Estimativa de parâmetros genéticos, diversidade genética e métodos de seleção em progênies de soja

Abstract

In soybean breeding programs aimed at obtaining new cultivars with superior attributes, it is necessary to evaluate the genetic potential of the genitors, as well as estimating the genetic parameters and choosing the selection method essential for developing superior soybean cultivars. This dissertation is divided into three chapters. Thus, the first chapter is made up of the theoretical framework, which presents information about soybean cultivation, genetic improvement, the choice of genitors and diallels, estimates of genetic parameters and selection strategies. In the second chapter, the aim was to determine the general and specific combining abilities of five soybean parents, using a partial diallel, in order to detect the parents and hybridizations that showed superior results for soybean earliness and grain productivity. The trials were carried out at the Capim Branco Experimental Farm of the Federal University of Uberlândia in the Soybean Genetic Improvement Program. 15 genotypes were evaluated, 10 F2 progenies originating from a diallel cross and 5 parents (UFUS7910; UFUS8301; BRS7481; BRS7380RR and BRS 7980). Through diallel analysis, it was observed that the parents BRS7481 and BRS7380RR contribute to greater precocity, while UFUS7910 UFUS8301 contributes to greater grain productivity, therefore, they were considered genetically superior and recommended to participate in crosses. The most promising combinations for grain productivity and agronomic traits were UFUS8301 X BRS7980 and UFUS7910 X BRS7380RR. The third chapter aimed to estimate genetic parameters and evaluate agronomic traits in 22 segregating RCF3:4 soybean populations and select superior progenies for precocity and productivity, also evaluating 14 agronomic traits