Influence of temperature,solar radiation and precipitation on kernerel set and filling in rain-fed maize system in central China
【摘要】：[Introduction]Climatic factors have substantial effects on maize ear kernels number and kernel weight.In the previous studies,only a few climatic conditions for grain filling period have been covered,and few studies concerned about the quantitative relationship between grain filling parameters and all of the main climatic factors.The objectives of this study were to characterize and quantify the effects of climatic factors on kernel number,kernel weight and grain filling parameters.[Materials and methods]A 2-yr field experiments were conducted from March to November in 2012 and 2013 in the town of Huaqiao,Hubei Province,China.The treatments were arranged in a split-plot design with seasons as main plots and varieties as subplots.Three different seasons with two sowing date for each,spring maize(SPM,Marchl4 and 28 in 2012,and March18 and 26 in 2013),summer maize(SUM,May4 and 23 in 2012,and May 5 and 20 in 2013),and autumn maize(AUM,July 7 and 22 in 2012,and July 7 and 21 in 2013) were set as main-plot treatments.Three regional maize hybrid varieties varying in growth duration were designated as the subplots,including zhengdan 958(ZD958,93-120 d),denghai 9(DH9,95-128d),and yidan629(YD629,97-128 d).Daily meteorological data,were obtained.[Results]The growing degree days(GDD) and high temperature stress(killing degree days[KDD]) from V12 to silking always played significantly negative roles on ear ovules number(EON) and ear kernels number(EKN).EKN had significant and positive relationships with GDD,mean temperature(MT) and accumulated solar radiation(Ra) from silking to 30 days after silking(DAS).After pollination,KW and kernel filling rate during the linear kernel filling phase(KFR_(lgf)) exhibited significant negative relations with GDD,MT,KDD and Ra,whereas mean temperature difference(MAT)and accumulated precipitation(Pr) palyed significantly positive roles on KW and KFR_(lgf);The optimum MT for EON was lower than 22℃,while GDD and KDD should lower than 183.6℃d and 31.6 ℃d,respectively,from V12 to silking growth interval.But in order to obtained more EKN,GDD and KDD from V12 to silking need lower than 183.6℃d and 31.6 ℃d,respectively,and after pollination to 30 DAS,the optimum MT for EKN were 22 to 27.8 ℃,while GDD was250 to 368 ℃d and Ra was 200 to 339 MJ m~(-2).The optimum MT for KW were 23 to 27 ℃,with KDD lower than 44.3 ℃d,and Ra and Pr were 710 to 925 MJ m~(-2) and 50 to 216 mm,respectively.[Conclusion]Spring maize and SuM grown under optimal climatic conditions for EON and EKN setting,and then obtained more EON(20.7%and 9.6%) and EKN(32.1%and 18.5%) than AuM,However,SpM and SuM get lower KW(-12.5%and-17.5%) than AuM due to the higher MT and KDD after pollination.And so,grain yield for SpM significantly higher than SuM and AuM by20.0%and 23.9%,respectively.