Intensive weed management is required to meet the growing demands of sweet maize production. Herbicide application is inevitable in sweet maize production, while foliar fertilizer is commonly used in cropping in order to improve crop yield and quality. The effect of nicosulfuron and mesotrione, with and without foliar fertilizer, on the content of phytochemicals (i.e. carotenoids, tocopherols and free phenolic acids) in the kernels of three sweet maize hybrids was evaluated. Herbicides applied alone mainly improved the nutritive profile of the sweet maize kernel. The application of herbicides in combination with foliar fertilizer showed a high variability in the concentration of carotenoids, tocopherols and free phenolic acids. The significant change in the content of phytochemicals was induced by the applied treatments, but it is also genotype-dependent, which was also confirmed by the Principal Component Analysis.

The chemical method of weed control is an indispensable step in cropping practices of sweet maize. Application of the herbicides can induce the abiotic stress which affects the non-enzymatic antioxidants in the crops, especially on the sensitive one, like sweet maize is. Antioxidant profile, through the measurement of the soluble phenolic, carotenoids, phytic acid and glutathione concentration, in the grain of the three sweet maize hybrids after application of herbicides, foliar fertilizer, as well as their combinations, in field experiment, conducted over a two-year period, was determined. The content of tested antioxidant parameters was dependent on hybrids, growing season, as well as of the applied treatment. Sulfonylurea herbicides significantly increased the antioxidant status of sweet maize fresh grain, compared to the herbicide from triketone group, without affecting the fresh grain yield. Combination of herbicide plus foliar fertilizer expressed a various impact on antioxidant profile of the maize grain. Furthermore, significant correlations (positive and negative) between fresh grain yield and analyzed antioxidants in grain of three sweet maize hybrids were noticed.

Development of micronutrienten riched staple plant foods through plant breeding holds promise for sustainable and cost-effective food-based solutions to combat micronutrient deficiencies. The first step in this process is screening aviable germplasm for micronutritient content, so the aim of this study was determination of carotenoids and tocopherols content in set of maize inbred lines. Carotenoids (lutein, zeaxanthin and β-carotene) and tocopherols (α, β+γ and δ) content in 101 maize inbred lines with different kernel type (37 orange, 29 yellow, 4 white,19 sweetcorn and 12 popcorn) were determined by HPLC-DAD. The mean values of L+Z, β-carotene, α-tocopherol, β+γ tocopherol, and δ-tocopherol, were 31.34, 8.72, 10.22, 49.17 and 1.81 μg/ g, respectively. Content of α -tocopherol was in the range from 2.22 to 38.14 μg/g and β+γ tocopherols from 12.10 to 105.52 μg/g, β-carotene 1.20 to 39.37 μg/g and lutein+zeaxanthin 11.28 to 69.31 μg/g. White maize lacked carotenoids in the endosperm due to the presence of recessive genes. The highest value of β-carotene had inbred line H, L+Z inbred W-4, γ-tocopherols KRW 803-3-1-2-1 and α –tocopherol P21. Orange kernel inbred lines had the highest value of L+Z and β-carotene, yellow kernel inbred lines α –tocopherol, whereas sweetcorn inbreds had the highest value of γ-tocopherols. The genetic background undoubtedly influences chemical quality and line with high content of particularly micronutritients may be used in breeding program to improve nutritional value.

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Among cereals, maize has the highest content of bioavailable micronutrients in grain, particularly β-carotene and α-tocopherol, which makes this crop the most appropriate for biofortification. Great genetic variability is a valuable source of micronutrients, and genotypes with enhanced grain content could be used for improvement of commercial hybrids or synthetic populations creation. Three populations with dark orange, dark red and red grain, five elite lines, and their crosses were evaluated for β-carotene and α-tocopherol content. Based on obtained results, line (L5) could be further used in breeding for increased β-carotene content, and population with dark orange grain (P1) is recommended as a good source for multi-nutrient biofortification for both β-carotene and α-tocopherol. Three lines (L1, L2 and L5) had significantly higher value of α-tocopherol in crosses with dark red population (P2), compared to lines per se, and require several cycles of back-crossing for increase nutrient content.