Multiyear evaluation of agronomic traits, nutritional quality, macro and microelement profiles of white maize genotypes (Zea mays L.) under Black Sea conditions

Abstract

White maize (Zea mays L.) is increasingly valued for diversified food uses, yet agronomic performance and nutritional quality can fluctuate markedly across humid temperate seasons. This study evaluated 14 white maize testcross genotypes, including the commercial check P2948W, across five consecutive field seasons (2020-2024) in the Black Sea Region of Türkiye. Phenology and plant architecture, grain yield (t ha-1), major compositional traits (protein, oil, starch, cellulose and ash), and macro- and microelement concentrations (Ca, Mg, K, P, Fe, Zn, Cu and Mn) were assessed using near-infrared spectroscopy (NIRS) and standard field protocols. Data were analyzed using linear mixed-effects models to partition genotype, year, and genotype x year effects, followed by multivariate visualization (genotype x trait, GT, biplot) and stability assessment using AMMI and GGE biplot approaches (with years treated as environments). Grain yield showed wide genotypic variation (7.23-11.43 t ha-1), with P2948W ranking highest and TTBYM2019–37 lowest on the across-year mean basis, whereas pollen shedding occurred within a narrower window (73.7-78.1 days after planting). In contrast, most compositional traits and mineral means exhibited limited genotypic separation in the combined analysis, indicating strong seasonal influence on quality and mineral expression. Overall, the combined mixed-model and stability framework supports evidence-based selection of high-biomass, broadly adapted white maize candidates for regional cultivar development and provides a transparent basis for multi-year evaluation of quality and mineral attributes.