Effect of X-Ray Irradiation on the Growth and Yield Parameters of Four Cowpea (Vigna Unguiculata (L.) Walp) Genotypes

Abstract

Induced mutagenesis has been used as a tool in improving the
agronomic traits of crops. The effects of different x-ray irradiation
doses on vegetative and yield parameters of four cowpea (Vigna
unguiculata (L.) Walp) genotypes (Black eye, Light brown eye, Dark
brown eye and Ife brown) were evaluated. The seeds were subjected to
various x-ray doses (0, 5, 10, 15 and 20 mGy). The experiment was set
up in a 4×5 factorial experiment in randomized complete block design
(RCBD) with three replicates. The result revealed that x-ray irradiation
dose (10 mGy and 15 mGy) induced obvious variability in all the
vegetative parameters (Days to 50 % emergence, plant height, number
of leaves, leaf area, stem girth and number of branches). Yield
parameters such as days to 50 % flowering, pod length, 100 seed
weight, seed yield per pod (g) and grain yield per hectare (t/ha) were
significantly increased to maximum by the different X-ray doses when
compared to the control plants. Among the four varieties and
treatments, light brown eye at 15 mGy performed better in yield when
compared with the other varieties studied. Contrastingly, the high
mutagenic dose of 20 mGy substantially decreased all the vegetative
and parameters as compared to the control. Therefore, the overall
result reveals that low x-ray irradiation doses of 10 mGy and 15 mGy
could induce variability and enhance vegetative growth and yield of
cowpea. Thus, it is recommended that x-ray be employed in the
breeding program of cowpea.