Effect Of Nitrogen Application On Lodging Resistance Of The Third Internode Of Winter Wheat

The lodging of Winter Wheat in Huang Huai Hai region is one of the main factors to reduce the yield and grain quality of wheat.Based on the previous field investigation,it was found that there was a certain proportion of lodging in the third internode of wheat base.In order to find out the relationship between the lodging rate of the third internode and the first and second internode,and the influence of the content and proportion of cellulose and lignin in the stem on the lodging resistance of the third internode of wheat base,this study used Yannong 19 and Xinmai 26 as experimental materials,and carried out different nitrogen fertilizers under the field conditions of Mengcheng agricultural demonstration field in Anhui Province The effects of operation methods on the lodging resistance of the third internode of winter wheat were studied.The amount of nitrogen application was 135（N1）,180（N2）,225（N3）and 270（N4）kg·hm^-2,and the ratio of nitrogen base to topdressing was 10:0（R1）,7:3（R2）,5:5（R3）and 3:7（R4）,respectively.The results show that:1.From flowering stage to waxing stage,the wall thickness,fullness,mechanical strength and lodging resistance index of the third internode of the two varieties decreased,while the height of the center of gravity increased significantly,indicating that the lodging resistance of the third internode of the wheat base decreased from flowering stage to waxing stage,and the lodging of the third internode may occur.2.The application of nitrogen fertilizer significantly affected the occurrence of lodging in the third internode of winter wheat,and increased application of nitrogen fertilizer would reduce the lodging resistance of the third internode.Increasing the proportion of top dressing at the jointing stage is conducive to improving the lodging resistance of the third internode.In addition,the internode diameter,stem wall thickness,mechanical strength and lodging resistance index of the third internode all reached the maximum value under the third internode,which indicated that the lodging resistance of the third internode was the strongest under the third internode.3.The third internode lodging rate was positively correlated with the second internode lodging rate and the field lodging rate,and the third internode lodging resistance index was negatively correlated with the field lodging rate,indicating that the third internode could replace the second internode to reflect the field lodging.4.There was a significant negative correlation between cellulose content/lignin content and lodging resistance index of basal internode,which may be the key index to determine lodging resistance of wheat.