Determining the genetic variability and correlations between traits of interest for selection in a population is one of the stages in a breeding program. The objectives of this study was to evaluate the potential for genetic improvement of a population composed of 19 cowpea genotypes of erect and semi-erect growth habits, involving commercial varieties and advanced lines. Genetic and phenotypic parameters and correlations between phenological and morphological traits of the population were estimated. The trial was carried out at the experimental field at the Universidade Estadual de Mato Grosso do Sul, in Aquidauana, in the dry season of the crop year 2007/2008. The following traits were evaluated: days to flowering (DF), days to maturity (DM), mass of 100 beans (MHB), length of pod (LP), mass of pods (MP), number of seeds per pod (NS) and dry bean yield (DBY). There was a significant effect of genotypes on all traits, indicating the existence of variability. The highest estimate of the genetic variation coefficient was obtained for DBY which also had the highest coefficient b (2.05), indicating favorable condition for the selection of this trait. Among the other traits only DM had coefficient b above one. There were positive and significant genetic correlations between all the traits and DBY; however, the highest were DF, MP and NS. These findings showed that this population has the potential for genetic improvement and the increase in bean yield can be obtained especially for the later genotypes.
Vigna unguiculata (L.) Walp; phenotypic parameters; genetic variability
