Genotypic Different In Nitrogen Use In Wheat

This study was carried out in the experimental farms in Yangzhou University during 2006-2008. The experiment was carried out by 36 wheat genotypes which were large-scale production in Jiangsu and some of them were new. To study the genotype difference of grain yield, the total nitrogen uptake, efficience of nitrogen use as well as quality characteristics under four nitrogen levels. With a view to provide a theoretical basis for efficient cultivation of wheat and for species selcction. The main results were as follows:(1) Under the four kinds of nitrogen fertilizer levels, there were significant genotypic differences in wheat grain yield .The genotype difference was largest under 0 N level and decreased with increasing of N level. The effect of nitrogen on increasing wheat grain yield decreased with increasing of N level. Increasing use of nitrogenous fertilizers can make a very significant increase in per panicle and grain number of each, but the weight decreased with the increasing use of nitrogen. Yangfumai 1 has reach to the maximum under 0 N level,while yangmai 15,yangmai 16,hong 3,you 18,xumai 27,huaimai 19 reach to the maximum under 9 N level.(2) Under the four kinds of nitrogen fertilizer levels, there were significant genotypic differences in the total nitrogen uptake of wheat during the whole growth period. The total nitrogen uptake of wheat increased when the using of nitrogen increased. Regardless of nitrogen level, N up take of 100 kilograms wheat was significant differences among genotypes. With the nitrogen level up, the 100-kilogram grain N uptake increased, genotypic difference was firstly declined then in a rising trend.As the nitrogen level rise, Nitrogen use efficiency of grain gradually increased, the genotypic difference in the levels of four kinds of nitrogen are significant, and become larger gradually; as the nitrogen level rise, the nitrogen marginal effect decreased, difference between genotypes gradually became smaller.(3) Under the four kinds of nitrogen fertilizer levels, grain protein content, as well as protein production increased with increasing of N level .The genotypic differences of grain protein content gradually become larger, while the protein yield showed an upward trend after the first drop.Grain amylopectin, amylose, as well as the ratio of amylopectin and amylose showed a rising trend with increasing of N level, but decline when nitrogen use is excessive. The genotypic differences of amylopectin was firstly increased and then decreased, the genotypic differences of amylose showed a downward trend, and the genotypic differences of the ratio of amylopectin and amylose was increased at first, then decrease. The genotypic differences of grain density decreased. Wet gluten content, sedimentation value of wheat increased with increasing of N level. But the increase extent became smaller, The genotypic differences increased at first, then decreased.Grain protein content, wet gluten content, sedimentation value of all test varieties has a significant positive correlation with nitrogen use, but amylose content, amylopectin content, grain density doesn't have a same correlation with nitrogen use.