Microsatellite analysis of intracultivar diversity in ‘Chinnarasam’ mango from Andhra Pradesh, India.
‘Chinnarasam’, a juicy cultivar of mango (Mangifera indica L.), is among the most important mangoes of an Indian State of Andhra Pradesh, whose production and quality is variable across the State. Twenty accessions of ‘Chinnarasam’ (CR Acc-l to CR Acc-20) were selected from 9 locations spread over 6 districts, representing all the three eco-geographical regions (Coastal Andhra, Rayalaseema and Telangana) of Andhra Pradesh. Their leaves were sampled to study intracultivar diversity following microsatellite analysis. The dendrogram generated based on unweighted pair group mean with arithmetic average, showed three major groups of accessions, which followed geographical separation. Twenty out of 109 mango-specific micro satellites validated, were polymorphic (18.34%). Microsatellites produced a total of 62 alleles, of which 31 were polymorphic (50%). The Jaccard’s similarity coefficient ranged from 0.54 to 1.00. Existence of intracultivar genetic diversity (up to 46%) indicates that ‘Chinnarasam’ whatsoever cultivated throughout the State is not a pure clone, which allows the genetic breeding of this cultivar by means of mass selection. Microsatellite markers have proven useful in assessing intracultivar genetic diversity and identifying accessions of ‘Chinnarasam’ cultivar.
Key Words: Eco-geographic survey, genetic diversity, genetic relationship, SSR markers