Simultaneous recurrent selection for some characters in common bean / SeleÃÃo recorrente simultÃnea para alguns caracteres do feijoeiro

AUTOR(ES)

Josà Ãngelo Nogueira de Menezes JÃnior

DATA DE PUBLICAÇÃO

2007

RESUMO

The objective of this study was to estimate the genetic progress (GP) after three recurrent selection cycles to develop common bean lines that present a high yield, good architecture as well as commercially acceptable grain. The base population was derived from ten intercrossed lines of upright plant habit. The progenies in each cycle were evaluated over three generations S0:1, S0:2 and S0:3 on the experimental field of the Department of Biology at the Federal University of Lavras (UFLA), in Lavras, MG, in a lattice design. The following traits were evaluated: grain yield, plant architecture and grain type, the two latter by a grade scale. Analyses of variance and the estimates of genetic and phenotypic parameters were obtained for all progeny evaluations. The three traits were considered simultaneously in the selection of the best progenies for recombination or continuity of the breeding process. The GP was estimated based on the means of the ten best S0:1 and S0:2 progenies used in the recombination process in each cycle. The progress per trait was estimated and, upon standardization of variables, the progress for the three traits simultaneously. Since the cycles occurred in different years, the performance of two lines that participated in all evaluations was used as base to lessen the environmental effect in the estimates. The difference between the bâs of the linear regression, of the number of cycles, the independent variable (x), and the mean performance of the trait under selection, the dependent variable (y), of the progenies and of the controls, provided the estimate of the genetic progress. In conclusion, after three recurrent selection cycles the GP was 3.1% per cycle, considering the three traits simultaneously. This result proved the efficiency of the recurrent selection to obtain high-yielding lines of upright plant habit and standard carioca-type grains. The existence of genetic variability in the progenies for the three traits, especially in the last cycle, suggests the possibility of continuous success under recurrent selection.

ASSUNTO(S)

bean melhoramento vegetal regressÃo linear progresso genÃtico genetic progress feijÃo linear regression

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