Progênies precoces e tardias de soja de um mesmo background genético

Abstract

The high yield performance of soybean cultivars is attributed to the genetic improvement of soybean in Brazil, due to the breeding programs. Many interested traits of are considered in combination for the genotypes selection and full new cultivars. Release are widely studied by researchers and specialists in soybeans, as maturity and yield. Once the Brazilian agricultural crop system, allows the growth of a succession crop in the same agricultural year, and in this scenario the short cycle varieties are important to optimize the system. Thus, it is expected that soybeans present in addition to good performance, early full maturity, what means, short cycle what meets the growers demands to optimize the production system. These are quantitative traits. As late is the crop cycle as better is the yield performance, however, recent studies related to the crop cycle, shows that it is possible to select high grain yield associated with early maturity. In this way, we aim to estimate genetic and phenotypic parameters, to obtain information on the association between traits related to full maturity and yield performance. To study and compare early-maturity progenies (PP) and late-maturity progenies (PT) from the same genetic background. The trials were carried out in Lavras-MG and Ijaci-MG, in the spring-summer 2018/2019 crop season. The evaluated traits were yield (PROD), days for flowering (DPF), cycle (DPM), vegetative period (PV), reproductive period (PR), a relation between reproductive and vegetative period (PR/PV) and daily yield increment (IDP). The estimated parameters were 𝜎̂𝐺2, 𝜎̂ 𝐴2 e 𝜎̂𝐺 𝑥 𝐴2, genetic correlations, expected gains with selection, correlated response, relative maturity group, as well as BLUPs means for the considered traits. Variability is available between progenies for all traits, except for the PR/PV ratio, allowing the selection of improved lines. In the contrast between PP and PT varies by some traits. The PP vs PT contrast, shows distinct behavior between the two groups. Genotype x environment interaction (G X A) is observed for the traits in all sources of variation. There is a positive and significant association between the traits DPM, PR and a PR/PV ratio for yield. The selection of the early maturity progenies also results in reduced expression of the traits DPF, PV and DPM, PR, a PR/PV ratio and yield. The mean BLUPs intervals shows genetic variation between PP and PT, mainly for the traits PR, DPM and relative maturity group. There is no average difference between the PP and PT group for IDP well as the PR/PV ratio with the high yield.