Effects Of Sowing Date And Sowing Density On Yield Formation,Quality And Growth Of Shannong 33 Under Late Sowing Condition In Nanyang Area

Due to the limitations of previous crops and weather,late sowing has become a common phenomenon in current wheat production.The suitable sowing time of wheat used in the past can not meet the needs of actual production.However,the trend of global warming also makes it possible for late sowing to stabilize the yield.In order to explore the effect of sowing date and density on yield and quality under late sowing condition,and to explore the supporting cultivation technology of the new wheat variety Shannong 33,so as to determine the critical date of late sowing and the suitable combination of sowing date and sowing density.In this experiment,Shannong 33 was used as the material in 2019-2021 in Wolong Farm,Liaohe Town,Nanyang City,Henan Province,and the effects of different sowing dates and densities on wheat yield,quality,population quality and carbon and nitrogen transport under late sowing conditions were studied by using split plot experiment design.The main results of this experiment were as follows:(1)The results of two years showed that sowing date had a significant effect on yield.There were slight differences from year to year,but it was basically the same.After the end of October,the yield decreased significantly.With the increase of the sowing density,the yield increased first and then decreased.In 2019-2020,grain number per spike and 1000-grain weight decreased significantly with the delay of sowing date.In 2020-2021,with the increase of sowing density,spike number per unit area increased,but grain number per spike decreased.(2)The data from 2020-2021 showed that protein content had a significant positive correlation with wet gluten content,stability time,settling value,and appropriate late sowing(around October 31)was conducive to improving the above indexes.Two years’data showed that sowing after the end of October was not conducive to the stability of the above quality indexes.The suitable sowing density was about 2.4-3 million basic seedlings/hm~2.The amylose content decreased with the delay of sowing date,but the expansion potential and peak viscosity were contrary,The peak viscosity decreased significantly when the sowing density was more than 3 million basic seedlings/hm~2.It can be concluded that when the sowing date was late and the sowing amount was less than 3 million basic seedlings/hm~2,the noodles made from wheat flour were relatively high quality.According to all quality indexes,suitable late sowing(around October 31)and sowing a appropriate sowing density of 2.4-3 million basic seedlings/hm~2,which was conducive to the high quality production of Shannong 33.(3)Tiller number and dry matter accumulation increased first and then decreased with the postponement of sowing date,but there was no significant difference in late growth period.The density of dry matter accumulation after anthesis and the contribution rate of dry matter to grains increased first and then decreased with the delay of sowing date;When the sowing density was more than 3 million basic seedlings/hm~2,the ratio of productive tiller and economic coefficient were lower,which will increase the material consumption of ineffective tillering and was not conducive to high yield.(4)The sowing date and sowing density has significant influence on plant various morphological index,flag leaf length and the second leaf and the third leaf width and area,the total number of spikelets,the number of fruiting spikelets,spike length,basal internode diameter and thickness of the first interstitial wall of the base were significantly lower in S3(November 6)than S1(25 October)and S2(October 31);The basal internode diameter and the thickness of the first interstitial wall of the base both decreased with the increase of sowing density.Combined with the positive correlation between stem lodging resistance and basal internode diameter and wall thickness,it could be concluded that wheat was not easy to lodging when sowing before the end of October and the sowing density was less than 3 million basic seedlings/hm~2.In conclusion,the critical late sowing period of Shannong 33 in Nanyang area was about October 31,and the suitable sowing density was 2.4 to 3 million basic seedlings/hm~2.