Divergência genética em coleção didática de batata-doce por descritores morfológicos

Abstract

Sweet potatoes are one of the most important food crops in the world. In the Northeast of Brazil, it is the main vegetable consumed and is a source of energy food. Because it is a tropical and subtropical climate plant, it is easy to grow and adaptable, presenting low production costs due to its rusticity. Brazil presents a diversity of types and forms of sweet potato, and part of its territory may be considered as a secondary center of variability of the species: hence the need to characterize and evaluate this culture. Therefore, the objective of this work was to evaluate the genetic divergence of sweet potato accesses belonging to the Germplasm Didactic Collection of the Federal Rural Semi-Arid University (UFERSA) using morphological descriptors. For the characterization, 21 accessions were used. The spatial arrangement in the field was in continuous rows (1.0 m between ridges and 0.3 m between pits, two branches per pits). We used 17 morphological descriptors: leaf color (mature and immature), general leaf profile, number of leaf lobes, leaf lobe types, central leaf lobe shape, pigmentation and petiole length, commercial root, commercial length and diameter of commercial roots, mature leaf size, film color. The hierarchical groupings of the accessions were obtained by UPGMA methods. The joint analysis of the qualitative and quantitative data to determine the genetic distance was accomplished with basis on the Gower algorithm. The relative contribution of the quantitative descriptors to the genetic divergence between the accessions was determined. In the generated dendrograms, there was distribution of the accesses in four distinct groups. The variables that contributed most to the genetic divergence among the accessions were commercial root (62.10%) and commercial root length (27.66%). Through morphological descriptors, it was possible to identify genetic divergence among the accesses of sweet potatoes belonging to the Didactic Collection of Germplasm of UFERSA