Heritability and gene action of cowpea (Vigna unguiculata) resistant to pod stucking bug Clavigmlln tomentosicollis

Abstract

An experiment was conducted during 2003 and 2004 to estimate the gene action and heritability in cowpea (Vigna unguiculata (L.) Walp) resistance to Clavigralla ton~erztosicollis( Stal.). Five cultivars ('TVu745', 'TVu2562', 'IT87D- 979-1 ', 'TVu10224') 'TVu9.525' and 2 susceptible varieties ('13843-2246', 'IT84E-124') were used. Crosses were made between the resistant and susceptible cultivarsto obtain F,, F,, F,,BCP,,and BCP, generations. Generation mean analysis was done on pod evaluation index which measures the level of resistance o;susceptibility of the plants using their podload and pod damage. Majority of the crosses exhibited significant additive and dominance gene effects in the joint scaling test on pod evaluation index. Broad sense heritability estimates for pod evaluation index were generally higher than the narrow sense estimates. There was no correlation between pod evaluation index and yield components like the number of seedsfpod, 100-seed weight and pod wall thickness suggesting that these yield parameters may not have contributed significantly to the resistance of cowpea to this pest.