Importância de caracteres morfoagronômicos no guaranazeiro por componentes principais

Abstract

Studies of genetic diversity have been of great importance in breeding programs for reporting parameters identification of parents that allow large heterotic effect and more likely to recover superior genotypes in the progenies. Therefore, this study aimed to examine the implications of using the analysis of important characters in the elimination of traits evaluated for calculating the genetic distance in clones of guaranazeiro. The experiments were conducted in the municipalities of Iranduba, Manaus and Maués for six years, where 32 clones of guaraná were observed. The experimental design was randomized blocks with two repetitions and plots of three plants in 5 m x 5 m spacing. The variables evaluated were fruit production (PROD), number of branches per plant (NR), main branch length (CR), main branch diameter (DR) and number of leaves (NF) per plant at 12 months of age. Data were subjected to analysis of variance with fixed effects and means were compared by Scott-Knott test at 5 % of probability. Subsequently, the average Euclidean distance was calculated as standardized measure of the relative importance of the characters, which was estimated by the participation of components for each trait, the total dissimilarity observed and for the grouping of clones, we used the method of Tocher. The results suggest that there is a low genetic divergence among 32 clones, however, there is a large genetic variability. The first two principal components (PROD and NR) explained 80.79 % of variability, which are those that contributed most to the divergence. The NF was the variable that contributed least to the divergence and, therefore, subject to disposal.