Effect Of Nitrogen Application Stage To Spatial Distribution Characteristics Of Quality Traits In Wheat Grain

Effects of nitrogen strategies on variations in quality traits within different pearling fractions in wheat grains were studied based on field experiments from2009-2010,4kinds of medium-gluten winter wheat cultivars AK58,09-82, Jimai22and Xumai30were used to explore effect of post-anthesis foliar nitrogen application on variations on quality traits within different pearling fractions and from2010-2012, Xumai7086(high-gluten wheat) were used to study effect of nitrogen applying leaf ages (including2spring-leaf stage,4spring-leaf stage,5spring-leaf stage, flagleaf stage and anthesis stage) on quality traits within different pearling fractions. The main results were as follows:1. Spatial distribution characteristics of quality traits in wheat grainsSix or nine pearling fractions (P1-P8-9/P9fractions) of wheat grain were obtained using two rice polishers. The results show that protein content and its components showed a diminishing trend as pearling progressed from the outer player (P1fraction) to the inner part of wheat grain (P8-9P9fraction) and the P1fraction (the outer0-10%layer of wheat grain) had the highest albumin and globulin contents, whereas the P2fraction (the outer10-20%layer of wheat grain) had the highest glaidin and glutenin contents. Contents of GMP and HMW-GS both showed similar variation trends with the content of protein and the P2fraction had the highest Glu-D1content while the P3fraction (the outer20-30%layer of wheat grain) ranked the highest for GMP, Glu-A1and Glu-Bl contents. Besides, the spatial distribution characteristics of starch were different with that of protein. Contents of amylose, amylopectin and total starch showed an increasing trend as pearling progressed from the outer player to the inner part of wheat grain and the flour viscosity showed a similar variation trend.2. Effect of nitrogen applying leaf ages on quality traits within different pearling fractions in wheat cultivar Xumai7086Globulin, glutenin and total protein within P1-P5fractions and gliadin within P1-P9fractions increased with delaying of N supply stage and reached maximum at flagleaf or anthesis stage (P1-P5fractions) and4spring-leaf stage (P6-P9fractions). Content of GMP within P1-P5fractions increased with delaying of N supply stage and reached maximum at flagleaf stage, second by anthesis and5spring-leaf stage. N application stages had significant influence on HMW-GS content. Content of Glu-A1, Glu-B1, Glu-D1and total HMW-GS within all pearling fractions first increased then decreased with delaying of N supply stage and reached maximum at5spring-leaf stage. Besides, delaying of N supply stage decreased starch content and pasting properties, while increasing sedimentation value, falling number and swelling power, and the best N applying stage seemed to be flagleaf stage.3. Effect of post-anthesis foliar nitrogen application on variations on quality traits within different pearling fractions in grains of different wheat cultivarsPost-anthesis foliar nitrogen spray significantly increased1000-kernel weight of wheat09-82and AK58, while increasing protein content and its components within different pearling fractions of different wheat cultivars. Besides, contents of GMP and HMW-GS within different pearling fractions increased at different degrees. Post-anthesis foliar nitrogen application has no obvious increase of starch content and its components, and the changes of processing quality traits were not consistent in different wheat cultivars. According to the different quality traits, we selected the most sensitive species to nitrogen. The most sensitive varieties improving protein content and its components were wheat cultivar09-82of outer layers (P1-P2fractions), Jimai22of transition layer (P3fraction) and Xumai30of inner layers (P4-5-P8-9fractions).The most sensitive varieties improving starch content and its pasting properties were Xuami30of outer layers and transition layer and Jimai22of inner layers. Wheat cultivar AK58was the most sensitive variety to nitrogen in SDS value, besides the most sensitive varieties improving falling number and swelling power were AK58of outer layers and Jimai22of transition layer and inner layers.