in ‘Beneshan’ Mango (Mangifera indica L.)

Abstract

'Beneshan' is the choicest table cultivar of mango (Mangifera indica L.) that has been under cultivationfor more than a century in Andhra Pradesh state, India. Through an eco-geographic survey covering thethree regions of the state, 31 accessions of 'Beneshan' (BN Acc-l to BN Acc-31) were selected and theirfruit and leaf samples were collected to study intracultivar heterogeneity based on morphological fruittraits and microsatellite markers, respectively. In-situ characterization and evaluation of fruit samplesrevealed phenotypic variations among 'Beneshan' accessions. Of the 109 mango-specific simple sequencerepeats (SSRs) validated, 23 were polymorphic. Polymorphic microsatellites produced a total of 58alleles, of which 30 were polymorphic (51.72%). The polymorphic information content values variedfrom 0.03 (SSR-59) to 0.72 (SSR-87). Highly polymorphic microsatellites like SSR-80, SSR-87, SSR-28,and SSR-89 were more useful in differentiating the 'Beneshan' accessions. Microsatellites SSR-91 andMngSSR-26 produced unique alleles of 280 and 140 bp in BNAcc-8 and BNAcc-9 accessions,respectively. Jaccard’s similarity coefficient varied from 0.50 to 1.00. There was a wide range ofintravarietal heterogeneity (up to 50%) indicating that 'Beneshan' whatsoever cultivated throughout thestate is not pure clone, which allows the genetic breeding of this cultivar by means of mass selection.