Diversidade genética em castanheira-do-gurgueia (Dipteryx lacunifera Ducke) com base em características físicas e químico-nutricionais do fruto

摘要

This study aimed to evaluate the genetic divergence among 23 "castanheira-do-gurguéia" genotypes based on fruit physical, chemical and nutritional characteristics. Fruits were collected from natural occurrence areas of the Piauí southwestern savannah. The physical characteristics analyzed were: (a) fruit - average mass (MMF), length (CF), width (LF), thickness (EF) and pericarp average mass (MMP); and (b) nut - average mass (MMC); length (CC), width (LC) and thickness (EC). The nut chemical and nutritional characteristics analyzed were: fat, crude protein, crude fiber, ash and total carbohydrates, all expressed in percentage; crude energy, expressed in kcal 100 g-1, and the minerals (P, K, Ca, Mg, Mn, Fe, Cu and Zn), expressed in mg 100 g-1. The genetic divergence was evaluated using Mahalanobis distance as dissimilarity measure and evaluated the relative importance of the characteristics in the genetic divergence. Tocher and UPGMA grouping methods were used. A high variability for these characteristics was observed among genotypes. The genotypes G-17 and G-18 are the most divergent and the genotypes G-3 and G-16 are the most similar. The characteristics that had the greater contributions to the genetic divergence among genotypes were MMP, MMF, E, FB, CT and PB. The "castanha-do-gurguéia" is richer in P, K, Mg, PB, FB, CT and E.