Effect of Different Planting Dates on the Panicle Characteristics and Yield of Rice Cultivars in Northern Khuzestan

This study aimed at evaluating the effect of different planting dates (different ambient temperature conditions) on the characteristics of rice panicle and yield of its cultivars in Khuzestan climate in 2010. The experimental design was a split plot in a Randomized Block Design with four replications. The main factor was the planting date with three dates (May 25th, June 9th, and June 25th) and the sub factor consisted of three rice cultivars including Red Anbori (long and short), and Champa. Results showed that the highest grain yield, seed weight in each panicle, grain number, and 1000-grain weight belonged to the third planting date; the highest fertility percentage belonged to the second planting date; and the highest number of unfilled seeds in panicle and weight of unfilled 1000-grain were observed in the first planting date. With an average of 3795.4 Kg/ ha, Champa cultivar had the highest grain yield. In addition, given the correlation coefficients, grain yield had the most positive and significant correlations with 1000-grain weight (0.779*), weight of each panicle`s seeds (0.755*), and the number of filled seeds per panicle (0.403*), which indicates the high and direct impact of these characteristics on the increase of yield as well as the necessity of conducting further studies to increase the yield.