Investigation the reaction of three bread wheat cultivars (Triticum aestivum L.) to planting date in Ahvaz region

In order to investigate the effect of agrophysiologic traits of bread wheat cultivars to planting date, the present research was conducted on the basis of split plots experiment based on randomized complete blocks design with three replication during 2012-2013 at the research farm of Khuzestan Agriculture and Natural Resources Research Station. Three planting date mid-October, mid-November and mid-December were considered as the main plots and three spring wheat cultivars (Chamran, Chamran2 and Aflak) as sub plots. The results analysis of variance revealed that the effect of planting date, cultivar and interaction effect of treatments on all studied traits was significant at one percent probability level. The highest grain yield was allocated to mid-November planting date with chamran2 cultivar (545 gram per square meter) and the lowest one to mid-December with Aflak cultivar (273 gram per square meter). The decrease in grain yield in mid-November planting date was due to a significant decrease in spike per unit area and average seed weight. Comparison between different wheat cultivars showed that there was an inverse relationship between rate of grain filling period and duration of it, so by changing planting date from mid-October to mid-December, grain filling rate from 1.51 to 0.98 milligram per day, grain filling period from 48 to 33 days, one thousand grain weight from 41 to 28 gram and finally seed yield decreased from 467 to 299 gram per meter square. Generally, Chamran2 cultivar had the higher number of days to physiological maturity, seed yield and yield components, harvest index and grain filling rate in compared to other cultivars, so in the optimal planting date of mid-November can recommended to producers in the studied region.