A soil tillage system adjusted to the soil type and agro-ecological conditions, together with the optimal nutrient supply, is a prerequisite for high maize (Zea mays L.) yield. However, there is little knowledge about the influence of soil tillage and nitrogen (N) rates on maize grain quality. A study was initiated in 1978 in Zemun Polje, Belgrade, Serbia, on the chernozem soil type. The effects of three N rates—0, 180 and 240 kg N ha−1—within three tillage practices—no-tillage, reduced and conventional tillage—and their influence on grain yield (GY) and the content of proteins, starch, oil, total tocopherols and carotenoids, phytic phosphorus (Phy), glutathione (GSH), phenols and inorganic P (Pi) in maize grain were analysed in the period 2016–2018. Differences in maize GY were 2.57 and 3.01 t ha−1 for reduced- or no-tillage, respectively, in comparison to conventional tillage. Conventional tillage and higher N rates contributed to the increase in maize yield and the grain nutritional quality with regard to the increased level of proteins, GSH and Phy. On the other hand reduced inputs were beneficial only for grain quality, in relation to the increase in tocopherols and phenols.

Breeding program aimed at converting standard maize inbred lines to their quality protein maize (QPM) counterparts for growing in temperate climate is being conducted at Maize Research Institute (MRI). The objective of the research presented herein was to develop QPM versions of two commercial ZP inbreds through marker assisted selection (MAS) with opaque2 specific molecular markers, while maintaining their good agronomic performances and combining abilities. Donor line was a tropical QPM line CML 144. After two backcross and three selfing generations, six near isogenic lines (NILs) with 93% recovery of the recurrent parent genome were created from one cross. Average increments of 30% in tryptophan content and 36% in quality index were obtained, as well as kernels with less than 25% opaque endosperm. Grain yield was increased by 11–31% and combining abilities of the improved lines were on a par with the original line. Correlations between biochemical and agronomic parameters revealed that selection for plant height, ear length and kernel row number together with tryptophan content could be recommended for development of QPM with this material. However, several impediments emerged during selection. Major drawbacks in NIL development were small number of opaque2 recessive homozygotes (4.5% and 7.6% in BC2F2 of two crosses) and poor seed set throughout selection, which led to the loss of one cross. Moreover, in the other cross many plants in different generations had to be omitted from further selection due to the insufficient number of kernels. This phenomenon could be explained by incompatibility between pollen and style, possibly due to the exotic donor germplasm. Overall, it could be expected that the use of NILs, which are adapted to temperate climate and have high percentage of domestic germplasm, would outbalance the noted impediments and increase MAS efficiency in different breeding programs.

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.

No abstract

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.