Wheat Growth And Grain Yield Responses To Sowing Date-Associated Variations In Weather Conditions

Variations in weather conditions can affect winter wheat (Triticum aestivum L.) yield. This study aimed to determine the ways in which the yield formation processes of winter wheat respond to variations in weather conditions at a large range. Five sowing dates (SDs) were set at 15-d intervals from early October to early December during the period 2015-2017 in the North China Plain (NCP). Sowing in mid-October (SD2) produced the highest yield, which was similar to that of conventional sowing (early October, SD1). Sowing in early December (SD5) increased wheat yields by 6.1 and 14.0% averaged two year compared to sowing in early (SD3) or late (SD4) November, respectively. The increased yield for SD5 was attributed to increased dry matter accumulation (DMA) pre-anthesis, and greater numbers of spikes and kernels. The DMA, spike number, and kernel number were mainly influenced by the pre-anthesis plant growth rate (PGR), which was affected by temperature from sowing to anthesis. Low temperatures (maximum temperature <18.9C, minimum temperature <7.6C, daily mean temperature <12.8C) from sowing to anthesis occurred following SD3 and SD4 sowings, which decreased pre-anthesis PGR, and in turn decreased the pre-anthesis DMA and spike and kernel number. These eventually reducing the total biomass and grain yield. We conclude that sowing wheat extremely late (early December) has the potential to increase grain yield, which may offset the negative effects of climatic factors in the NCP.