Genetic divergence in Cordia trichotoma progenies in a multiple cropping system with Dalbergia nigra

Abstract

Cordia trichotoma is a Brazilian species that has been studied for different forest systems. However, genetic breeding programs could highly improve species use. To obtain a better yield, it is essential to identify the species genotypes with superior performance. Thus, the work objective of this work was to estimate genetic divergence in two C. trichotoma progenies tests based on phenotypic traits. The experimental design adopted was the randomized blocks, one plant per plot, using 40 (area one) and 34 (area two) repetitions, using 3.0 m x 3.0 m spacing. The evaluated traits were diameter at 1.30 m above the soil (DBH-cm), total height (HT-m), collar diameter at 30 cm above the ground (DC-cm), and height of the first whorl (HFW-cm). The estimate of genetic divergence and the Tocher clustering method was performed using the REML / BLUP method. The genetic distances between the progenies in area 1 were 2.13 and 47.74 (17 and 15). In area two the genetic distances between the progenies were 3.64 (9 and 15) and 48.28 (12 and 7). The progenies formed 10 and 4 distinct groups, respectively, in area 1 and area 2). The traits that most contributed to genetic divergence were DBH-2016 (14.65%) in area one, and HT-2014 (14.32%) in area two. In sumary, the C. trichotoma progenies show high genetic divergence. Regarding breeding programs, it is recommended to cross progenies from the most divergent groups to heighten the genetic gain through the selection of more productive genotypes.