Special hard endosperm maize (Zea mays L.) adapted for optimum dry milling yields is produced worldwide. Argentine flint maize is internationally known, and specific values for grain vitreousness, floaters, and test weight are demanded by the industry. Agricultural practices aimed to reach these standards, however, are not clear for farmers. Our general objective was to identify possible management options for maximizing the grain quality attributes described by these standards. We tested two flint and two dent kernel type genotypes under contrasting management options and environmental conditions (stand density, N fertilizer, defoliations, years), and studied their yield and grain quality response. Flint genotypes yielded less than dents across all tested field treatments (flint vs. dent, P ≤ 0.001), with larger differences at the lowest yielding conditions. Large differences between kernel types, and for genotypes within each kernel type, were evident for all grain quality traits (test weight, floaters, vitreousness, 8 mm screen retention) and composition (protein, oil, starch). Low N fertilization levels and stressful situations during grain filling where the treatments reducing grain hardness and screen retention the most, especially for some genotypes. Other than genotype selection, adequate N availability and low stand density helped improve test weight, vitreousness, floaters, and screen retention, all traits relevant for maize dry milling industry.Core Ideas Crop management options for maximizing maize kernel hardness are mostly unknown. Flint genotypes always yielded less than dented ones across a wide range of field treatment combinations. Stand density, N fertilization, and genotype selection are key management options for optimum grain quality.

Maize (Zea mays L.) kernel hardness is of utmost importance for dry‐milling processors. Zeins, maize prolamins, are known to be key proteins affecting this trait. We investigated the response of kernel zein profiles to N fertilization in maize hybrids with contrasting kernel hardness (measured as test weight, vitreousness, kernel density, and floaters percentage). A field experiment was done during two seasons, with three N fertilization treatments and four commercial hybrids with different hardness (two flint and two dent kernel types). We also measured yield, kernel protein concentration, and zein profiles (Z2, or γ and β, and Z1, or α and δ). Flint kernel type always yielded less and showed higher kernel hardness indicators when compared with dents (P < 0.01). N fertilization helped increase yield and kernel hardness in both kernel types. Flint kernel type had consistently more Z2 than dents, while only in 1 yr Z1 was higher in flints. Dent kernel type had a Z1/Z2 ratio similar to or higher than flints. Increasing N resulted in increased concentration of both zein types, but the effect was more pronounced on Z1. Significant correlations were observed between the different zein types (Z1 and Z2) and hardness indicators and total protein concentration, but Z2 showed the highest correlations with all kernel hardness traits. Our results expand previous knowledge on genotype and N fertilization effects over zein profiles and their involvement in kernel physical characteristics relevant for dry milling.