In this study, the objective was to evaluate the intra and interspecific genetic diversity of 21 accessions of two pitaya species, Hylocereus undatus (Haw) Britton & Rose and Selenicereus setaceus Salm-Dyck. A. Bereger ex Werderm., using the physical and chemical characteristics of the fruits. The characteristics evaluated were length, diameter, soluble solids, total peel and pulp weight. Based on these characteristics, genetic distance index between each pair of accessions were calculated using standardized mean Euclidean distance. From the genetic distance matrix, cluster analysis by dendrogram and graphic dispersion by multidimensional scaling were performed. The characteristics showed different relative contributions to genetic diversity. The fruit diameter was the variable that contributed most for the genetic diversity index (27.45 %), followed by the total mass of the fruit (24.43 %), and mass of fruit pulp (24.67 %). The genetic distances between the 21 pitaya accessions ranged between 2.2 and 540.1. Cluster analysis subdivided 21 accessions in two genetic similarity groups, Hylocereus e Selenicereus, at a genetic relative distance of 100. The physical and chemical characteristics of the fruit showed high genetic diversity among accessions of the species H. undatus and S. setaceus.
Cactaceae; Hylocereus undatus; Selenicereus setaceus; genetic variability
