Abstract:Effects of nitrogen application amounts on protein components contents and glutenin subunits (HMW-GS, LMW-GS) of wheat genotypes with different qualities, namely Jimai 20 (strong gluten), Taishan 23 (middle gluten) and Ningmai 9 (weak gluten) were studied by reversed-phase high-performance liquid chromatography (RP-HPLC), and the relationships between protein components contents and processing quality were analyzed. Results show that total protein content and its components contents are increased at first and then decreased with the increase of nitrogen application amounts for Jimai 20 and Taishan 23. The protein components contents are higher and the processing quality is better under the treatment of applying nitrogen at N 240 kg/ha, while HMW-GS is retrained synthesis under the excessive nitrogen fertilization, which is one of reasons which decrease protein quality for strong and middle gluten wheat. With the increase of nitrogen application amounts, all protein components contents for Ningmai 9 are significantly increased and processing quality become poor. On the condition of applying nitrogen fertilizer for the three cultivars, the increased extents of glutenin and gliadin contents are significantly higher than those of albumin + globulin contents, which is an important reason to improve strong and middle gluten wheat grain protein quality with applying nitrogen fertilizer. Total protein and gliadin contents are not significant different between Jimai 20 and Taishan 23, and glutenin, gluten protein, HMW-GS, LMW-GS and GMP contents, and the ratios of HMW/LMW and Glu/gli of Jimai 20 are higher than those of Taishan 23, which is an important reason for Jimai 20 obtaining higher dough development time and dough stability time than those of Taishan 23.