Genetic parameters and association between agronomic traits in special-grain common bean (Phaseolus vulgaris L.) genotypes.

Estimates of genetic parameters allow to determine the genetic variability present in a population, constituting one of the initial steps in a breeding program. The objectives of this study were to estimate genetic parameters and identify agronomic traits directly and indirectly correlated with grain yield (GY), as well as to estimate their direct and indirect effects on the yield of special-grain common bean genotypes. The experiment was carried out in the 2016/2017 season, in a complete blocks design, with three repetitions. The evaluated traits were days to flowering, days to maturity, first pod height, plant height, number of pods per plant, number of grains per pod, mass of hundred grains, and grain yield. Data were subjected to analysis of variance, and genetic parameters were estimated followed by phenotypic and genotypic correlations. Phenotypic and genotypic correlations were split into direct and indirect effects by path analysis. The studied population seemed promising for breeding purposes considering most traits. Correlation and path analyses indicated that there was a positive direct effect of days to maturity on grain yield. The traits days to maturity and mass of hundred grains can be used in indirect selection aiming at higher grain yield. Path analysis also revealed that the indirect effects of number of pods per plant and number of grains per pod should be taken into consideration in the genetic breeding of the common bean for the increased grain yield. [ABSTRACT FROM AUTHOR]