Effects Of Different Sowing Rates On Wheat Yield And Population Quality In Central Henan Province

In order to study the effects of different sowing rates on wheat yield formation and yield components,Under the field conditions,set different cultivars of Bainong207,Zhoumai27,Zhengmai7698 and Zhongmai895 as experimental materials,nine sowing locations respectively in Zhengzhou、Shangqiu、Changge、Shangshui、Xihua、Linyin、Nanyang、Weishi and Zhumadian,and five densities(112.5 kg/hm~2(D1),150 kg/hm~2(D2),187.5 kg/hm~2(D3),225 kg/hm~2(D4),and 262.5 kg/hm~2(D5).The main research results are as follows: 1 Effects of different sowing rates on wheat yield and yield componentsThe summary analysis of different cultivars and locations showed that the average wheat yield was 225 kg/hm~2(D4).Among different locations,the highest yields were all obtained at 225kg/hm~2(D4)in Zhengzhou,Shangqiu,Xihua,Changge,Linyi and Weishi,but were obtained at 187.5kg/hm~2(D3)in Shangshui and Zhumadian,and 150kg/hm~2(D2)in Nanyang.On yield components,the earbearing tiller increased with the increase of sowing rate,while grains per spike and 1000-grain weight decreased slightly when the sowing rate increased,and there were no significant difference between treatments.Based on the above results,the suitable sowing rates in central Henan was between 150kg/hm~2 and 225kg/hm~2.2 Effects of different sowing rates on wheat population structureWith development of wheat development,the number of stems and stalks of the population increased first and then decreased,which reached the peak at jointing stage.The number of stems in different wheat cultivars increased with the increase of sowing rates.In the maximum stem stage(jointing stage),the stems number of Bainong 207,Zhoumai 27,Zhengmai 7698 and Zhongmai 895 reached: 1965.83plants/hm~2,1760.83 plants/hm~2,1738.33plants/hm~2 and 2010.83plants/hm~2,The final percentage of earbearing tiller decreased significantly with the increase of sowing rate.Compared with D1,the percentage of earbearing tiller of Bainong 207,Zhoumai 27,Zhengmai 7698 and Zhongmai 895 D5 decreased by 20.1%,17.8%,15.6% and 26%;The peak of leaf area index appeared in the booting stage,and LAI increased with the increase of sowing rate.The maximum leaf area index of Bainong 207,Zhoumai 27,Zhengmai 7698 and Zhongmai 895 was respectively 9.03,8.93,7.77 and 8.38.3 Effects of different sowing rates on wheat dry matterThe accumulation of dry matter also increased with the increase of sowing rate among different sowing treatment,which reached the maximum at maturity.Increasing the sowing rate had a significant effect on the amount of dry matter transportation before flowering,the contribution rate of grain and the amount of grain input post-anthesis,but had no significant effect on the contribution rate of post-anthesis assimilates to grain.4 Effect of different sowing rates on wheat SPAD valueThe SPAD value of wheat leaves increased first and then decreased with the progress of growth period and the peak appeared in flowering stage.Among different cultivars,the SPAD value was all smallest at the highest density of D5 treatment,among them,Bainong 207 the SPAD value(flowering period)was highest at D4,which was 5.92% higher than D5 treatment;Zhoumai 27 and Zhengmai 7698 were highest at D3,compared with D5 treatment,the value increased by 16.67% and 20.39% respectively;Zhongmai 895 was highest at D2,which was 26.1% higher than D5 treatment.5 Effects of different sowing rates on Nitrogen accumulation and transpotation in WheatThe nitrogen accumulation of Bainong 207,Zhoumai 27,Zhengmai 7698 and Zhongmai 895 increased from emergence to jointing,jointing to flowering with the increase of sowing rate;from flowering to maturity,nitrogen accumulation of four cultivars all decreased with the increase of the sowing rate;at the maturity stage,the nitrogen accumulation of the four wheat cultivars increased with the increase of the sowing rate.About the nitrogen accumulation of grain,Bainong 207 was highest at D5,which increased by 30.36% compared with D1 treatment.The treatment of Zhoumai 27,Zhengmai 7698 and Zhongmai 895 was all t highest at D4 treatment,minimum at D1 treatment,and D4 was increased by 41.39%,21.74% and 20.55% respectively compared with D1.About the amount of nitrogen transportation before flowering,and the valuer of Bainong 207 was highest at D5 treatment,and it increased by 85.43% compared with the minimum D1 treatment;Zhoumai 27,Zhengmai 7698 and Zhongmai 895 were highest at D4 treatment,D1 treatment was the minimum,D4 increased by 73.51%,41.11% and 59.59% respectively compared with D1.The contribution rate of nitrogen contribution before flowering increased with the increase of sowing rate;the nitrogen transportation capacity and contribution after flowering of four cultivars showed a trend of decreasing with the increase of the amount of sowing,showed that D1>D2>D3>D4>D5,and there was significant difference among treatments.