MUTATION FREQUENCY AND CHLOROPHYLL MUTATIONS IN PARENTS AND HYBRID OF COWPEA FOLLOWING GAMMA IRRADIAnON

Abstract

Gamma rays altering the mutation frequency and chlorophyll mutations in cowpea parents and their FI hybrid at different doses were studied. The mutation frequency increased gradually up to moderate doses of gamma rays and the highest frequency rate was found in the variety Co 4 on MI plant basis. The frequency was dose dependent. The mutant viridis was more frequent in the total spectrum, while chlorina and xantha were in equal proportions, followed by albina and alba-viridis. The mutagenic effectiveness was higher with high doses in Co 4, and with moderate doses in C 152 as well as their hybrid. However, efficiency was maximum when calculated on lethality basis, followed by injury and sterility basis. In cowpea, 50 krad of gamma rays was found to be the most efficient dose.