Indexes Screening Evaluating Grain Quality Of Weak-gluten And Medium-gluten Wheat And Their Regulating Techniques For Good-quality And High-yield

The demand for high-quality wheat flour is increasing with the improvement of living standards,but the quality of the produced wheat flour is not stable,while the high-quality weak-gluten wheat flour largely depends on imports.Jiangsu province is the main production area of red and weak-gluten wheat.In this area,the weak and medium gluten wheat is the key target of quality improvement.The experiment was carried out in Haian City,Nantong and Xinghua City,Taizhou from November 2017 to June 2019 with a weak gluten wheat cultivar,Ningmai 13,and a medium-gluten wheat cultivar,Yangfumai 4.The present study set different planting density,nitrogen rate,and nitrogen regime to investigate the effects of different combinations of planting density and nitrogen application on yield components,processing quality,and the stem carbon metabolism,and to analyze the relationships between different grain quality indexes and between stem carbon metabolism and the formation of yield and quality.The expected aims included studying the evaluation indexes of different types of wheat and proposing suitable regulation measures to provide theoretical basis and technical supports for realizing high yield and quality of weak gluten and medium gluten wheat.The main results were as follows:1.The principal component analysis was used to select the key factors,classify the grain quality indexes,and propose the main index contributing to grain quality formation.Under the experimental conditions,the lactic acid solvent retention capacity(SRC),sucrose SRC,grain protein content,stabilization time,softening degree,cookie spread ratio,trough viscosity,final viscosity,and farinograph quality number were screened as the traits evaluating the quality of weak gluten wheat Ningmai 13 with SRC and farinograph parameters as the key indexes.The peak viscosity,trough viscosity,final viscosity,farinograph quality number,hardness index,grain protein content,total score,and noodle flavor were screened as the traits evaluating the quality of medium-gluten wheat Yangfumai 4 with gelatinization properties and noodles quality as the key indexes2.The dough toughness of weak gluten wheat Ningmai 13 was stronger than extensibility.Under the condition of low and middle planting densities,the grain protein content,wet gluten content,and stabilization time increased with the increase of nitrogen application,but cookie spread ratio decreased.High planting density relieved the effects of high nitrogen application,showing that the grain protein content,test weight,and hardness index had a downward trend with the increase of nitrogen application,but cookie spread ratio decreased,but stabilization time shortened.The dough extensibility of medium gluten wheat Yangfumai 4 was stronger than toughness.Under the condition of low planting densities,the grain protein content,wet gluten content,stabilization time,and noodles quality were increased with the increase of nitrogen application.Under the condition of middle and high planting densities,wet gluten content were increased with the increase of nitrogen application,but stabilization time shortened,while the grain protein content and noodles total score showed a trend of increase and then decrease.3.With the increase of planting density,stem and tiller number,leaf area index(LAI),and dry matter accumulation of Ningmai 13 were increased,but spike and tiller fertility decreased.Too many wheat plants could cause a decline of grain yield,spike number,and grain weight.Under the condition of low and middle planting densities,grain yield,stem and tiller number,LAI,and dry matter accumulation were increased with the increase of nitrogen application,while postponing nitrogen topdressing further improved these parameters.The stem and tiller number,LAI,and dry matter accumulation of Yangfumai 4 shown an increasing trend with the increased planting density,and spike number and grain yield increased,but the stem and tiller fertility showed a decreasing trend.The stem and tiller number,LAI,dry matter accumulation,and spike number were increased with the increased nitrogen rate,but grain number per spike had a downward trend.The nitrogen application ratio of 5:1:2:2 improved spike number,grain number per spike,and 1000-grain weight in comparison to 7:1:2:0.4.The yield structure and population characteristics of Ningmai 13 facilitating good quality and high yield included spike number of 490×104·hm-2,45-46 grains per spike,1000-grains weight of 40-44 g,38%-43%stem and tiller fertility,6.7-6.8 LAI at booting,5.5-6.0 LAI at anthesis,10000-12200 kg·hm-2 dry matter accumulation at anthesis,and14400-18000 kg·hm-2 dry matter accumulation at maturity.The yield structure and population characteristics of Yangfumai 4 facilitating good quality and high yield included spike number of 378-390×104·hm-2,45-46 grains per spike,1000-grains weight of 43-47 g,40%-44%stem and tiller fertility,5.5-6.3 LAI at booting,4.8-5.3 LAI at anthesis,8700-11000 kg·hm-2 dry matter accumulation at anthesis,and13000-16000 kg·hm-2 dry matter accumulation at maturity.5.The soluble sugar content in stem and sheath was the highest under the middle nitrogen application compared with other level nitrogen rates,which also could be improved with postponing nitrogen fertilizer.Increasing planting density decreased soluble sugar content.The activities of PEPC,SPS,and SS reached its peak at 7 days,14 days,and 21 days after flowering,respectively,and were higher under 240 kg/hm2 nitrogen application than other nitrogen rates.The distribution amount of total soluble sugar and its contribution percentage to grain yield of Ningmai 13 was increased with the increase of planting density.The middle and high nitrogen application achieved a relatively higher redistribution amount of total soluble sugar and its contribution to grain yield.There existed a significant positive relationship between grain starch content and redistribution amount of total soluble sugar in the stem and sheath.The redistribution amount of total soluble sugar in the stem and sheath and its contribution percentage to grain starch yield of Yangfumai 4 was increased with the increase of planting density.The middle and high nitrogen application improved the redistribution amount of total soluble sugar and its contribution to grain yield.The activities of total soluble sugar,PEPC,and SS in the stem and sheath had a significantly positive relationship with the contents of starch.6.Under the specific climate and production condition of this experiment,the cultivation measures of weak-gluten wheat cultivar Ningmai 13 achieving good quality and high yield include 300×104·hm-2 planting density,240 kg·hm-2 nitrogen application,and nitrogen application ratio of 5:1:2:2,or 300×104·hm-2 planting density,240 kg·hm-2 nitrogen application,nitrogen application ratio of 7:1:2:0,while combining 105 kg·hm-2 P2O5 and 105 kg·hm-2 K2O separately applied 50%as basal and jointing fertilizer.The cultivation measures of medium-gluten wheat cultivar Yangfumai 4 achieving good quality and high yield include 225×104·hm-2 planting density,270 kg·hm-2 nitrogen application,and nitrogen application ratio of 5:1:2:2,or 300×104·hm-2 planting density,240 kg·hm-2 nitrogen application,nitrogen application ratio of 5:1:2:2,while combining 105 kg·hm-2 P2O5 and 105 kg·hm-2 K2O separately applied 50%as basal and jointing fertilizer.