Environmental and genetic effects on cadmium accumulation capacity and yield of maize

Maize (Zea mays) is an economic crop suitable for use in phytoremediation in low to moderately cadmium (Cd)-contaminated soils due to its ability to accumulate high concentration of Cd in parts of maize that are not used in human diet. The aim of this study was to test Cd content in nine female parents of the commercial maize hybrids (C1 = ♀2-48; C2 = ♀1767/99; C3 = ♀87-24; C4 = ♀135-88, C5 = ♀84-28; C6 = ♀84-44; C7 = ♀438-95; C8 = ♀30-8; C9 = ♀B-73) grown under field conditions in two soils (B1: eutric cambisol, B2: stagnosol) during three growing seasons (A1: 2006, A2: 2007, A3: 2008). The stationary trial was conducted in four replicates. The ear-leaves at flowering and grain at maturity were taken for chemical analysis. The average quantities of leaf-Cd were 0.081, 0.088 and 0.143 mg per kg of dry matter for A1, A2 and A3, 0.089 and 0.118, for B1 and B2, respectively. Grain-Cd was below the threshold (< 0.02 mg/kg). Five Cd-inefficient genotypes (C3, C5, C6, C7 and C9) had low leaf-Cd (average 0.049 mg/kg), while this content was about 6-times higher (average 0.299 mg/kg) in Cd-efficient genotype C4. The yield among the years ranged from 2.36 to 4.31 t/ha. Maize grown on B2 had about 26% lower yield than on B1. Five genotypes (C1, C2, C8 and C9) achieved yields less than 3.50 t/ha (mean 3.15 t/ha), while in two genotypes (C3 and C5) yields were above 4.00 t/ha (mean 4.14 t/ha). Very strong correlations (r) of leaf-Cd status among years (ranged from 0.52 to 0.77) confirmed high genetic effect on the capability of Cd accumulation in maize. However, correlations between Cd content and yield were low (ranged from -0.17 to 0.06). Cd-efficient C4 female parent could be used for development of maize hybrids suitable for phytoremediation, while Cd-inefficient female parents for hybrids could be suitable as forage maize crop contributing to the lower Cd input into food chain.