Effect of planting date on vejetatives growth and yield of three rice cultivares in north regions of Khuzestan

This study was aimed at evaluating the effects of different planting dates (Heat stress) on the trend of Vejetative growth in addition to the yield of three rice Cultivare for one year in Shavoor regions in the north region of Khuzestan, as spilt plots in the form of fully random blocks in three repetitions. Main factor was the date of planting at three levels (26 May, 10 Jun, 26 Jun) and the second factor was in three levels including of Red Anbori varieties (long and short grains), and Champa. Results Analysis of variance indicated that there is a significant difference between different dates of planting and all properties; but to other of stem dry weight and fertility percentage, remnant characteristics there is not any significant difference in the interaction of both factors. Also maximum and minimum amount stem dry weight and height plant inverse grean yield, 1000-grain, fertility percentage, harvest index and leaf dry weight were related to the 1 and 3 dates. trend of all characteristics on 26 May, which had the maximum thermal stress at the reproductive stage, they reached the maximum growth in a shorter period of time. Among the Cultivares, Champa had the highest yield with an average of 3795/4 kg/ha. with attention Correlation coefficients maximum affirmative and significant grean yield was on the leaf dry weight (0.441*). Based on the results, it can be hoped that the yield of grain resulted from the increase of the growth and net photosynthesis in rice would be increased by focusing the breeding purposes on increasing the leaf weight.