Variáveis morfológicas, estimativa de parâmetros e dissimilaridade genética em folhas de Castanheira-do-Brasil.

Abstract

The castanheira-do-brasil (Bertholletia excelsa Bonpl.) is characterized by being a large tree, its fruits and wood are marketed. However, there are few commercial plantations of Brazil nuts in the country, as it has little technological support for this practice and a long period to reach maturity. Therefore, this research aimed to carry out the morphological characterization of leaves in Brazil nut accessions in order to indicate descriptors according to their averages, parameters and genetic diversity. For this, leaf samples were collected from the accessions present in the Active Germplasm Bank of Embrapa, from the states of Pará and Amazonas. In this BAG, the design used was randomized blocks, with 16 accessions and two replications per plant, for measurements, 20 leaves of each plant were collected. Therefore, pre-established morphological descriptors were measured, namely: Limbal Length (CL); Limbo Central Width (LCL); Limbo Apex Width (LAL); Limbo Base Width (LBL); Petiole Length (CP); Number of Ribs (NN); Distance between Ribs (DN); Number of Secondary Vein Pairs (NPNS). After data collection, statistical analyzes were performed to observe leaf morphological differences between accessions, through descriptors. For this, Analysis of Variance and test of means were generated with the help of the Assistat 7.7 software and estimation of genetic parameters and genetic dissimilarity with the Rbio software. According to the significance value in the Analysis of Variance, heritability and accuracy in the genetic parameters, it was possible to observe the descriptors with results more related to the genetics of the species, which were CL, LCL, LAL, LBL, CP, NN, DN. Furthermore, considering all descriptors in the dendrogram, it was possible to obtain dissimilarity between eight groups.