Induction of Genetic Variability in Cowpea Variety Videza for Extra Earliness and High Seed Yield using Gamma Irradiation Mutagenesis

Abstract

Background: Cowpea yields are very low in the West African region due to the prevalence of drought periods. This work, therefore, aimed at developing cowpea genotypes that combine early maturity with high seed yield, through gamma irradiation mutagenesis. Methods: A farmer preferred cowpea variety Videza was improved via gamma mutagenesis. A determined lethal dose 50% (LD50) of 240 Gy was used to irradiate 2000 seeds of Videza by applying a Cobalt 60 source. Selected M1 generation plants exhibiting early maturity and high seed yield were advanced to M2 and further to M3 using Videza as parental control. Result: Compared to the control Videza, the number of days to 90% maturity significantly decreased in putative mutants in the M2 (from 71 days in the control to between 50 and 66 days in mutants) and further decreased in the M3 where mutants matured 10-22 days earlier than the control. Significant increment in 100-seed weight per plant occurred in the M3 mutants. In the M3, 100-seed weight increased from 15.28 g in Videza to 21.71 g, the highest in mutants. Twelve putative mutants were identified that combine early maturity with higher seed yield than the control.