The effect of gamma irradiation on potato microtuber production in vitro

The effects of low doses of gamma irradiation and potato (Solanum tuberosum L.) cultivar on the production of microtubers in vitro were investigated. Nodal segments from virus free explants of three potato cultivars (cv.) wer e placed on tuberization inducing medium and irradiated with 4 doses of gam ma radiation (2.5, 5, 10, 15 Gy). Cv. Diamant produced the highest number o f microtubers followed by Draga and Spunta. Irradiation of the explants wit h 2.5 Gy of gamma radiation led to a significant increase in the number of microtubers (38% increase over the control). Average weight of microtubers was not significantly influenced by low doses of gamma irradiation. Draga m icrotubers were the largest followed by Diamant and Spunta. Microtubers res embled mature tubers in shape (Spunta was oval and Draga and Diamant were s pherical). Size of microtubers was crucial for sprouting in vivo. It is sug gested that only microtubers larger than 5 mm in diameter (250 mg) be used to produce minitubers in vivo. Since 2.5 Gy is a low irradiation dose, it c an be used to enhance tuberization in vitro without fear of genetic changes in the used cultivars.