| 1. Effects of irrigation after anthesis and nitrogen fertilizer on grain yield and qualityTwo wheat cultivars, JM20 and GH8901 with strong gluten content were used for investigating integrative effects of irrigation after anthesis and nitrogen on grain yield and quality by systematic experiments. The study focused on effects of irrigation after anthesis and nitrogen fertilizer on yield and yield composition, protein and protein components and dynamic changes, dough rheological properties, GMP, bread quality. The main results were as follows:1.1 Effects of irrigation after anthesis and nitrogen fertilizer on grain yield in strong-gluten winter wheatGrain yield including theoretical yield and actual yield under topdressing nitrogen was higher than that under non-topdressing nitrogen condition. Grain yield was increased, and then reduced with increasing the irrigation after anthesis. Grain yield of GH8901 reached the highest point in 3 times (90mm) irrigation treatment after anthesis, but grain yield of JM20 reached the peak level in 2 times (60mm) irrigation treatment after anthesis.1.2 Effects of irrigation after anthesis and nitrogen fertilizer on protein components contentProtein content and its components content increased in the early period and then decreased subsequently with more irrigation times after anthesis, but they gave different trends from various cultivars and diverse components of the same cultivar in irrigation treatments after anthesis. Monomeric protein content was higher in topdressing nitrogen treatment than that in non-topdressing nitrogen treatment. There was no effect from nitrogen fertilizer on soluble glutenin content of GH8901, but soluble glutenin content of JM20 was increased under topdressing nitrogen condition. There wasn't effect on insoluble glutenin content and glutenin of JM20, but insoluble glutenin content and glutenin of GH8901 increased in topdressing nitrogen treatment. Glutenins polymerization index of GH8901was higher under topdressing nitrogen condition than that non-topdressing nitrogen condition, but JM20's is the converse.1.3 Effects of irrigation after anthesis and nitrogen fertilizer on the granule size distribution characteristics of wheat grain GMPThe diameter of GMP particle was in the interval of 0.37 - 245μm, it changed in the pattern of double-peak curve in volume distribution, the first peak was at near 5μm of the diameter of GMP particle, the second peak was about 66~100μm. The percentages of volume of>100μm GMP particle were highest in irrigation 2 times treatment of JM20 after anthesis. While the percentages of volume of 10~100μm GMP particle reached the highest point in irrigation 2 times treatment of GH8901 after anthesis, the percentages of volume of>100μm GMP particle of these two cultivars were higher in topdressing nitrogen treatment than non-topdressing nitrogen.D(4,3) increased and then decreased with increasing the irrigation after anthesis, and it was the best in irrigation 3 times after anthesis for two cultivars. It changed in the pattern of single-peak curve in number distribution of GMP particle, the peak distribution of GMP particle appears at about 1μm, while M-type curve in surface area reached the peak point both at about 2μm and in the interval of 60~100μm. And D(3,2) showed the same change trend with D(4,3).1.4 Effects of irrigation after anthesis and nitrogen fertilizer on rheological properties of dough and bread volumeWet gluten content and water absorption had no distinct difference under different irrigation condition after anthesis for two cultivars, but protein content , dough stability time, dough development time and bread volume increased and then decreased subsequently with increasing the irrigation after anthesis. Protein content , dough stability time, dough development time and bread volume were the best under irrigation 2 times condition after anthesis for GH8901, while dough stability time was the best with irrigation 1 times after anthesis for JM20, but dough development time and bread volume had no difference with irrigation 1 or 2 times after anthesis.Protein content, wet gluten content, water absorption, dough stability time, dough development time and bread volume were better with topdressing nitrogen than non-topdressing nitrogen for two cultivars 1.5 Correlative analysis of the protein quality and rheological properties of dough and bread volumeTo GH8901, monomeric protein content, glutenin content and insoluble glutenin content were significantly correlative with the dough stability time; protein content, monomeric protein content, glutenin content, insoluble glutenin content, wet gluten content and dough stability time were significantly correlative with bread volume. To JM20, insoluble glutenin content was significantly correlative with the dough stability time; while glutenin content, soluble glutenin content, insoluble glutenin content and wet gluten conten were significantly correlative with bread volume, but protein content was not correlative with the dough stability time and bread volume.Stepwise correlation analysis suggested that the poor dough stability time resulted mainly from reduced insoluble glutenin content while the changes bread volume was resulted mainly from the changes glutenin content.2. Effects of irrigation time and volume after anthesis on grain yield and qualityTwo wheat cultivars, JM20 and GH8901, with strong gluten content were used to investigate integrative effects of irrigation times and volumes after anthesis on grain yield and quality under rainproof pond condition. The study focused on effects of irrigation treatments after anthesis on yield and yield composition, protein and protein components and dynamic changes, dough rheological properties, GMP, bread quality. The main results were as follows:2.1 Effects of irrigation post-anthesis on yield of winter WheatThe grain yield and weight per 10 3kernels of JM20 and GH8901 were improved by irrigation after anthesis, but the effect on grain yield was different with different irrigation periods and volume. The grain