Relação entre caracteres determinantes do ciclo e porte do feijão-caupi em níveis variados de homozigose

Abstract

Currently, cowpea breeding programs seek to obtain cultivars that have not only high productivity, but also erect and early cycle. This is because besides facilitating manual and mechanical harvesting possible that the plant remains less time field reducing negative consequences of biotic and abiotic effects. Thus, the use of tools to facilitate the selection process is essential for the work of the breeder. In this sense, the correlation between characters is a good alternative for this purpose, as well as enabling identify related characters that are easier to measure, makes it possible for early selection. It aimed to compare the relationship between determinants of the cycle characteristics and size in cowpea progenies with different levels of homozygosity. For this, we used 10 cowpea progenies previously selected and extracted from a complete diallel conducted among parents CE-542, CE-796, CE-945, CE-954, F4RC1 e MNC03-737E-5-10. These ten progenies were selected generation F3, getting to the end of the seed cycle F3:4. At the end of the first evaluation, the seeds were obtained F3:5, in the absence of selection were again evaluated in the presence of these witnesses. Both tests were carried out in the municipality of Marco-CE, in irrigated perimeter region of the Acaraú, in a randomized block design with three replications. The agronomic traits were: number of days to flowering (NDF), number of days to maturity (NDM), plant height (ALT), pod length (CPV), number of seeds per pod (NGV), mass hundredfold (M100G) and total mass of grain (MTOTAL). With the means of each character measured the correlations were obtained between them for two generations and then the track diagram with MTOTAL as the main variable. It was observed that the associations between CPV and M100G and between NGV and MTOTAL showed positive correlations and can be used in breeding programs in both homozygous levels studied. In path analysis it was observed that the generation most suitable for the use of indirect selection would be F3:5 and the ALT character was one that stood out. This indicates that indirect selection on the basis that character that homozygosity level would result in significant genetic gains in MTOTAL.