The effects of chronic gamma irradiation on leaf mutations of Anubias minima were investigated. Tissue cultures of A. minima were exposed to chronic gamma radiation in a gamma room using Cobalt-60 sources at the Nuclear Technology Research Center, Faculty of Science, Kasetsart University, Bangkok, Thailand. Samples received a total dose of 0, 26.58, 41.12, 65.31, 79.81, 103.81, and 127.91 Gy at a dose rate of 0.6 Gy/h. At 60 days after irradiation, the number of surviving plantlets and the number of new shoots were counted and compared with the controls (0 Gy) to calculate the 50% lethal dose (LD50) and 50% growth reduction (GR50). The results showed that the radiation dose did not affect plant survival, but the GR50 was about 125 Gy in the M1V1 generation. After that, subcultures of new plantlets were transferred to a new medium, and the next generations were observed to note any new mutated characteristics after gamma irradiation. In the M1V9 generation, variegated leaf mutants could be selected. There were four different types of mutant leaves: Dark green leaves with light green specks, dark green leaves with white specks, light green leaves with dark green veins and specks, and white leaves with dark green veins and specks. After 3 months, the selected mutants of A. minima tissue transplanted into water tanks were healthy and had 100% survival.
Key words: Keywords: gamma irradiation, chronic irradiation, Anubias minima, leaf mutation, tissue culture
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