Response of Some Bread and Durum Wheat Genotypes to Different Levels of Nitrogen in South West of Iran

In order to identify the effects of different levels of nitrogen fertilizer on seed yield and seed growth indices of some bread and durum wheat genotypes, a field experiment was conducted in 2013-2014 in Khuzestan Agricultural and Natural Resource Research Center. The experiment was designed as a split plot with three replications. Nitrogen application rates (50, 100 and 150 kg N.ha-1) were assigned in the main plots and the sub plots consisted of six wheat genotypes (Bread; Verinak, Star, Chamran and Durum; Karkheh, D-84-5, D-83-8). Results indicated that seed yield, seed protein percentage, seed effective filling rate, remobilization of dry matter and the current photosynthesis, 1000 seed weight and seed effective filling period between genotypes were significant. Maximum and minimum seed filling rate was related to Karkheh genotype in 150 kg N.ha-1, and Verinak in treatment of using 50 kg N.ha-1. The effect of nitrogen levels on seed effective filling period was not significant. The maximum duration of seed filling was devoted to Verinak genotype and the minimum one was for Karkheh genotype. Chamran genotype, by using 150 kg N.ha-1, had maximum seed yield while Verinak genotype, using 50 kg N.ha-1 had minimum seed yield. Maximum 1000 seed weight was devoted to Karkheh genotype in treatment of using 150 kg N.ha-1, also the minimum 1000 seed weight was that of Star genotype in treatment of using 100 kg N.ha-1. The maximum seed protein percentage was observed at D-84-5 line, in 150 kg N.ha-1, and minimum amount of protein was in Chamran and Karkheh in 50 kg N.ha-1. A positive and significant correlation observed between seed yield and seed weight, the current photosynthesis rate and remobilization rate. In general, according to Khuzestan climate conditions, planting Chamran genotypes by using 150 kg N.ha-1, can led to an appropriate yield and it is highly suggested.