Effect of Climatic Conditions Caused by Seasons on Maize Yield, Kernel Filling and Weight in Central China

In order to evaluate the effects of climatic conditions on maize grain yield (GY), kernel weight (KW), and kernel filling and identify the optimal climatic factors for GY and KW, 2-year field experiments in three seasons, i.e., spring (SPM), summer (SUM), and autumn (A(U)M), on maize were conducted in Central China. The results showed that SUM had more growing degree days (GDDs) than SPM and A(U)M due to the higher mean temperature (MT), and also resulted in higher temperature stress (killing degree days (KDDs)) in maize growth duration. Meanwhile, after silking, SPM and SUM had more GDDs and KDDs than A(U)M because of the higher MT, and the accumulated solar radiation (Ra) for SUM was significantly higher than for SPM and A(U)M. The GY of SPM was significantly higher than that of SUM and A(U)M, while SUM's GY was always the lowest, because the GDD GD, MT GD, and KDD GD played significantly negative roles on GY. The final KW for SUM was always the lowest, with GDD, MT, KDD, and Ra causing significantly negative effects, and M Delta T and precipitation having significant positive effects, resulting in a lower kernel filling rate during the linear kernel filling period (KFRlkf) and a lower GDD at the maximum kernel filling rate (GDD(KFRmax)). Maize KFRlkf has significant negative linear dependences on GDD, MT, and Ra. In summary, because of the higher MT, KDD, and GDD during maize growth and kernel filling duration negatively affecting the maize kernel filling rate, the GY and KW for SPM were the highest, and for SUM, they were the lowest; therefore, farmers should plant SPM first and then A(U)M in Central China.