Effects of Low Dose Gamma Radiation on Quality and Storability of Groundnut Seed (Arachis hypogaea L.)

Abstract

The effect of selected low gamma radiation doses on the quality and storability of groundnut seeds cv. Chinese was studied for five months under ambient storage conditions. Six radiation doses (0,1,2,3,4 and 5 Gy), two groundnut seed forms (shelled and unshelled) and eight tri-weekly intervals were combined using Completely Randomised Design with three replications. Physiological parameters (germination percentage, speed and peak value of germination; seedling, root and shoot lengths; seedling vigour index, moisture content), sanitary seed quality parameters (pathogen infectivity and insect infestation percentages) and genetic quality parameters (emergence percentage, days to emergence, days to 50% flowering, leaf and petiole colour) were observed during the storage period. Results showed significant differences between irradiated and non-irradiated seeds, and also among radiation doses for physiological parameters except moisture content. There was significant difference between the seed forms in their response to effect of radiation doses (for root and shoot lengths, and speed of germination) and storage periods (germination percentage, speed and peak of germination, and moisture content), with unshelled outperforming shelled seeds. Storage period had a negative effect on all physiological and sanitary parameters with pathogen infectivity increasing from 22 to 79.9% as storage period advanced for both seed forms and in all doses. Interaction effects between dose, form and storage period were significant (p<0.05) for all parameters except pathogen infectivity. A dose range of 2-4 Gy was found to impact stimulatory effects on germination and seedling parameters irrespective of the seed forms. However, these low doses had no influence of any sort on the sanitary and genetic quality of the seeds irrespective of the seed forms. Therefore, the irradiation of 2-4 Gy on unshelled groundnut cv. Chinese could significantly enhance quality and storability of the seeds.