Genetic diversity study in papaya (<em>Carica papaya</em> L.) cultivars using RAPD and ISSR markers

Abstract

Thirteen papaya cultivars and lines were used to assess genetic diversity through dominant PCR based markers (16 RAPD and 12 ISSR primers). RAPD (random amplified polymorphic DNA) primers gave 58 polymorphic bands out of 126 with 47.19% polymorphism and ISSR (Inter simple sequence repeats) primers produced 49.80% polymorphism with 37 polymorphic bands out of 65 bands. Dendrogram showed clear grouping ancestrally related papaya cultivars. Principle coordinate analysis (PCoA) showed congruence with dendrogram pattern while bootstrap values at major nodes in both marker systems as well as in pooled data indicated robustness of cluster pattern in dendrogram construction. Analysis of molecular variance (AMOVA) indicated that highly significant genetic variability was obtained through both marker systems while cultivars showed noticeable variation in case of RAPD markers. Mantel’s test between similarity and cophenetic coefficient matrices in different combination showed poor to very good correlation between matrices. This study indicates relation between papaya cultivars based on their ancestral relationship which can be utilized for conservation of important cultivars and development of future strategies for crop improvement programme.