Evaluating the Effect of Different Planting Dates on Panicle Growth Trend and Performance of Rice Varieties in Khuzestan Region, Iran

This study was aimed at evaluating the effect of different planting dates on the panicle growth trend (length, weight, and branches of panicle) and the performance of rice varieties in the north of Khuzestan province with east latitude of 48 ^o: 28◌َ and north longitude of 31 ^o: 50◌َ executed as spilt plots in the form of randomized complete blocks with three repetitions. Main factor was the date of planting at three levels (June 5^th, June 20^th, and July 5^th) and the secondary factor includes the varieties of red Anbori (tall and short grains), and Champa. Results indicated that the maximum performance of the seed, floret in panicle, and weight belonged to the date of July 5^th and the maximum length of panicle and branches, without significant difference, be longed to the second date of planting. evaluating the growth trend, maximum increase (rate of growth) of the dry weight and number of floret was due to the more-appropriate heat and the reduction of sterility as well as a more demand for non-structural carbohydrates (unlike the planting date of June 5^th) in the planting date of July 5^th, but the length of panicle had its most growth rate in the first two planting dates, while the number of branches was not affected by the date of planting. Among the varieties, Champa , with an average of 3795/4 kg/ha , had the maximum efficiency . Based on the results of this study, by focusing on the modifying objectives to increase the dry weight of the panicle, because of its positive and high correlation (0/759**), increase of the rice seed`s efficiency can be hopefully predicted.