Amplified Fragment Length Polymorphism Marker-Based Genetic Diversity in Tamarind (Tamarindus indica)

Abstract

Tamarindus indica, commonly called tamarind, is a medium-sized evergreen tree that gives a high yield. The fruit is commonly used as a spice. Despite its commercial importance in the international market, it has been little explored. The genetic diversity and genetic relatedness of 36 tamarind genotypes were studied using amplified fragment length polymorphism (AFLP) markers. Twelve primer pairs were used for the screening of genotypes based on the number and quality of polymorphic fragments produced. These primer combinations produced 702 bands, 627 (89.3%) of which were polymorphic. The mean Nei's gene diversity index was 0.4868, and the Shannon's information index was 0.6802, indicating the abundant genetic diversity within the tamarind population. Among the tamarind genotypes, the dissimilarity coefficient ranged from 4.4 to 14. Cluster analysis grouped all tamarind genotypes into two major clusters (A and B) at 37 linkage distance and two minor clusters each. Cluster A included the genotypes predominantly with brown to dark brown fruit pulp and dark green leaves. However, the straight to semi-curved fruits were sub grouped in sub-cluster ‘A1’ and semi-curved to curved fruits in sub-cluster ‘A2’. Cluster B contained a collection of genotypes predominantly characterized with trees of orthotropic growth and semi-curved fruit shape. A good correlation of these amplified fragment length polymorphism-based groupings with their morphological traits was observed. We found moderate genetic diversity in these tamarind genotypes. The use of AFLP markers and the level of genetic variability detected within Southern Indian tamarind germplasm suggested that this is a reliable, efficient, and effective marker system that can be used for diversity analysis and subsequently in tree breeding programs.