بررسی اثر تقسیط کود نیتروژن بر عملکرد کمی و کیفیت دانه ارقام برنج (هاشمی و بهار 1) در گیلان

In order to investigation of nitrogen fertilizer split application effect on quantity yield and grain quality of rice varieties, an experiment was carried out based on RCBD design as split plot experiment in three replications in Langroud in 2006. Mainand sub factor were variety (Hashemi and Bahar 1) and five nitrogen fertilizer split application (split of 150 kg.ha^-1 N at transplanting, stemming, heading and flowering stages). Quantity traits (yield and its components, straw yield, harvest index, plant height, main and sub panicle length) and three cooking quality index include: grain amylose content, gel consistence and gel temperature were measured. Results showed that the effect of split application was significant on grain yield, stuble yield, 1000 grains weight and plant height. N1 split (50% in transplanting and 50% in stemming) was the best treatment with 6619 Kg.h^-1 mean yield. This split in Hashemi has more harvest index and amylose content (45.75% and 22.21%, respectively). Bahar 1 with more mean grain yield (6977 Kg.h^-1) and harvest index (49.87%) than Hashemi (3933 Kg.h^-1 and 40.35%) have significant difference. Also Bahar 1 has significant difference with Hashemi in mean of the number of grain in main and sub panicul (192.08 and 124.83, repectively). Hashemi and Bahar 1 were set in moderate and low amylose content groups, with 21.45% and 19.21%, respectively. The interaction effect between split and variety was significant on straw yield, harvest index, 1000 grains yield, percent of unfilled grain and plant height.