Abstract:

To explore the optimal sowing date and rate configuration for achieving high and stable yield of winter wheat, a field experiment was conducted using the main cultivar ‘Shannong 40’ with five sowing dates (October 6, 12, 18, 24, and 30, designated B1-B5) and three sowing rates. Regression analysis and analysis of variance (ANOVA) were used to investigate the effects of sowing date and rate on the developmental process, agronomic traits, yield components, and grain yield of winter wheat. The results showed that: (1) delaying the sowing date significantly shortened the pre-winter growth period and reduced the plant height of wheat seedlings, with tiller number decreasing by 1.4 per 6 days. Population size and grain yield initially increased and then decreased with delayed sowing. As sowing rate decreased, spike number and grain yield generally showed a decreasing trend, while tiller number and plant height at the late growth stage showed an increasing trend. (2) Sowing date and rate significantly affected spike number, grain number per spike (GNPS), and grain yield (P<0.05). (3) Significant differences (P<0.05) were observed among different sowing dates for spike number; between B5 and B1-B4, and between B4 and B1 for GNPS; between B5 and B1-B4 for thousand-grain weight; and between B5 and B1-B4, and between B4-B3 and B1-B2 for grain yield. Additionally, significant differences (P<0.05) in spike number, GNPS and grain yield were found between low sowing rate and the other two rates (high and optimal). Based on these results, the suitable sowing date for winter wheat in northwestern Shandong is Oct. 6-24, and the appropriate basic seedling stand for ‘Shannong 40’ is 225×10⁴-270×10⁴ plants/hm². Within this sowing window, moderately increasing the sowing rate helps achieve high and stable yields in winter wheat.

Key words: winter wheat, sowing date, sowing rate, phenophase, yield components, grain yield