Evaluation of Wheat Genotypes Response to Chilling Stress at Heading Stage Using Physiological Indices, Yield and Yield Components

Temperature reduction since late December until late February is a dominate climate phenomena in Khuzestan which caused plant damage and subsequently yield reduction. In order to study the effect of chilling stress at heading stage on yield, yield component and some physiological traits of wheat genotypes, this research was carried-out with five genotypes (Chamran, Vee/Nac, Star, Kharkheh cv. and line M-83-17) and four environmental temperatures(non-stress, and+3,0 and -3°C) under greenhouse condition, in factorial experiment using CRD with three replications in Khuzestan Natural Resources and Agricultural Research Center in 2013. Date of physiological maturity, plant height and spike length, yield components including spikelet/spike, grain no./spike, 1000 grain weight and grain weight in main spike and Fo, Fm, andFv/Fm indices were evaluated. Results showed that the effect of chilling stress was significant for days from germination to physiological maturity, grain no. per spike, grain weight in main spike and Fv/Fm traits. The highest grain weight in main spike under non-stress and -3°C chilling stress was belonged to line M-83-17 and Chamran cultivar, respectively and under zero and 3°C chilling stress were obtained from Chamran cv. and Vee/Nac, respectively. The highest difference before and after chilling in Fv/Fm index was belonged to zero chilling stress. Differences in traits which were studied in this research indicated genetic variation in genotype response to chilling stress