Improving iron and zinc concentrations of grain in maize through breeding

摘要

Breeding staple crops with high micronutrient concentrations in grain has been proposed as a sustainable strategy for reducing mineral deficiencies in humans. Although maize lacks in some micronutrients, humans and animals can obtain at least part of their nutritional requirements from maize grain, particularly for iron (Fe) and zinc (Zn). Some breeding efforts were commenced to investigate possibilities of improving Fe and Zn concentrations in tropical maize, but the results are inconsistent. This study was conducted to ascertain prospects of maize breeding for simultaneous improvement of Fe and Zn concentrations in grain of 121 temperate maize genotypes with no yield reduction. Genetic material was set and grown in a two-year experiment in Eastern Croatia on a soil showing no Fe and Zn deficiencies. Micronutrient concentrations were determined by an ICP-OES (inductively coupled plasma optical emission spectrometry). Significant differences among genotypes were found for both micronutrient concentrations as well as yield. The grain concentration ranges were 11.0 - 40.7 for Fe and 13.4 - 33.2 for Zn (in mg/kg dry weight). Only weak genotype x environment interaction was detected. Correlation coefficient between Fe and Zn concentrations was highly significant (r=0.70), while the associations between Fe and yield as well as Zn and yield were very weak and weak: r=-0.12 and r=-0.27, respectively. Our results suggest that simultaneous improvement of Fe and Zn concentration in grain of temperate maize is feasible with no substantial yield decrease. Potential breeding strategies for micronutrient improvement including aspects such as genotype' x environment interaction, choice of germplasm and breeding methods will be discussed.