The aim of this study was to investigate the genetic control of traits related to plant architecture in cowpea: length and number of nodes on main stem, growth habit, from the crossings TE96-282-22G x TVX-5058-09C and TE96-282-22G x IT81D-1332. The experiment was conducted at Embrapa Mid-North, Teresina, PI, Brazil, in 2003. Experiments were carried out under randomized block design with four replications. Genetic components of mean and variance and heritability for the traits length and number of nodes on main stem were estimated. Growth habit was based on the frequencies of the phenotypes observed. In both crosses, the additive-dominant genetic model was sufficient to explain the phenotypic variation observed for length and number of nodes on main stem; additive and dominance effects are important in controlling the length and number of nodes on main stem, but the additive variance is prevalent as a component of genetic variance. Length and number of nodes on main stem presents oligogenic control associated with a high expression of trait. Growth habit has monogenic control, with dominance for the indeterminate type.
Vigna unguiculata; main stem length; number of nodes in main stem; growth habit; genic effect; heritability
