Estimativa de parâmetros genéticos e ganho de seleção associados à viabilidade genética no melhoramento de Coffea canephora pela estratégia de seleção recorrente

Abstract

Coffee is a strategic crop for Brazilian agribusiness. The state of Espírito Santo stands out in the national coffee sector, occupying the second position in production and the first for the Coffea canephora species (conilon/robusta). Given the economic and social importance of this crop, Incaper started the genetic improvement program for conilon coffee in 1985 based on different strategies and lines of research. One of the strategies used is recurrent selection to improve populations and obtain recombined progenies, with the goal of gradually increasing the frequency of desirable alleles, without significantly reducing the genetic variability, essential for the productive sustainability of the species. This work aimed to evaluate the agronomic performance, selection gains, and genetic divergence of 56 hybrid progenies from the first recurrent selection cycle of a late-maturing population (PMT 01), together with six parents. Initially, it prepared the mother plants of selected progenies and parents for sprouting and production of clonal seedlings. The 62 genetic materials were evaluated in two environments, in the Experimental Farms of Marilândia and Sooretama, in a randomized block design with three replications, five plants per plot, and a spacing of 3.0 x 1.0 m. Fourteen agronomic characteristics were analyzed, referring to the evaluations of the first three crops, which occurred in the years 2019, 2020, and 2021. The estimates of the genetic parameters obtained by the mixed linear model methodology (REML/BLUP) revealed the existence of genetic variability and selective potential between the conilon coffee genotypes for the studied characters. With the ranking using the selection index by the Mulamba and Mock method and additive, selection gains above 77% and 16%, respectively, were observed, making it possible to select at least 17 hybrid progenies with the potential to be used in the composition of new cultivars (clonal and /or seed). In the grouping of genotypes using the Tocher optimization method, there was genetic variability among parents and among progenies from the intrapopulation recurrent selection method.