Agro-morphological response of rice (Oryza sativa L.) (cv MR 284) to chronic gamma irradiation

Abstract

An experiment to study the effect of cobalt 60 gamma irradiation on agronomic traits of Malaysian rice variety, MR284, was performed by using randomized complete block design (RCBD) with three replications in Gamma Green House (GGH) located at Malaysia Nuclear Agency. The GGH facility can produce a low dose rate of chronic gamma-ray which causes less damage to the plant cell and eliminate undesirable traits as well as produce wide mutation spectrum. Seedlings in pots at the age of 14 days were exposed to gamma rayS in GGH at different dose rate from 0.03 Gy/hour to 0.66 Gy/hour for 77 days (flowering stage). Data on survival rate and growth performance such as plant height and tiller number were recorded every 7th day. The result showed that, chronically irradiated MR284 plant exhibited various significant responses of agronomic characteristic against different doses of chronic gamma irradiation. Based on the survival curve, growth reduction (GD50) for MR284 was recoded at 318.63 Gy based on filled grain per plant trait. At cumulative doses of 68.87 Gy and 167.25 Gy (0.07 and 0.17 Gy/hour, respectively), the rice seedlings demonstrated the highest plant height with maximum tillering and highest number of filled grains. Those rates are stimulating to the growth and development of the plants. This study helps explicate the dose-response on local rice varieties through chronic radiation in a Gamma Green House facility in Malaysia.