Genotypic Variability of Micronutrient Element Concentrations in Maize Kernels

Abstract

Micronutrient malnutrition afflicting globally over two billion people can be reduced by improving major staple food crops through traditional plant breeding. This study was conducted to ascertain genotypic variability and prospects of maize breeding for higher concentrations of boron (B), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), and zinc (Zn) in grain among 121 genotypes. Genetic material was set and grown in a field trial in Eastern Croatia in 1998 and 1999. Micronutrient contents were determined by an ICPOES (inductively coupled plasma optical emission spectrometry). Significant differences among genotypes were found for all micronutrient concentrations using analyses of variance. The grain concentration ranges were 0.5–6.1 (B), 0.5–3.4 (Cu), 11.0–60.7 (Fe), 4.7–14.8 (Mn), 0.1–1.0 (Ni), and 11.9–33.2 (Zn) (all in mg/kg dry weight). The greatest repeatability estimates were obtained for Cu (85.1% and 83.3%), Mn content (58.2% and 73.0%), and Zn content (48.2% and 50.9%) in 1998 and 1999, respectively. Combined over two years, significant differences among genotypes as well as between years were found for all micronutrients investigated, except for Ni status. Highly significant (at P>0.01) interaction year x genotype was detected only for Cu and Ni content. The highest heritability estimates were found for Cu, Mn and Zn content. Our results suggest that improving micronutrient content in maize genotypes appears to be the most reliable for Mn and Zn content due to high repeatability and heritability estimates and parameter stability across environments. Moreover, there were no tight negative associations between micronutrient contents in grain and grain yield indicating a possibility to combine micronutrient-rich traits with high yield.