Effect Of Potassium Split Application On Grain Yield And Quality Of Strong-gluten Winter Wheat

Field studies were conducted at the experimental farm of Shandong AgriculturalUniversity in two successive seasons (2010-2012) using four winter wheat cultivars (JM20,GC8901, YN19and JN17) and three regimes of K fertilization (K0: no K fertilization; KB:basal K fertilization; KS: split application K fertilization) for researching the effect of splitapplication K fertilization on the grain yield and wheat quality. The mainly results are below:1Effect of different potassium applications on the dynamics curve of grain protein andits components content in filling processThe results showed that the accumulation of crude protein content showed a "V"-shapedcurve in the grain filling process. At the early grain filling stage, the content of grain proteinshowed a downward trend. At the20th Day after anthesis (DAA) the content reduced tominimum, and then protein content rose rapidly until the end of the grain filling. Albumin andglobulin content continued to decrease during the grain filling process. From15DAA to20DAA the globulin decreased faster, and after20days flowering, the rate of downward trendslowed down. The accumulation of gliadin content showed a "V"-shaped curve in the grainfilling process, but the change is smaller. At the different potassium fertilization conditions,the content of glutenin changed significantly. From0DAA to20DAA the content of gluteninshowed a downward trend, and the difference between potassium treatments is small. At thelate stage of grain filling, the content of grain glutenin increased significantly.The trends of SDS-soluble glutenin and SDS-insoluble glutenin content accumulation aresame, which showed a decrease trend at first and then increased. The treatments withpotassium had a faster accumulation of SDS-insoluble content, at the late stage of fillingphase, and there was a significant difference between potassium treatments, which could notbe observed in SDS-soluble glutenin. During the grain filling, the content ofHigh-molecular-weight glutenin subunit (HMW-GS) had a slight decrease at the early stage,and then had a continued increase, until the end of the filling. The HMW-GS content ofpotassium split application is significant higher then other treatments. 2Effect of different potassium applications on grain yield and componentsThe experiment results of four cultivars in two years are consistent, which showed thatthe yield of wheat with potassium fertilization could be increased, and that the grain yield ofspilt application potassium is highest. Compared with K0, the1000-kernel weight and spikenumbers of K1and K2had a significant increase. Compared with K1, K2increased yield byimproving the1000-kernel weight of grain.3Effect of different potassium applications on the content of grain potassium andprotein components.Split application potassium could increase the content of grain potassium significantly,but we could not observe the significant difference of grain potassium content between K1and K0. The content of crude protein, Albumin and globulin in K1and K2are significanthigher than K0, but they were not significant between K1and K2. Split application potassiumcould increase the content of glutenin, and decrease the content of gliadin at the same time,which caused the improving of glutenin/gliadin ratio. Compared with K1, we could notobserve the content of SDS-soluble glutenin increasing significantly in K2, but we couldobserve the increasing of SDS-insoluble content. The increase of SDS-insoluble content wasbenefit for increasing the polymerization index of glutenin. The result showed that thepolymerization index of K2is higher then K0and K1.4Effect of different potassium applications on the content of glutenin subunits in grainThe experiment results of four cultivars in two years are consistent, which showed thatpotassium application could significantly increase the content of HMW-GS and LMW-GS,and the ratio of HMW-GS/LMW-GS. The results showed that split application potassium wasbetter.5Effect of different potassium applications on the granule size distribution of GMPPotassium application could significantly increase the percentage of the gluteninmacro-polymer (GMP) particles, which size was bigger then100μm, and reduce thepercentage of the GMP particles that smaller then10μm at the same time. The percentage ofthe GMP particles that the size between10-100μm was different in different cultivars andyears. The weighted average volume of GMP particles and Weighted average surface area ofGMP particles could reflect the status of GMP particles better. The result showed that split application potassium could improve the average volume and surface of GMP particles, whichwas benefit for the formation of bigger GMP particles.6Effect of different potassium applications on dough quality and bread qualityThe experiment results of four cultivars in two years are consistent, which showed thatpotassium application could increase the dough development and stability time, and thevolume of bread significantly. The result showed that K2is optimal treatment. There aresignificant differences in the indicators for different cultivars. The effect of potassiumapplication on flour wet gluten content is small, and we could not observe the significantdifference.7Correlation analysis between the protein quality and the dough and bread qualityThe correlation analysis showed: SDS-insoluble glutenin content, polymerization index,glutenin/gliadin ratio, D (4,3) and D (3,2) significantly and positively correlated withdough development time, dough stability time, and loaf volume. SDS-soluble glutenin contentand gliadin content negatively correlated with quality indicators. We could not observe thecorrelation between crude protein and wheat quality indicators.8Correlation analysis between the content of glutenin subunits and the granule sizedistribution of GMPThe result showed: HMW-GS content, HMW-GS/LMW-GS ratio significantly andpositively correlated with D (4,3), D (3,2), and>100μm particle percentage. HMW-GScontent, HMW-GS/LMW-GS ratio significantly and negatively correlated with <10μmparticle percentage, and they had no correlation with10-100μm particle percentage. We couldnot observe the correlation between LMW-GS content and indicators of the granule sizedistribution of GMP.9Regression analysis between the protein quality and the dough and bread qualityRegression analysis showed: in different potassium application treatment, the changes ofdough stability time were led by the changes of glutenin/gliadin ratio, and the changes of loafvolume resulted mainly from the changes of polymerization index.