Cultivars identification and their genetic relationships in Dimocarpus longan subspecies based on RAPD markers

Random amplified polymorphic DNA (RAPD) analysis was employed to identify cultivars and the relationships between 22 morphologically more or less alike genotypes of longan ssp. Fifteen registered cultivars and seven exotic primitive cultivated forms of longan ssp. were used in this study. The 26 primers, selected from 87 initially screened, generated 190 bands of which 102 were reproducible polymorphic and size-separated from 480 to 2300 bp. These polymorphic RAPD markers distinguished 22 genotypes by at least six marker differences. The use of only 28 RAPD markers amplified by primers A39, C59, C62, F10, and F44 were sufficient to identify uniquely all the genotypes, indicating that RAPD markers are efficient for use in genetic fingerprinting in longan ssp. Jaccard's similarity between pairs of genotypes ranged between 0.554 and 0.930 with a mean of 0.672. The unweighted pair-group method using arithmetic averages (UPGMA) dendrogram indicated that 19 genotypes were classified into two major groups. Each group was divided into two subgroups. Most of the genotypes developed/registered from the same country or same breeding center clustered very closely. One Taiwan cultivar ‘Fungkok’, one Chinese cultivar ‘Fuku Yan’, and one exotic primitive cultivated form ‘Malay’ from Malaysia were independently distant from the 19 genotypes of the two main groups. This information would be helpful for future genome mapping programs as well as for the application of intellectual breeder.