Genetic diversity as assessed by morphological and microsatellite markers in greengram (Vigna radiata L.)

Abstract

Genetic diversity in 20 elite greengram [Vigna radiata (L.) R. Wilczek] genotypes were studied using morphological and microsatellite markers. 18 morphological traits generated 50 alleles and the number of alleles ranged from two to five. 16 microsatellite markers from greengram, adzuki bean, common bean and cowpea were successfully amplified across 20 greengram genotypes of which 14 showed polymorphism. A total of 41 alleles were generated with an average of 2.56 alleles per locus. The number of alleles ranged from two to five. Similarity measures and clustering analyses were made using 91 alleles generated from morphological and microsatellite data. The resulting dendrogram distributed 20 greengram genotypes into six main clusters. The results of the principal component analysis were well congruent with the dendrogram. In the dendrogram as well as in the principal component analyses, genotype Vigna umbellata was placed separately from the rest of the genotypes. There was successful cross species amplification of adzuki bean, common bean and cowpea microsatellite or simple sequence repeat (SSR) markers in greengram. This study demonstrates that a combination of morphological and molecular markers increases the efficiency of diversity measured and the adzuki bean microsatellite markers are highly polymorphic and can be successfully used for genome analysis in greengram. Results indicate that sufficient variability is present in the greengram genotypes studied and would be helpful in the selection of suitable parents for breeding purposes and gene mapping studies.

Key words: Greengram, Vigna radiata, morphological markers, cross species amplification, microsatellite markers, genetic diversity.