SeleÃÃo recorrente fenotÃpica para florescimento precoce de feijoeiro tipo carioca / Phenotypic recurrent selection for early flowering of âcariocaâ common bean

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The present study was conducted to evaluate the efficacy of phenotypic recurrent selection for the number of days to flowering in common bean and to determine the effect of the correlated response to selection for other relevant traits. The base population was developed in a partial diallel crosses of five early lines (AN 512666, PVBZ 1875, âPreto 60 diasâ, âPitocoâ, âQuarentenoâ) and ten with a normal cycle (âBRS TalismÃâ, âBRSMG Majestosoâ, LH-11, OP-S-16, LP-98-76, MA-I, âEtÃâ, âFT Bonitoâ, âPÃrolaâ and âAporÃâ), resulting in 49 F1 hybrids which were evaluated for early flowering. The 11 hybrid populations that presented the lowest number of days to flowering were selected and mixed to establish the S0 base population (cycle 0). The S0 seeds were sown on an experimental field. At flowering, the earliest plants were selected and intercrossed to establish cycle I. For cycle II, the hybrid seeds of cycle I were sown and the plants that flowered first intercrossed. The same procedure was repeated to establish cycles III through V. In the S1 generation of each cycle, 53 plants were selected, amounting to 318 S1:2 progenies and six controls which were evaluated in February 2006. The traits number of days to flowering, number of days to maturation, grain yield (g/plot), severity of angular leaf spot (scores from 1 to 9) and grain type (scores from 1 to 5) were assessed. With the underlying mean data of the simultaneous evaluation of the S1:2 progenies of the selection cycles, the genetic selection gain for the number of days to flowering was estimated. Per year, the selection gain was 2.2%, indicating that phenotypic recurrent selection effectively reduced the number of days to flowering. The estimates of the genetic and phenotypic parameters of the different selection cycles allow the inference that continuous gains could be obtained with recurrent selection. The response to selection for the number of days to flowering was not correlated with the other evaluated traits, indicating the possibility of selecting progenies that associate early flowering with the phenotypic expression of other traits of the breederâs interest.

ASSUNTO(S)

feijÃo seleÃÃo recorrente florescimento precoce recurrent selection early flowering bean melhoramento vegetal

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