Responses of yield traits and grain filling characteristics of maize to sowing dates and their relationships with meteorological factors

This study discussed the influence of sowing dates on maize yield. Under the condition of limited water irrigation, the effects of different sowing dates on yield, yield traits, and grain-filling characteristics of maize of one crop cultivation per year, and the correlation of meteorological factors with yield, yield traits, and grain-filling parameters of maize were studied to provide data-based support for high yield and high-efficiency production in low-plain areas. ‘Xianyu 335’ and ‘Zhengdan 958’ were used in the experiment. Five sowing dates were set: May 5 (SD₁), May 20 (SD₂), June 5 (SD₃), June 20 (SD₄), and June 30 (SD₅). The results showed that: 1) the sowing date had a significant effect on maize yield, which was affected by variety and climate. The grain yield increased initially, followed by a subsequent decrease with the extension of sowing dates. The two-year average yield of SD₁ was the lowest, and that of SD₄ was the highest. The difference in yield between SD₃ and SD₄ was not significant. The high yield of SD₄ was mainly due to the high grain number per spike and the 100-grain weight. 2) Path analysis showed that the contribution of yield factors to yield affected each other, and the most direct effect on yield was 100-grain weight. 3) For the variation characteristics of grain weight described by the Logistic model, the determination coefficient, R², was above 0.98, and the difference was significant at P<0.01. The grain weight was determined by the average grain-filling rate (V) and grain-filling duration (D), and D had the largest direct contribution to the grain weight. 4) From the effect of meteorological factors on yield and yield components, the higher the daily average temperature from sowing to silking and the larger the daily temperature difference (TR_Avfm) from silking to maturity, the higher the yield. The more days that had temperatures ≥35 ℃ (D1_fa) after 10 days of silking, the higher the daily average temperature (T_Avfm) from silking to maturity, and the lower the yield and 100-grain weight. T_Avfm had the largest direct contribution to the yield and 100-grain weight, and the effects of various meteorological factors on the yield and grain weight were mutually affected. The main reason for the lower grain weight of SD₁ was that the accumulated temperature of ≥10 ℃ during the whole growth period and the accumulated temperature of ≥10 ℃ from sowing to silking were higher, T_Avfm was higher, TR_Avfm was smaller, the days of D1_fa were higher, and D was shorter. SD₃ and SD₄ had larger TR_Avfm, higher V and D values, and higher grain weights. Although the sowing date of SD₅ was relatively late, the lower T_Avfm resulted in a decrease in the accumulated temperature from silking to maturity, and the filling stage was shortened, thereby reducing the final grain weight. 5) In terms of varieties, the main reasons for the higher yield of ‘Xianyu 335’ compared with ‘Zhengdan 958’ were the higher grain number per spike and 100-grain weight, and the product of V and V×D of ‘Xianyu 335’ were 0.19 mg·grain⁻¹ and 0.73 mg·grain⁻¹ higher than those of ‘Zhengdan 958’, respectively. This showed that selecting varieties with high yield potential and a high filling rate and sowing from early June to middle and late June could optimize meteorological factors during the growth period, thereby increasing grain weight and yield.