Genetic variability and relationship studies in new Indian papaya (Carica papaya L.) germplasm using morphological and molecular markers

Papaya germplasm showed wide morphological diversity in terms of fruit yield, weight, length, cavity, fruiting zone, flesh thickness, flesh color, and total soluble solids content. RAPD and ISSR markers also showed polymorphisms at rates of of 84.32% and 84.67%, respectively. Jaccard's genetic similarity values of RAPD and ISSR were found in the range of 0.30-0.99 (average: 0.65) and 0.26-0.95 (average: 0.61), respectively, suggesting a moderate level of genetic diversity within the papaya group. Seven of the 15 RAPD primers and 5 of the 11 ISSR primers were also able to generate cultivar-specific amplicons, which were used for identification of germplasms Lalima, Madhu, PS-3, Farm Selection H, CO-7, and PSR-1-11. A dendrogram based on UPGMA separated all the selections into 4 main clusters, in which 3 genotypes, Lalima, Madhu, and PS-3, were found to be superior to the rest of the papaya germplasms. A two-dimensional plot generated from the principal component analysis of RAPD and ISSR data also supported the clustering pattern of the dendrogram. The present study revealed that morphological and molecular markers may be successfully utilized for determining genetic diversity and genetic relationships in papaya groups and may be used successfully in papaya breeding programs.