Study On The Characteristics Of Grain Filling And Dehydration Of Maize Inbred Lines And Their Hybrids With Different Maturities

The maize grain yield is mainly limited by the dry matter accumulation of kernels.The grain filling process directly affects the accumulation of dry matter in the maize grain and plays a decisive role in the grain yield.It is necessary that study maize grain filling process to maize yield.With the rapid development of urbanization,full mechanization of maize production has become inevitable.The Maize mechanized harvesting is an important part of the mechanization of maize production.It is required that the water content of maize kernels at the time of harvesting is relatively low.In the northeast region,mid-late and late-maturing varieties are generally planted and are not suitable for mechanization.It is of great significance to study the dehydration characteristics of maize grain for the selection of suitable varieties for mechanized harvesting.In this study,experiment selected 11 varieties of maize inbred lines with different ripening stages and 30 hybrid varieties,and studied their grain filling and dehydration characteristics.The results of the study are as followings.1.About grouting characteristics of maize inbred lines and their hybrids(1)The corn grain filling process showed a slow-fast-slow trend,and the grain filling rate showed a single-peak curve change.The late stage lasts longest.The increase of grain weight in the early stage was the largest,and the filling rate showed the early stage > the middle stage > the late stage.The early-maturing and the middle early-maturing types of inbred lines and hybrids have large filling rates at the early filling stage,and the late-maturing types have a large filling rate at the late filling stage.(2)The early-maturing and middle early-maturing type inbred lines reached the earliest peak of grain filling,and the initial grain-filling was large.Among the 11 inbred lines,Zheng 58 and J 187 were characterized by large grain filling rate,active period of M5972 grain filling,and long filling period.The quality of 100 grains of Zheng 58?J187?M5972 was higher.(3)The early maturity and mid-early maturity types of hybrids reached the earliest time of maximum filling rate,and the initial grain-filling and maximum filling rate were relatively large.2.Research on dehydration characteristics of maize inbred lines and their hybrids(1)The grain water content of early maturing inbred lines decreased rapidly at 20 days after pollination,and tended to be gentle after pollination of 40 days.The water content of kernels of medium-maturing,middle-late-maturing and late-maturing types continued to decrease at 20 days after pollination,among which,the medium maturity type had the fastest decline.(2)The grain water content of early maturing hybrids decreased rapidly after 20 days from pollination and stabilized after 50 days.The water content of the medium-early maturity type decreased rapidly from 25 days to 40 days after pollination,decreased slowly after 40 days,and tended to be stable after 60 days.The water content of medium-mature and late-maturing types decreased rapidly after 15 days of pollination,and decreased continuously after 35 days.The grain water content of late maturity type in the late fall 15 d after pollination fast,slow decline after 40 d.(3)The grain dehydration rate in early maturing type inbred lines was higher 15 days to 40 days after pollination.In the medium-early maturity type,the dehydration rate was higher at 20d-35 d after pollination.The dehydration rate of medium maturity type was higher at 15d-25 d after pollination.The dehydration rate of the medium-late-maturing type was higher 15 days to 30 days after pollination.The dehydration rate of the late maturity type was higher 15 days to 30 days after pollination.(4)The rate of grain dehydration in early maturing hybrids was highest from 20 d to 25 d after pollination.For the medium-early maturity type,the dehydration rate was higher at 15 d to 30 d and 40 d after pollination;The dehydration rate of medium maturity type was higher from 15 d to 35 d after pollination.The late-maturing and late-maturing types had higher dehydration rates 15-35 days after pollination.3.Studying the combining ability and relevance of important traits related to grain filling and dehydration characteristics.(1)Inbred line Zheng 58,PH6 WC middle stage duration period(T2),middle stage average velocity(V2)and 100 grain quality(A)have a high positive effect of general combining ability.KW5G321 middle stage average velocity has a high positive effect of general combining ability.The combination of PH6WC×PH4CV,PH6WC×Chang 7-2,and KWCB1×KWS49 had higher specific combining ability of 100 grain quality.(2)The general combining ability positive effect of the dehydration rate of KW5G321 is the highest,and the negative effect of the general combining ability of the grain water content is the highest.(3)The correlation analysis showed that the grain filling rate,dehydration rate,and grain water content of the inbred lines were significantly positively correlated with each other.The dehydration rate of the hybrid seed grain was significantly positively correlated with the grain water content.