Estimativas de parâmetros genéticos para seleção em teste de progênies aos quatro anos de Tectona grandis

Abstract

Teak (Tectona grandis) is a species recognized worldwide for its high-quality hardwood. In Brazil, both productivity and age of rotation show results superior to other countries. However, studies related to the genetic improvement are still scarce and genetic tests are necessary to understand the genetic variation of the species in Brazil, besides making it possible to select new clones developed and adapted to the edapho-climatic conditions. This work aimed to estimate genetic parameters and to practice the selection of genitors and individuals in a progeny test of T. grandis with four years. The test of half-sibling progenies was installed in January 2019 in the municipality of São José dos Quatro Marcos, Mato Grosso. The experiment was installed in incomplete block design with 19 treatments, nine blocks, 8 plants per plot and spacing of 3.8 m x 3.8 m. At four years, diameter at breast height (DBH), total height (TH) were measured and the mean annual increment (MAI) was estimated. Data analyses were performed using the software Selegen. The effect of progenies was significant at 1% and 5% significance for the three variables analyzed. The individual heritability was 0.3986 for Ht, 0.6329 for DBH and 0.7591 for MAI. The average heritability of progenies was 0.8348 for Ht, 0.9296 for DBH and 0.9377 for MAI. For accuracy, the values were 0.9137 for Ht, 0.9641 for DBH and 0.9684 for MAI. Genotypes superior to commercial clones were found for all traits studied. The gain with the selection of the 50 best individuals was 13.7% for Ht, 19.8% for DBH and 65.9% for MAI and with the selection of the eight best genitors were 9.01%, 10.53% and 27.64%, respectively. There were gains with de selection of genitors and individuals (potencial clones), with the B12 genotype and its descendants standing out