yield was higher with irrigation 1 or 2 frequency than 3 frequency after anthesis. The grain yield of JM20 decreased in 28 days irrigation after anthesis, and the grain yield was lower in the condition of 14 and 28 days than in 7days irrigation after anthesis. So it is adverse to the formation of production that excessive or too late was irrigated on filling stage2.2 Effects of irrigation after anthesis on protein components contentProtein content, gliadin content, albumin and globulin content were lower under irrigation than non-irrigation condition, but glutenin content and its compotents (soluble glutenin and insoluble glutenin) content were higher with irrigation than non-irrigation to JM20. Protein content, gliadin content, glutenin content and soluble glutenin content were lower with non-irrigation than irrigation 1 times, but they all were higher in non-irrigation than irrigation 3 times after anthesis. Insoluble glutenin content was lower with non-irrigation than irrigation after anthesis; but albumin and globulin content had no difference in various treatments of GH8901.High and low soluble glutenin content, soluble glutenin content were highest in 7+14 days irrigation condition after anthesis, and high and low insoluble glutenin content, insoluble glutenin content and glutenin content of JM20 were higher with irrigation 1 times than irrigation 2 or 3 times after anthesis. Protein content, High and low soluble glutenin content, glutenin content, gliadin content, albumin and globulin content were highest in 14 days irrigation condition after anthesis, but high and low insoluble glutenin content, insoluble glutenin content of GH8901were highest in the condition of 7+14 days irrigation after anthesis.With different irrigation times and volume analysis for two cultivars, protein content and its compontents content were better under the condition of irrigation 1 or 2 times after anthesis.2.3 Effects of irrigation after anthesis on glutenin subunitHMW-GS content for two cultivars was lower in non-irrigation than irrigation once. Under the condition of irrigation once, HMW-GS content reached the highest level with irrigation 14 days after anthesis, while under irrigation twice condition, it was highest in irrigation 7+14 days after anthesis treatment. With different irrigation volume, HMW-GS content was the highest in the case of irrigation once for two cultivars, while LMW-GS contents weren't different in diverse irrigation treatments.2.4 Effects of irrigation after anthesis on the granule size distribution characteristics of wheat grain GMPThe distribution characteristics of particle size of GMP was consistent in different irrigation treatments, and the peak was also consistent with the scope, but the particle size distribution of volume and surface area showed some differences in various irrigation treatments. Under the experimental conditions, the particle size of volume and surface area were higher in irrigation 1 times than 2 or 3 times treatments of two cultivars, and GMP particle size D (4,3) and D (3,2) reached the peak level in the treatments of irrigation 7 days after anthesis.2.5 Effects of irrigation after anthesis on rheological properties of dough and bread volumeWet gluten content and water absorption had no significantly difference under different irrigation after anthesis of two cultivars, but effects were distinct on dough stability time. Under irrigation once condition, the difference of dough stability time wasn't distinct, but under irrigation twice condition dough stability time and development time were better in the case of irrigation 7+14 days after anthesis of JM20, but they had no significantly deffernce of GH8901. Dough stability time was the best in the treatments of irrigation 1 times after anthesis of these two cultivars.Under irrigation once condition, bread volume was the best in the case of irrigation 14 days after anthesis. It was best in the treatment of GH88901 with irrigation 7 days after anthesis; under irrigation twice condition, bread volume was the best in the case of irrigation 7+14 days after anthesis of JM20. Under different irrigation volume condition, bread volume was better in irrigation condition of 1 or 2 times than irrigation 3 times after anthesis of JM20, but it was the best in the treatment of irrigation 2 times after anthesis of GH8901.2.6 Correlative analysis of the protein quality and rheological properties of dough and bread volumeTo JM20, Bread total score and wet gluten content were no significantly correlative with protein content and its components, but glutenin content and the ratio of glutenin and gliadin were significantly correlative with bread volume. Polymerization index(insoluble glutenin/total glutenin), insoluble glutenin content, high and low insoluble glutenin content, HMW-GS content, D(4,3) were significantly correlative with the dough stability time; and insoluble glutenin content, polymerization index , high and low glutenin content, glutenin content and the ratio of glutenin and gliadin were still significantly correlative with the dough development time.To GH8901, insoluble glutenin content, polymerization index, low insoluble glutenin content and the ratio of glutenin and gliadin were significantly and positively correlative with bread volume; but gliadin content was significantly and negatively correlative with bread volume. Gliadin content, albumin and globulin content and wet gluten content were significantly and negatively correlative with bread total scores. HMW-GS content was significantly and positively correlative with dough stability time, but water absorption was significantly and negatively correlative with dough stability time, and HMW-GS content was also significantly and negatively correlative with water absorption.Stepwise correlation analysis suggested that the poor dough stability time resulted mainly from reduced insoluble glutenin content and GMP, but the changes bread volume resulted mainly from the changes glutenin content and wet gluten content.
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