Assessment of the effects of gamma irradiation on the growth and yield of Digitaria exilis [Haller]

Abstract

Objective: Mutagenesis has been used in several crop improvement programmes but only on a very limited scale for Digitaria improvement and in order to further strengthen the existing conventional improvement methods, we report enrichment of Digitaria exilis variability by exploiting the effects of gamma radiation of different doses on yield and growth of the crop. Methodology and Results: Digitaria exilis seeds were exposed to gamma irradiation (20Gy, 40Gy, 80Gy, and 100Gy) from 60 Co source and irradiated seeds were sown for evaluation. The effects of the irradiation doses were studied on germination, seedling characters, growth, and yield parameters at maturity. Days to emergence and percentage germination were enhanced at low irradiation doses with 80Gy producing optimally. Plant height, tillering and number of leaves were significantly affected by gamma irradiation and analysis of obtained data showed irradiation significantly affects percentage seed-set, number of spikes/tiller and number of spikelets/spike. Also, early maturity was achieved among irradiated plants and 100-grain weight was highest at 80Gy. Conclusion: Plant from 80Gy irradiation dose performed optimally for all the characters evaluated in this study. Hence, 80Gy or slightly low dosage form of gamma irradiation using cobalt (60) could be utilised to increase variability and yield in Digitaria exilis. The new or modified traits so created could be screened for the possibility of isolating and selection of mutants that are promising for further improvement breeding programmes.