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Evaluation of genetic diversity in nine species of Cattleya using RAPD and ISTR molecular markers

Abstract:

Genetic diversity of nine species of Cattleya spp. collected in Venezuela was studied using RAPD and ISTR molecular markers. Out of 49 RAPD primers initially used to identify polymorphic markers, only 19 showed higher resolution and number of discriminative polymorphic bands in agarose gels. Two-hundred fifty-five-bands were generated, from which 158 were polymorphic. For ISTR, information was obtained for four out of five combinations used in this study, thus generating 101 fragments, 42 of which were polymorphic. UPGMA cluster analysis of RAPD data using Jaccard distance found four discriminant groups, the first consisting of C. lueddemanniana and C. lawrenceana, the second by C. percivaliana, the third by C. mendelii, C. violacea, C. trianaei and C. mossiae, and the last by C. jenmanii and C. gaskelliana. ISTR data analysis yielded three groups, the first consisting of C. mendelii, C. trianaei and C. lawrenceana, the second by C. lueddemanniana, C. jenmanii and C. percivaliana, and the last by C. mossiae, C. gaskelliana and C. violacea. Molecular analysis of the nine species of Cattleya showed a high diversity among them based on the presence of different molecular banding patterns obtained using both marker types, and generated groups based on flower color and plant habitat. Given that RAPD patterns showed higher number of polymorphic bands, they were more informative than those based on ISTR combinations.