Potencial genético de progênies de feijão-caupi para a obtenção de genótipos de porte ereto e ciclo precoce

Abstract

In addition to high yield, the cowpea breeding programs have been based on the development of cultivars that erect associate and early cycle. This is because in addition to minimizing the risk of losses because the plants spend less time in the field, makes it easy to harvest, either manually or mechanically. For this purpose, are generally employed methods involving hybridization to give segregating populations, these, in turn, are driven by several generations of inbreeding. This process is costly and time consuming, and early identification of populations with potential for extraction lines, can greatly reduce the costs of a breeding program. For this, the methodology m + a, which estimates the concentration of favorable alleles in two consecutive generations, is a good indicator. Subsequently, it should identify the best genotypes within those potential people to compose the final testing lines, conditioning to obtain cultivars that meet the objectives of breeding programs. Thus, the aim of the first study (Chapter 1): (i) estimate the genotypic values (BLUPs) to agronomic important traits, and (ii) to investigate the potential use of the methodology m + a for the early selection of lines. In the second study (Chapter 2), aimed to verify the existence of genetic variability in the population and identify promising lines to compose the final rehearsals. To estimate the genetic potential of populations for early extraction lines were evaluated generations F3:4 and F3:5 ten progenies. These were evaluated in a randomized block design with three replications. To identify the best individuals to compose EFL, we used seeds from 119 genotypes originated ten progenies F3:4, and two witnesses, Sempre Verde and BRS Tumucumaque. It was used for this design in a 11 x 11 square lattice with two replications. The trials of the two studies were conducted in Marco-CE council and evaluated characters: number of days to flowering (NDF); number of days to maturity (NDM); plant height (ALT); pod length (CPV); number of seeds per pod (NGV); weight of 100 grains (M100G), and total mass (MTOT). We identified high heritability values in terms of average and accuracy for most of the characters, as well as low coefficients of variation, except for MTOT character. Positive and negative genotypic values of the progenies showed the potential to increase the expression of those characters related to productivity and reduce the expression of those associated with size and precocity. The estimate m + a more expressive for ALT was presented by the progeny obtained from the crossing of the EC-796 and MNC03-737E-5-10. And for NDF and NDM the progeny obtained from the crossing of the EC-796 and EC-954. The estimate the m + a was viable for identification of populations with potential for extraction lines in cowpea culture. In the second study, the genotypes 5, 7, 14, 15, 25, 27, 31, 42, 47, 57, 85 and 113 were those which showed greatest genetic potential for composing EFL.