Effects Of Sowing Date And Planting Density On Yield And Quality Of Wheat Varieties With Strong Gluten

Suitable sowing date and planting density are important factors for the coordinated improvement of wheat grain yield and quality,but the response of grain yield and quality to sowing date and density was not the same in different wheat varieties.Six wheat varieties with strong gluten content,Kexing 3302,Yuzhou 473,Yuzhou 116,Yuzhou114,Yuzhou 118 and Xinmai 26,were used under two sowing dates,October 18(S1)and October 28(S2),and five planting densities(basic seedlings)with D180,D225,D270,D315 and D375 as 180×104/hm2,225×104/hm2,270×104/hm2,315×104/hm2,and 375×104/hm2 respectively.The effects of different sowing dates and planting densities on wheat plant physiological indexes,grain yield and its components,starch properties and flour processing quality were studied.The main results are as follows:(1)Effects of sowing date and density on physiological indexes of wheat plantsUnder the same sowing date,the chlorophyll content of each wheat variety was significantly different among different planting densities,and most of them reached the maximum value at the lower density treatment.With the delay of sowing date,the flag leaf chlorophyll content of the tested varieties showed an increasing trend,with the value under S1 sowing date lower than S2 sowing date.The NDVI value of wheat plants increased first and then decreased with the growth stage,and most of the wheat varieties reached the maximum value at booting stage;With the delay of sowing date,NDVI value under S2 sowing date is lower than that in corresponding S1 sowing date.With the increase of planting density,NDVI increased.At jointing stage under S1 sowing date,the NDVI of tested wheat varieties under D375 treamtent increased by 4.22%,4.59%,15.15%,13.39%,3.26% and6.51% respectively,compared with D180.Under S2 sowing date,the correspondingly increase was by 14.72%,4.83%,4.68%,7.49%,19.76% and 12.22% respectively.(2)Effects of sowing date and density on dry matter and nitrogen accumulation of wheat plantsWith wheat growing development,the dry matter accumulation gradually increased,and the dry matter accumulation from the jointing stage to the flowering stage showed a linear growth trend,and reached the maximum at the mature stage.With delay of sowing date,the dry matter accumulation of wheat showed a downward trend,and the difference between treatments was significant.Under the two sowing dates,the dry matter accumulation of wheat was D375>D315>D270>D225>D180.The nitrogen accumulation of plant also increased with the increase of density,showing as D375>D315>D270>D225>D180.At the same sowing date,the amount of nitrogen accumulation in grains increased with the increase of planting density,while the amount of nitrogen absorbed from grains after anthesis and its contribution rate decreased with the increase of planting density.Under the same density,grain nitrogen accumulation amount,nitrogen transport amount,transport rate(except D375 density treatment)and contribution rate of stored nitrogen in pre anthesis vegetative organs were S1>S2.However,the absorption amount of nitrogen in grains after anthesis and the contribution rate of nitrogen to grains were S1<S2.(3)Effects of sowing date and density on yield and yield components of different wheat varietiesThe yield of the tested wheat varieties was S1>S2.The optimum density for high yield of different varieties was different.The highest grain yield of Kexing 3302 and Yuzhou 473 was observed under D375 density treatment,whereas the highest yield of Yuzhou 114 and Yuzhou 118 was under D270 treatment.Yuzhou 196 and Xinmai 26 had the highest grain yield under D375 treatment at S1 sowing date,while they got the highest yield under D270 and D315 at S2 sowing date.The number of spikes increased with the increase of planting density,while the number of grains per spike and 1000-grain weight decreased.With the delay of sowing date,the number of spikes decreased,and the number of grains per spike and the 1000-grain weight increased accordingly.In general,most varieties have the highest yield under S1(October18)sowing date and density D315~D375.(4)Effects of sowing date and density on starch characteristics of different wheat varietiesThe total starch content of the tested varieties was 83.89-90.20%,the amylose content was 18.18-26.58%,and the amylopectin content was 59.57-68.93%.In low density planting,the total starch content was S1>S2,whereas the total starch content showed S2>S1 under high density planting.The content of amylose increased with the delay of sowing date.The amylose content of Kexing 3302 got the highest value under D375 treatment under two sowing dates,with 24.78% and 25.61%,respectively.The total starch content of Kexing 3302,Yuzhou 196,Yuzhou 114 and Xinmai 26 wheat varieties was D180>D225>D315>D270>D375 in S1 sowing date.The effect of density treatment on amylopectin content was the highest in Yuzhou 118 and the lowest in Yuzhou 114,with the maximum difference of 10.58% and 1.36% respectively.The starch pasting characteristics of different varieties have different responses to sowing date and density.The peak viscosity,through viscosity and final viscosity of Kexing 3302,Yuzhou 196(S1)and Yuzhou 473(S1)increased with the increase of density,whereas these three indexes of Yuzhou 114,Yuzhou118 and Xinmai 26 increased first and then decreased with the increase of planting density.(5)Effects of sowing date and density on flour processing quality of different wheat varietiesWith the delay of sowing date,the dough developing time and stability time of most of the tested wheat varieties increased,showing S1<S2.However,the extensibility of dough decreased.With the increase of planting density,the dough extension area and the maximum dough extension ratio increased first and then decreased.In general,the stability time and extension area of all wheat varieties under different densities and sowing dates reached the standard of strong gluten wheat according to National Standard for Strong Gluten Wheat.The stability time of all the tested wheat exceeded 10 min except for Yuzhou 118(S1),while stability time of Xinmai 26,Kexing 3302,Yuzhou 473 and Yuzhou 196 exceeded 20 minutes.The results showed that for the strong gluten wheat varieties in this study,the regulation effect of sowing date density on yield was greater than that on quality,which indicate that the key to achieve high yield and improvemen quality lies in appropriate sowing date and density to increase yield.