The Yield of M7 Mentik Wangi Rice Irradiated With Several Doses of Gamma Rays Under Drought Stress

Abstract

The possible risk of yield losses due to drought stress could threaten rice production and national food security. One way to deal with drought limitations is by developing drought- tolerant varieties using gamma-ray irradiation. This research aimed to get the optimal dose of gamma-ray radiation to create an M7 generation of Mentik Wangi variety that is drought tolerant. Field experiments were conducted from December 2020 to March 2021 at the Screen House of the Faculty of Agriculture, Universitas Sebelas Maret, Surakarta, the Laboratory of Soil Physics, and the Laboratory of Plant Production Management, Faculty of Agriculture, Universitas Gadjah Mada. This study has carried out using a Randomized Complete Block Design with two factors. The first factor is gamma-ray irradiation dose (0gy. 100gy, 200gy, 300gy), and the second factor is drought stress treatment (without drought stress and drought stress in the flowering stage) with three replications. The results showed no interaction between gamma-ray irradiation dose and drought stress on all observed variables except plant dry matter. Drought stress in the flowering stage increased the percentage of unfilled grain, reducing the harvest index and grain weight significantly by 40.9%. Gamma-ray irradiation in a range of 100 to 300 gy did not affect panicle numbers and length, also the percentage of unfilled grain, but reduced the number of grains per panicle, thereby reducing the harvest index and grain weight 45.0% compared to those without irradiation.