This investigation was carried out to determine the effects of gamma radiation on germination and physiological characteristics of wheat seedlings. Two wheat genotypes (Roshan and T-65-58-8) were irradiated with 100, 200, 300 and 400 Gy. The results showed that MGT (Mean Germination Time), root and shoot length, and seedling dry weight decreased with increasing radiation doses but final germination percentage was not significantly affected by radiation doses. Biochemical differences based on proline content revealed that seedling irradiated at 100 Gy contained highest amount of proline (1.71 mg/g FW), whereas only 0.92 mg/g FW of proline was detected in nonirradiated seedlings. The highest amount of total chlorophyll content was obtained in seedlings irradiated at 100 Gy. Furthermore, the concentration of chlorophyll a was higher than chlorophyll b in both irradiated and non-irradiated seedlings. Chlorophyll and proline contents, and root and shoot dry weights in cv. Roshan were higher than those in T-65-58-8 mutant. These results show that the up-regulation of some physiological characteristics and seedling growth of wheat following gamma radiation treatment may be used for aboitic control such as drought and salt stress.

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