Influence of Gamma Irradiation on Some Physiological Characteristics and Grain Protein in Wheat (Triticum aestivum L.)

2 Abstract: Seed irradiation during pre-sowing processes is one of the most effective methods to improve the plant production, yield components and chemical composition. Therefore, an experiment was conducted using split-plot on the basis of randomized complete block design with four replications in Agricultural Research Station of Islamic Azad University of Yasouj during 2009-2010. Main plots were consisted of two wheat cultivars (Alamut and Zagros) and sub-plots were six levels of gamma irradiation including 0 (control), 25, 50, 75, 100 and 125 Gy. The results of this study showed that 1000-grain weight, grain yield, grain protein content, LAI, CGR and NAR and harvest index were affected with different levels of irradiation. The highest value of kernel weight was obtained in Zagros cultivar and 25 Gy gamma irradiation. Among the two varieties, Zagros cultivar produced more grain yield than Alamot cultivar. Grain yield increased in response to application of gamma irradiation, with the grain yield of the crop that no received gamma irradiation being 5% more than control. 25 and 50 Gy gamma irradiation produced the highest grain protein content. Increasing in gamma irradiation being more than 50 Gy decreased grain protein about 28% to 67%. The LAI and CGR varied from 4.81 to 2 and 25.6 to 12.6 (gr m day ). The highest LAI and CGR scores with average 4.81 and 25.6 were obtained 21