Investigating the effects of different cultivation dates on the yield and some agronomic properties of rice cultivars in the North of Khuzestan

The present study was carried out in order to examine the effects of different cultivation dates on the properties of panicle and the yield of rice cultivars using a split plot design in the form of a randomized complete block basis with three replications in the crop year of 2010-11. The main factor was cultivation date at three stages (26 May, 10 and 26 July) and the sub-factors were Red Anbouri (long and short) and Champa. The results of the variance analysis indicated that the effect of cultivation date and the cultivar on the yield of the rough rice was significant at a level of 1%. First cultivation date resulted in maximum total dry material with an average of 13810 Kg.ha-1, maximum flag leaf width with an average of 1.14 cm, height with an average of 120.89 cm, and number of plants with an average of 504 plants per square meter. The second cultivation date caused the maximum flag leaf length with an average of 33 cm, day up to 50% of flowering with an average of 108 days. The third cultivation date led to the maximum yield of rough rice with an average of 4269.33 Kg.ha-1, harvest index with an average of 40.01%, the number of florets and seeds with averages of respectively 187.67 and 161.44 per cluster, the dry weight of flag leaf with an average of 0.14 gr and day until full maturity with an average of 144 days. As a result, the third cultivation date due to avoid susceptible panicle emergence to heat stress, is the best time of rice cultivation to achieve the highest agrain yield in Kuhzestan.