Radio-sensitivity test of five cowpea genotypes

The productivity of cowpea is much less, when compared to other pulse crops because new varieties do not satisfy the consumer needs and the expected yield of farmers. Mutagenesis is one of the effective methods of crop improvement. To effectively administer an acute dose for mass irradiation, differential sensitivity of cowpea genotypes to gamma rays is required. This is a prerequisite for further improvement using mutagenesis. The objective of this study is to determine LD50 and RD50 of various genotypes to gamma rays (differential sensitivity to gamma rays). Five cowpea genotypes (Hansadua, WC-36, ACC122WxWC- lO, IT97K-819 and WC-10) were irradiated with gamma rays from 60Co source at Ghana Atomic Energy Commission (GAEC) at thirteen doses of from 0 - 1,200 Gy at 100 Gy intervals. Data were collected on germination, plant height, whole seedling weight, root weight, root length and shoot weight. The data were analyzed using Genstat version-12 to determine the LD50, RD50 and ANOVA. The lowest LD50 value was 531 Gy for Hansadua (most sensitive to gamma rays) and the highest of 903 Gy for ACC122WxWC-10 (most tolerant to gamma rays). The RD50 showed a positive relationship between the seedling height and gamma rays administered. It was observed that the response of cowpea genotypes to gamma rays differ.