Assessment of Genetic Diversity and Identification of Informative Molecular Markers for Germplasm Characterization in Caribbean Stylo (Stylosanthes hamata)

Caribbean stylo (Stylosanthes hamata) is a tropical fodder and cover crop. Along with four other Stylosanthes species (S. scabra, S. humilis, S. viscosa, S. guianensis), it was introduced in India. It became well adapted in certain parts of the country and has been recommended for the improvement of range and degraded lands. A collection of 63 S. hamata accessions was fingerprinted with RAPD, ISSR and STS markers. Though the mean discriminating power of these marker systems ranges from 0.65 to 0.71, high values of marker index (2.91), resolving power (14.92) and effective number of patterns per assay unit (50.65) makes ISSR as a better marker system in comparison to other two markers used in this study. Thirteen RAPD and eleven STS primers could differentiate a maximum of 42 and 17 accessions, respectively, whereas two ISSR primers produced distinct fingerprints of all the S. hamata accessions. Mean genetic similarities of accession ranged from 0.83 (ISSR) to 0.91 (RAPD). Two RAPD, two STS and four ISSR primers generated a set of 12 diagnostic markers which could be useful for germplasm characterization and management.