Comparison Of Growth,Development And Maturity Of Different Maturity Maize Varieties In The First Accumulated Temperature Zone In Heilongjiang

Heilongjiang Province is an important maize growing area with high yield and potential in China.However,the contradiction between maize yield and grain moisture content in maize production area is widespread.Choosing maize varieties of high yield and low moisture content and suitable for local planting is the fundamental way to resolve this contradiction.To resolve the problem that grain moisture content is too high and maize maturity is poor at harvest in first accumulated temperature zone,we should choose maize varieties suitable for Heilongjiang Province.A field experiment was conducted to illustrate the difference maturity among the maize varieties at harvest and explore the law of growth and development in different maturing-type maize varieties.Experiments were conducted in the first accumulated temperature zone with late maturity varieties(‘XY 335',‘XX 2')and mid-late maturity varieties(‘SY 23',‘JD 27')as materials,which are large area planted,to compare and analysis the difference of them at harvest.The experiment is carried out from the aspects of organ moisture content,leaf senescence,grain filling and dehydration etc.The results of the study were as follows:(1)Grian moisture content of four cultivars was significantly positively correlated with the moisture content of stem,leaf,bract,pedicel and cob.The result of the path analysis on effect of the factors to grain moisture content showed that,cob>stem>leaf>bract>pedicel.The moisture content of each organ of mid-late maturity varieties were lower than that of late maturity varieties,and the grain moisture content in mid-late maturity varieties was lower than late maturity varieties by 18.47%~19.43%.(2)During leaf senescence,there are differences in different maturing-type maize varieties.Compared with the late maturity varieties,the mid-late maturity varieties had lower activities of SOD,POD,CAT and soluble protein content,higher MDA,higher leaf senescence,lower greenness and higher maturity in mid-late maturity varieties.(3)The grain filling characteristics of different maturing-type maize were different,midlate maturity were more quickly in launching of grain-filling and had the shorter grain filling duration.The grain milk line percentage in the mid-late maturity varieties was significantly greater than that of the late maturity varieties,the dry matter accumulation was faster,earlier in reaching the maximum grain weight and the dehydration rate is significantly faster than late maturity varieties.(4)The grain milk line percentage in the mid-late maturity varieties was significantly greater than that of the late maturity varieties and was higher maturity.Compared with the late maturity varieties,the mid-late maturity varieties had lower activity of grain enzyme.The content of IAA,GA and CTK in the mid-late maturity varieties was lower than that of late maturity varieties,the content of ABA was higher,then rapidly decreased,and the dry matter accumulation was faster.(5)There was no significant difference in yield,but significant in quality between different maturing-type maize,test weight and starch content of grains of mid-late maturity varieties were remarkably higher than that of late maturity varieties,the quality of mid-late maturity varieties was better.