Research In The Dehydration Characteristics Of Ear Shape And Properties Of 11 Maize Hybrids

Mechanical harvesting is a bottleneck in realizing the whole process mechanization of corn production in China^[1],and realizing the direct harvest of grains is the current and future development trend of corn mechanical harvesting.In order to increase China’s corn yield and ensure the basic food demand,the promotion and popularization of Corn Varieties in China in the past mainly focused on high yield,while the mechanical grain harvest also needs to consider the characteristics of corn grain in many aspects,such as water content,damage rate and so on.In order to promote the popularization and development of maize mechanized grain harvesting technology in the central region of Jilin Province,9 Maize Varieties（Zhengdan 958,Xianyu 335,Jidan 27,Xiangyu 998,Tianyu 108,Ruipu 909,Dade 216,Heyu 187 and Fumin 985）which have been popularized in Jilin Province in recent years and 2 maize varieties newly bred by our team（Jinongda 607 and Jinongda 6018）were selected as experimental materials for mechanized grain harvesting test,It is expected to screen out maize varieties suitable for mechanized grain harvest,which are suitable for planting and popularization in the central region of Jilin Province.This study mainly studied the dehydration characteristics of ear traits of 11 maize varieties,analyzed the grain moisture content and dehydration rate in different periods,and clarified the relationship between grain moisture content,dehydration rate and bract traits,grain traits,grain type and yield traits.The research results are summarized as follows:1.The grain moisture content of 11 Maize Varieties in different sampling periods is different,and the grain moisture content of different varieties in the same sampling period is also different,which is mainly determined by the genotypes of different varieties.From the perspective of grain moisture content at harvest,6 of the 11 maize varieties meet the mechanical grain harvest standard.They are Jidan 27,Jinongda 6018,Dade 216,Xianyu 335,Jinongda 607and Ruipu 909 respectively.2.The dehydration rate of different varieties is also different.The grain dehydration rate of four middle and early maturing varieties（Jidan 27,Heyu 187,Dade 216 and Jinongda 6018）was similar,and the dehydration rate was faster from 30d to 45d after pollination.Among the three medium maturity varieties,the grain dehydration rates of Jinongda 607and Xiangyu 998 are similar,the dehydration rate is faster from 35d to 45d after pollination,and the grain dehydration rate decreases gradually after physiological maturity.The dehydration rate of medium mature Xianyu 335 and late mature Ruipu 909 was faster 30-40 days after pollination,the grain dehydration rate decreased after physiological maturity,and gradually increased 10 days before harvest.The grain dehydration rate of Fumin 985 and Zhengdan 958 at late maturity was faster from 35d to 45d after pollination,and gradually decreased after physiological maturity.3.There was a significant positive correlation between bract length and grain moisture content at harvest,and the correlation coefficient was r=0.6593.There was a very significant positive correlation between the number of bract layers and grain moisture content at harvest,and the correlation coefficient was r=0.9040.There was a positive correlation between bract thickness and grain moisture content at harvest,but the correlation was not significant.4.The axial diameter,the number of rows per panicle and the grain moisture content at harvest stage reached a very significant positive correlation,and the correlation coefficients were r=0.8459 and R=0.7956,respectively.There was a correlation between panicle length,grain number per row and grain moisture content at harvest,but it was not significant.The analysis of panicle traits and the average dehydration rate before and after grain physiological maturity showed that there was no significant correlation between the dehydration rate before grain physiological maturity and panicle traits.After physiological maturity,the dehydration rate had a significant negative correlation with shaft diameter and the number of rows per panicle,and the correlation coefficients were r=-0.7335 and R=-0.7826 respectively.The dehydration rate had a positive correlation with panicle length and a negative correlation with the number of grains per row,but the correlation was not significant.There was a significant negative correlation between grain length and grain dehydration rate,and the correlation coefficient was r=-0.6214.Grain width and thickness were negatively correlated with grain moisture content and dehydration rate,but the correlation was not significant.5.Through the simulated mechanical harvest experiment,it is found that when the grain moisture content is 19%-25%,the grain crushing rate is low.6.From the perspective of dehydration characteristics of panicle characters,grain crushing rate and yield,the varieties suitable for mechanical grain harvest are Ruipu 909,Jinongda 607and Jinongda 6018.