Yang Lei^{1, 2}, Hafeez Noor^{1, 2}, Min Sun^{1, 2,}, Aixia Ren^{1, 2}, Pengcheng Ding^{1, 2}, Zhiqiang Gao^{1, 2}

In order to clarify the suitable planting density under wide-space sowing, conduct field experiments in Hongtong County Winter wheat demonstration base of Shanxi province from 2018 to 2020. The wheat variety Shannong-20’ was used as the experimental material, and five planting densities of 1.5 million plants·ha^-1 (D1), 2.25 million plants·ha^-1 (D2), 3.0 million plants·ha^-1 (D3), 3.75 million plants·ha^-1 (D4) and 4.5 million plants·ha^-1 (D5). The study aim to evaluate the influence of wheat density on population size, dry substance accumulation and remobilization, grain yield, protein, and starch. The results indicated that in the density range of 1.50-4.5 million plants·ha^-1, the population tiller number, population dry substance weight during sowing, wintering, anthesis, maturity stages, harvest index, dry substance production post anthesis, the rate of dry substance remobilization to grain, proportion to total dry matter of kernel weight in mature period, panicle number, grain yield, water utilization efficiency (WUE) throughout the growth period were highest in D4. The substance weight, dry matter transport before anthesis, remobilization rate, the rate of contribution about the vegetative organs post anthesis to grain in the overwintering-jointing were highest under D5. Compared with other treatments, the spike number, yield and WUE increased by 3.35%-33.42%, 2.40%-14.98% and 0.78%-10.87% in D4, respectively. The increase of planting density is profit for soluble sugar and sucrose content. Under different planting densities, there were significant or extremely significant correlations between yield and spike number, tiller number at over-wintering stage and jointing stage, dry matter accumulation before wintering stage and at different growth stages after jointing stage. The accumulation of dry matter in leaves and grains at maturity. Further path analysis showed that the most important factor affecting yield was tiller number, followed by dry matter accumulation. The 375×10⁴ plants·ha^-1 was the optimal planting density for constructing reasonable population structure of wheat, improving dry substance accumulation and transport, yield formation and the WUE.

winter wheat, planting density, population structure, dry matter accumulation transport, yield