Effect of Proton Beam Irradiation on M1 Seeds and Seedling Growth in Rice

This study was carried out to evaluate effect of proton beam irradiation on M1 seed germination and seedling growth. For dosage effect, mature and healthy Supersami2 seeds were irradiated with 0, 204, 395, 502, and 700Gy. The traits for germination were not affected by dosage effect of proton beam irradiation. Germination rate evaluated at 7 days after imbibition ranged from 93.3% to 98.7%; germination vigor ranged from 59.3% to 68.7% where in the dose of 700Gy showed the lowest value of 59.3%. The average days of germination ranged from 1.36 to 1.48. The seedling growth was affected by the dosage. Withered rate (withered plants after germination) was increased as the dose increased. The withered rate of 53.9% was detected in 395Gy and no plant survived in 700Gy. In the ~400Gy treatment, the sensitivity of the traits of germination among Dianxi4, Jeogjinju, MS11(Maligaya Special 11), and Superjami2 was not different while the withered rate was different: 9.7% in MS11, 32.1% in Dianxi4, 53.9% in Superjami2, and 59.7% in Jeogjinju. Based on the germination rate and withered rate, it can be suggested that 350Gy to 450Gy is a starting point for applying proton beam irradiation to rice seed for mutation breeding.