不同播期玉米籽粒灌浆特性及其与气象因子的关系

Relationship between grain filling characteristics of maize and meteorological factors under different sowing dates

为探讨吐丝后玉米百粒重和籽粒灌浆参数与气象因子之间的关系,为成都平原区玉米适期播种及高产高效栽培提供参考依据,本研究以广适玉米品种‘仲玉3号’为供试材料,设置6个播期处理(3月27日、4月6日、4月16日、4月26日、5月6日、5月16日),研究不同播期下籽粒干物质积累及灌浆特性。结果表明:随播期推迟,玉米生育时期缩短,籽粒产量和百粒重显著降低;产量下降主要由粒重引起,而引起粒重降低的原因主要与灌浆速率和灌浆速率达最大值的粒重有关,而灌浆速率和灌浆速率达最大值的粒重受吐丝后有效积温、日平均温度和降雨量的显著影响。在试验范围内,籽粒灌浆速率、灌浆速率达最大值的粒重和最终百粒重随日平均温度的升高而增高,随有效积温的增加呈增大的趋势。延迟播种,因玉米灌浆期大量降雨引起灌浆速率降低,粒重减小;积温是影响籽粒灌浆和百粒重的主要气象因子,适时早播玉米生育时期相对延长,吐丝后有效积温增多有利于籽粒灌浆。在当地气候条件下,4月6日播种吐丝后有效积温达863.36℃时,灌浆性能较好,可获得较高的粒重和产量。生产上应根据不同种植制度选择适宜的播种日期,春播应尽量安排在3月底至4月初播种,对于需要晚播的区域,应考虑与前茬作物的关系,争取在5月上旬完成播种,避免后期气象因子异常对籽粒灌浆造成不利的影响。

This study,conducted to provide a theoretical basis for suitable sowing dates for the high yield and high-efficiency cultiva-tion of maize in the Chengdu Plain,explored the relationships between 100-kernel weight(KW),grain filling parameters,and sowing date-associated meteorological factors after silking.To investigate the dry matter accumulation and grain filling characteristics under different sowing dates,the widely adaptive maize cultivar‘Zhongyu 3’was sown on six dates(March 27,April 6,April 16,April 26,May 6,and May 16).The results showed that with delayed sowing dates,the growth period of maize decreased,and grain yield and KW decreased significantly.The decreased yield was mainly attributed to KW,and variations in the grain-filling rate(Gmean)and the kernel weight at the maximum grain-filling rate(Wmax)were the primary factors that influenced KW.Both Gmean and Wmax were markedly affected by the effective accumulated temperature(AT),daily average temperature(MT),and precipitation(Pr)after silking.In this experiment,Gmean,Wmax,and final KW increased along with MT and AT.A large amount of precipitation occurred during the grain filling period owing to the delayed sowing dates resulted in a decrease in Gmean and KW.AT was the major factor influencing grain-filling characteristics and KW,and a relatively prolonged growth period under early sowing conditions contributed to the in-creased effective accumulated temperature after silking,which was beneficial for grain filling.With sowing on April 6,higher KW and maize yield were obtained with better grain-filling performance when the effective accumulated temperature reached 863.36°C.We concluded that suitable sowing dates should be established for the different planting systems used in maize cultivation.Spring maize should be sown as early as possible in the plain regions of the Sichuan Basin from the end of March to the beginning of April.The relationship with the previous crop should be considered in summer sowing especially for areas where late sowing is unavoid-able,with sowing being completed in early May to avoid the adverse effects of abnormal meteorological factors on grain filling.