Xenia and Deficit Nitrogen Influence the Iron and Zinc Concentration in the Grains of Hybrid Maize

Xenia is the immediate effect of pollen on seed development after pollination. This study was conducted to investigate xenia’s effects on Fe and Zn concentration in self- and open-pollinated maize seeds. Eighteen maize hybrids derived from parents with varying concentrations of Fe and Zn were planted at Potchefstroom, Cedara and Vaalharts in South Africa for two seasons, 2017 and 2018. Open- and self-pollinated seeds were compared. Self-pollination of five selected healthy maize hybrids of uniform height from each plot was performed. Fe, Zn and phytic acid (Pa) analysis was conducted on self -and open-pollinated maize seeds, and the molar ratios of Fe and Zn to Pa were also calculated to assess the bioavailability of Fe and Zn. The ranges of Fe, Zn and Pa, and the molar ratios of Fe and Zn to Pa in self-pollinated maize seeds were 15.93–21.36 mg kg−1, 18.50–24.34 mg kg−1, 4.63–5.84 mg g−1, 21.97–31.22 and 23.53–30.16 under high N, and 12.76–19.29 mg kg−1, 16.78–23.50 mg kg−1, 5.05–6.48 mg g−1, 26.12–44.54 and 25.44–35.94 under low N conditions, respectively. The ranges of Fe, Zn and Pa, and the molar ratios of Fe and Zn to Pa in open-pollinated seeds were 14.34–19.12 mg kg−1, 17.27–23.27 mg kg−1, 4.96–5.89 mg g−1, 20.90–28.22 and 22.92–29.37 under high N, and 12.54–18.39 mg kg−1, 16.94–20.93 mg kg−1, 5.30–6.17 mg g−1, 27.90–38.75 and 27.95–36.34 under low N conditions, respectively. The bioavailability of Fe and Zn was high in self-pollinated seeds under high N conditions, while Fe was higher in self-pollinated seeds, and Zn was higher in open-pollinated seeds under low N conditions. Combined over seasons, there were no significant differences between the values of Fe and Zn in self- and open-pollinated seeds under both high N and low N conditions. This indicated that unknown males had no influence on Fe and Zn concentration in maize. Therefore, either self- or open-pollinated seeds can be used for Fe and Zn determination in maize crosses.