Effect of Planting Date on Yield of some Rice Cultivars in Khorramabad Condition

In order to determine the best cultivar and planting date of rice in Khorramabad area, this study was conducted in RCBD as split – plot with four replications in 2003 and 2004. Main plots were four planting dates (April 14, April 23, May 3 and May 13), and three cultivars (Domsiah , Binam and Hashemi) were used as subplots. Results of analysis of variance showed that the effects of planting date and cultivar and planting date × cultivar interaction on seed yield was significant. Domsiah cultivar with 2985.2 kgha-1 in second planting date (April 23) had more seed yield than others. Early and delayed planting dates decreased yield, because of short vegetative period in early planting and high temperature during flowering period in delayed planting date. Planting of Domsiah cultivar in second planting date (April 23) can be recommended for Khorramabad condition, because of its long growing period and phenological stages in optimum temperature.