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The Effect of Gamma Radiation on Some Physiological Characters of Bread Wheat {Triticum aestivum L.)

In this study seeds of " Alvand" cultivar of bread wheat were exposed to different doses (300, 600 and 900 rad) of cobalt 60 gamma radiation for 1-10 consecutive days. At the end of radiation periods, 30 groups of irradiated seeds and one group of control (without irradiation) seeds were obtained. Ten seeds from each group were let to germinate and grow in pots to measure yield in natural environment. Results showed that seed having irradiated with 300 rad of gamma rays produced plants with longer stems, as compared with those of control seeds. The rate of stem length increase at 7th to 9th days irradiations was very significant. Na uptake of seeds in 3rd day of irradiation with 300 rad also increased significantly. Increase in the amount of K uptake was significant from 3rd to 9th days irradiation with 300 rad in comparison with those of control seed. This was greater at 3rd to 9th days than when seeds irradiated with 600 to 900 rads. The amount of increase in seed weight was maximum at 8th to 9th days of seed exposure to gamma radiation. It seems that radiation of seeds with 300 rad at 3rd day of irradiation resulted in higher K and Na uptake, but their radiation with higher doses of gamma rays decreases the uptake of these two elements. Results also indicated that irradiation of seeds with 900 rads, at least for 8 days or more, increase seed weight appreciably. It may be concluded that irradiation of seeds with 300 rads by exposing the seed to gamma radiation for three days increase K and Na uptake, but their uptake of these two elements would decrease when higher doses were used.