Genetic diversity of yam (Dioscorea sp.) through morphological and molecular markers

Abstract The aim of the present study was to evaluate the genetic diversity of genotypes of Dioscorea sp. originating from states of the Brazilian Northeast region (Sergipe, Bahia, Alagoas, and Paraíba) through morphological and molecular characterization. For this evaluation, 52 yam genotypes were collected from market locations and directly from rural growers. Morphological characterization made use of 31 morphological descriptors for the yam crop. The environmental coefficient of variation (CVe) of most of the descriptors evaluated was greater than the genotypic coefficient of variation (CVg), and heritability was high only for stem color (86.86%). The highest significant positive correlation was between the presence of the tuber and the presence of roots on the surface of the tuber (r = 1; p < 0.001). The genotypes were clustered in seven different groups based on the morphological descriptors evaluated. For molecular characterization, SSR (9) and ISSR (16) primers were used. The primers used were considered informative, showing high polymorphic information content; and 100% of the bands were polymorphic. Genetic diversity was estimated by the following parameters: number of alleles (2.00), effective number of alleles (1.30), expected heterozygosity (0.211), and the Shannon index (0.351). The 52 genotypes were clustered in seven groups according to the Jaccard distance. The genetic structure of the population in K = 2 reveals shared alleles among the genotypes of different geographic origins. Morphological and molecular characterization reveals the high genetic diversity among the 52 genotypes of Dioscorea sp. and low diversity among the collection sites.