Potencial reprodutivo da semente de feijão em diferentes fases de desenvolvimento / Reproductive potential of common bean seed at distinct developmental stages

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The precise stage for common bean harvest as a function of the best germination and vigor conditions of the seed has been the object of many studies. Such knowledge besides promoting a more efficient seed production, and as such, resulting in general gains for the farmers, mainly those that produce their proper seeds, may suggest the correct moment for harvesting the seeds when considering more rapid generation advance in breeding programs. The present study aimed to determine the adequate moment for harvesting common bean seeds that would result in a higher efficiency in the production of a new seed generation, as well as the earlier developmental stage of the seed, starting at 30 days after flowering, that would permit the regeneration of a new common bean plant, in this case, accelerating the generation advance process. The experiments were conducted under greenhouse and laboratory conditions at the Estação Experimental de Terras Baixas of Embrapa Clima Temperado, located in Capão do Leão, Rio Grande do Sul State, Brazil, in 2005. Experimental design was randomized complete blocks with split-split-plots, in two replications. Treatments were the combination of the factors cultivar (Chocolate, Guabiju, TPS Nobre and Carioca), seed developmental stage (30, 35, 40, 45 and 50 days after flowering), seed drying method ( slow drying, atroom- conditions drying, and no-drying) and substrate (germination paper tissue and soil). From flower opening on, flowers have been individually identified by means of colored wool threads, daily, in order to make it possible the identification of seeds at the same stage of development at harvest. At each seed developmental stage, 23 pods per replication of each cultivar were collected. From these, 18 were kept for experimental determination and 5 for seed moisture content evaluation. Physiological quality of the seeds was determined through germination percentage and vigor index. Variables under study were evaluated at two experimental phases: in the first, the number of seeds per pod (NSP) and in the second the number of germinated seeds per pod (NGSP) and the number of plants produced by pod (NPPP). Statistical 9 analyses were analysis of variation and analysis of covariation, followed by polynomial regression analysis and multiple comparison tests, for treatment variation decomposition. Results have shown that the minimum period for harvest, in terms of a high efficiency in seed and grain production, is 45 days after flowering. The best seed developmental stage for generation advance varied according to cultivar. From 45 to 50 days after flowering it was detected a quick decrease in seed moisture content. Drying at-room-conditions and no-drying were the most efficient drying methods where as soil was the superior substrate. Seeds collected 30 days after flowering were able to produce a new generation.

ASSUNTO(S)

phaseolus vulgaris agronomia avanço de gerações vigor generation advance germinação vigor phaseolus vulgaris reproductive potential capacidade reprodutiva germination

ACESSO AO ARTIGO

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