GAMMA RADIOSENSITIVITY STUDIES ON ZINNIA ELEGANS VAR DREAMLAND

The success of induced mutagenesis technique using gamma rays in any crop or ornamental plants lies in the determination of optimum dose (LD50). The study aims to determine the optimum dose of gamma rays in Zinnia elegans var Dreamland and the effect of different doses of gamma radiation on the germination and survival rate, plant height and root length. The seeds were treated with 10Gy, 20Gy, 50Gy, 75Gy, 100Gy, 125Gy, 300Gy, 400Gy and 500Gy at Bhabha Atomic Research Centre, Mumbai using 60CO source. The results revealed that there was significant decline in the germination rate after 50Gy gamma radiation dose and no significant variation in the survival rate until 300Gy as compared to the control. The LD50 for % germination and %survival was found to be 155.98 and 250.78. The higher gamma ray doses significantly decreased the plant height and root length. 40% reduction in shoot length and root length was found to be 250 to 260 and 210 to 220.