AFLP-based assessment of genetic variation in Indian elite cultivars of Cymbopogon species

Abstract

\n Cymbopogon, one of the major aromatic genera of Poaceae family, is mainly cultivated for its essential oils that hold promising medicinal and commercial value. In India, several improved cultivars of Cymbopogon species are developed for commercial cultivation and conceded by means of agronomic and chemotypic traits. Information on genetic variability in these commercial cultivars is still limited which poses a problem in further improvement of oil grasses. The present study aimed to investigate the genetic variation among certain improved Indian cultivars of three commercially important Cymbopogon sp. i.e., C. flexuosus, C. winterianus and C. martinii using amplified fragment length polymorphism (AFLP) markers. A total of 94 robust loci were amplified using 8 AFLP primer combinations. Among the total amplified fragments, 72 were polymorphic which showed 76.59% polymorphism across all the germplasm. Polymorphic information content (PIC) and marker index (MI) values showed significant positive correlation (r2 =0.94, p< 0.005) in determining the discriminatory power of the AFLP primer combinations. A higher effective multiplex ratio (EMR) and MI values were recorded for the primer combinations that generated higher polymorphism across the genotypes. To obtain the genetic information at the intra-and inter species level, genetic diversity indices were calculated. Genetic heterogeneity was noticed in the order C. martinii>C. flexuosus>C. winterianus. UPGMA-phenogram and principal coordinate analysis (PCA) separated all the cultivars as per the chemotaxonomic series with a few exceptions. Molecular diversity explained and diagnostic fragments developed through AFLP markers in this study could provide a detailed cataloguing of Cymbopogon cultivars for genetic conservation purpose and also useful for exploration and improvement of diverse set of germplasm.