ImplicaÃÃes do nÃmero de intercruzamentos nas propriedades genÃticas de uma populaÃÃo segregante de feijoeiro / Implications of the number of intercrossings in the genetic properties of a common bean population.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

In autogamus species, like common bean na usual question about the breeding program based on hybridization, in the necessity to intercross plants of the F2 generation. The objective of this research was to verify the effect of 0, 1 and 2 intercrossings on the genetic properties of a common bean segregating population derived from multiple crossings. A involving eight parents. Part of the seeds was stored to represent the population of no intercrossing (I0). The remaining seeds were used to obtain the population of one intercrossing (I1), and the harvested seeds were split in two parts, one stored for future evaluation, and the other used to generate the population of two intercrossings (I2). All populations and two testers were assessed using a complete randomized block design with six replications. One hundred and thirty plants were taken randomly from each population to generate the S0:1 families. Those plants were selfed and the harvested seeds were mixed to generate the S0:2 families, which were assessed along with 10 testers, in a simple 20x20 square lattice design. New evaluation of the S0:3 families was set up, with sowing in July 2001, using the same design, however with three replications. In all experiments grain yield was evaluated and the genetic and phenotypic parameters were estimated. It was verified that the population average was not affected by the intercrossings, but the genetic variance presented small increment, which can be due to the linkage disequilibrium of the population or to the families x environment interaction. The increase in the genetic variance however, probably does not compensate the time and the cost spent to intercross of the F2 plants.

ASSUNTO(S)

intermating common bean populaÃÃo segregante melhoramento genÃtico vegetal segregation population feijÃo intercruzamento plant breeding melhoramento vegetal

ACESSO AO ARTIGO

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