Calcium Application Synergistically Enhances Yield and Nutritional Quality in Waxy maize

Abstract

Optimizing the yield and nutritional value of waxy maize is crucial to meet evolving consumer demands and ensure food security. This study investigated the effects of foliar -applied calcium chloride (CaCl₂, 18 mmol/L, applied at the V12 stage) on 36 hybrid varieties of waxy maize. The treatment slightly suppressed plant and ear height, but significantly increased ear length, ear diameter, and fresh weight per ear. Photosynthetic analysis revealed that 34 out of 36 hybrids exhibited a significant increase in net photosynthetic rate (ranging from 4.5% to 230%), while two showed a non-significant increase. SPAD values non-significant increase suggesting that calcium enhanced the operational efficiency of the photosynthetic apparatus rather than chlorophyll content. Concurrently, the treatment significantly enhanced kernel nutritional quality. Soluble sugar content increased by 1.1–17%, crude protein content by 1.5–24.8%, and key micronutrients—zinc (2.7–13.8%), iron (1.7–15.4%), calcium (1.6–15.3%)—were significantly elevated. Correlation analysis revealed that soluble sugar content was highly significantly positively correlated with ear length and diameter, and that increases in soluble sugar and protein were significantly associated with micronutrient accumulation. These findings indicate that exogenous CaCl₂ optimizes source–sink balance by improving photosynthetic efficiency and assimilate partitioning, thereby driving a synergistic enhancement of yield and nutritional quality in waxy maize. This work provides a physiological basis and a practical strategy for the targeted improvement of maize quality.