RADIOSENSITIVITY TEST OF TOMATO (SOLANUM LYCOPERSICUM) TO GAMMA IRRADIATION
This study was conducted to investigate the 50% lethal dose, (LD50) and the effects of gamma ray radiation on seed germination, plant height, survival percentage and dry weight of seedlings derived from irradiated seeds of tomato (Solanum lycopersicum). Tomato seeds were irradiated at dose 200, 400, 600, 800 and 1000 Gy with gamma rays of Cesium-137 (Cs-137) using Gamma Cell at Malaysian Nuclear Agency. The irradiated seeds including the control were sown in the planting tray with sand and topsoil at 3:1 ratio in the shade house. Water was applied manually twice a day to maintain the soil moisture. The Randomized Complete Design with three replications was used in this study. The 50% lethal dose (LD50) of tomato was determined. The results showed that seed germination percentage, survival percentage, plant height and plant dry weight of tomato decreased with the increasing of gamma ray dose. In this study, gamma ray dose above 600 Gy had a lethal effect on these variables due to the injury that may have caused to the seeds of tomato. This resulted in poor plant growth and development or even fatality. The low gamma irradiation doses enhanced some of the growth parameters, however high doses severely affected these traits. From this study, LD50 of tomato survival rate was estimated at 340 Gy in this study.