Response of grain quality to plant growth dynamics in summer maize as influenced by sowing dates and weather factors

The growth and development of maize are related to the accumulation of carbon and nitrogen and the absorption and transportation of nutrients within the plant, ultimately affecting grain quality. This study utilized data from the summer maize field experiments conducted at Gucheng station (2018–2021) and Suzhou station (2019–2021) in the Huang-Huai-Hai Plain, China. Seeds were sown at conventional sowing date (S2), 10 days before S2 (S1), 10 days after S2 (S3), and 20 days after S2 (S4). Based on the path model and stepwise multiple regression analysis, the response relationship between maize grain quality and plant growth and development dynamics was clarified across varying sowing dates, and combined with the influence of meteorological factors under varying sowing dates, the correlation between meteorological factors, maize growth and development and final grain quality was understood. The results showed as follows: (1) A significant positive correlation was identified between kernel protein content and leaf area index (LAI) ( r 2 = 0.36); Increase in LAI and above-ground biomass (AGB) during the sowing-jointing stage positively affected grain starch content ( r 2 = 0.44). An increase in LAI during this stage also promoted grain oil content ( r 2 = 0.27). Additionally, AGB had a significant effect on grain cellulose content prior to grain filling ( r 2 = 0.64), promoting it before jointing stage and inhibiting it afterward. (2) Above-ground biomass during the sowing-jointing and tasseling-grain-filling stage coupled with growth period duration (GPD) from sowing to jointing, were key contributors to grain protein yield ( r 2 = 0.60). Similar growth factors were pivotal for enhancing both grain starch and oil yields. In contrast, grain cellulose yield was uniquely influenced by AGB during the sowing-jointing stage ( r 2 = 0.55). (3) Generally, LAI at the sowing-jointing stage was a key co-promoting factor for grain protein, oil, and starch contents. Above-ground biomass during the sowing-jointing stage was a common response factor for grain cellulose content and yield. Grain protein, oil, and starch yields were significantly positively correlated with GPD at the sowing-jointing stage and AGB at the tasseling-grain-filling stage. The criticality of sowing-jointing stage was related to the significant difference of heat and radiation resources under different sowing dates in the study. The study also indicated that the grain quality could be improved by appropriately advancing the sowing date and extending the sowing-jointing duration. • Leaf area index at the sowing-jointing stage had a positive correlation with grain quality content. • Grain quality could be improved by advancing the sowing date. • Extending the sowing-jointing duration appropriately was beneficial to grain quality yield. • The importance of sowing-jointing stage was related to the difference of meteorological factors.