Effect of Harvest Time on Total Sugar, Protein, Starch, and Fat Content in the Grains of Four Maize Varieties (Zea mays L.) Grown in Daloa, Côte d’Ivoire

Maize (Zea mays L.) is an important crop for food and feed, but determining an appropriate harvest date requires an understanding of changes in grain composition during maturation. This study assessed the influence of harvest timing on total sugars, starch, proteins and lipids in four maize varieties grown in Daloa, Côte d’Ivoire: F1Vn10, KABAMANOJ, LG336 and EV8728. The varieties were cultivated in a randomised-block field experiment and harvested on three successive occasions. The first harvest was conducted 110 days after sowing for KABAMANOJ, LG336 and EV8728 and 120 days after sowing for F1Vn10. Grain samples were analysed using the biochemical determination methods described in the manuscript, and treatment means were compared by analysis of variance followed by the Student–Newman–Keuls test at a 5% significance level. Across all four varieties, total sugar content was highest at the first harvest and declined by the third. EV8728 had a total sugar content of 370.70 µg/g fresh weight at the first harvest. Starch content generally increased with delayed harvesting, whereas protein and lipid contents also tended to be higher at the third harvest. The extent and statistical grouping of these changes differed among varieties and constituents. The findings indicate that harvest timing is associated with variation in grain biochemical composition under the study conditions. Selection of a harvest date should therefore reflect the biochemical constituent of interest rather than assuming a single optimum for all measured components.