Novas estratégias na avaliação do porte do feijoeiro

Abstract

In common bean, upright plants have been desired for a long time. For small farmers, growing upright plants is important because can avoid losses during harvest. On the other hand, for big farmers, it facilitates the harvest by allowing mechanization in large areas. However, getting this desired kind of plants is a challenge for breeders, since there are many genes under the control of this trait. Furthermore, commercial cultivars must have good grain appearance and quality, and high yield. For quantitative traits, like these, the best strategy is to apply recurrent selection, which is more efficient as the number of growing seasons is reduced to complete a selective cycle, i.e. selecting plants before flowering and crossing just the most upright plants. When doing this, it is necessary that the plant architecture at flowering reflects what will happen near harvesting. Thus, the aims of the present study was to verify if there is association between the plant architecture during flowering and harvest; to study the association among traits which are determinant to plant architecture and grain yield; and verify if there is progeny-by-environment interaction in these traits. The following traits were assessed: plant height, score for plant architecture at flowering and harvesting, hypocotyl diameter, grain yield and 100 grain mass. 62 progenies and 2 checks in generations S 0:2, S0:3 and S 0:4 were evaluated using the triple square lattice design, at three locations. Genotypic and phenotypic parameters for all traits were estimated from analysis of variance by using local and joint analysis. Also, correlations pair-wise among traits were estimated and used to calculate a selection index considering all traits assessed in this study. Afterward the correlated response was calculated for the traits based on the selection using the index. From the results, high estimates of correlation for plant height and plant architecture at flowering and harvest was observed. Moreover, there was low association between architecture plant score and grain yield. These results suggest some conclusions: it is possible to select upright plant architecture before flowering; plant architecture and grain yield are independently controlled; and there were non-significant progenies-byenvironment interaction for the traits associated to plant architecture score.