Radiosensitivity to gamma rays (60Co) in shoot tips of henequen

Abstract

The current research was carried out with the objective of evaluating the radiosensitivity of shoot tips from henequen (Agave fourcroydes) to gamma radiations 60Co and to determine the optimum dose of radiation for breeding program in the cultivar Sac Ki. Shoot tips of 20 days of in vitro culture were selected and irradiated with five doses between 10, 20, 30, 40 and 50 Gy using a 60Co source. Evaluations were aimed to determine increasing of fresh weight of explants in relation to the control (no irradiated material), number of dead explants and average number of axillary shoots per explants. Percentage of mortality was bigger when irradiation dose was increased. Irradiation 20 dose of Gy was GR50, increasing fresh weight of explants in a 49.6% in relation to control. LD50 was 30 Gy and a 50% of irradiated explants died. When increasing irradiation dose the number of explants decreased, though starting of sprouting took place after 90 for both, irradiated and non irradiated explants, suggesting that this parameter was not radiostimulated nor radioinhibited. Results enable to suggest the application of 20 Gy in studies aimed to create genetic variability in breeding programs by mutation induction. Key words: Agave fourcroydes, plant breeding, tissue culture