Abstract: Seven varieties of strong gluten wheat were cultured in six provinces to study stability and regulation effects of N-fertilizer on grain yield and protein content. The results showed that within the range of 0~300Kg/hm2 N fertilizer level, the grain yield of different varieties increased with the amount of N-fertilizer added in different experimental farm. The yields of among the treatments fertilized were remarkable level, but the applied N 300 Kg/hm2 increased 1.6% than 225 Kg/hm2. The CV of yield of different treatment had a trend of decrease with the amount of N-fertilizer added in different experimental farm. It showed that N-fertilizer could lessen the deference of area. Some varieties ware more sensitive to N-fertilizer, its grain yield increased obviously with added N-fertilizer, others were better for stable yield. The CV of protein content had the same trend with grain yield. It indicated that applied nitrogen properly could decrease the deference of protein content in different experimental area. The more CV was small the more protein content was stable, the more CV was biggish the more cultivate plasticity was better. The protein content of All varieties was sensitive to N-fertilize in the experiment, under 150 Kg/hm2 fertilizer level, the protein content of some varieties couldn’t reach the national standard of strong gluten wheat, beyond the level of 225Kg/hm2, all of the varieties could reach it in the experiment. Consider of yield and quality, the N-fertilizer level of strong gluten wheat should be 225~300Kg/hm2in practice. The cultivation measure > genotype > entironment in the factors that influencethe grain protein content in the experiment.

Key words: strong gluten wheat, yield, protein content, stability