Genotypic variation in kernel heavy metal concentrations in barley and as affected by soil factors

Genotypic variation in kernel heavy metal concentrations was studied for barley (Hordeum vulgare L.) cultivars grown in six locations of Zhejiang, China. These sites covered a wide range of soils and climates. The results showed that barley kernels produced at some sites contained heavy metals higher than the Maximum Permitted Concentration (MPC). Significant cultivar effects were identified, but these were less than the site effects. Although Genotype x Location effect existed, genotypes performed consistently across six locations. Meanwhile, there were significant positive correlations between heavy metal concentrations in barley grain, indicating that there is potential for developing cultivars that are low heavy metal accumulators. Soil properties such as pH, and EDTA-extractable heavy metal content played an important role in heavy metal uptake and accumulation in barley. Data from the six soils showed that the soil in Ningbo was lower in pH and contained the highest EDTA-cadmium (Cd), copper (Cu), and chromium (Cr), causing significantly higher kernel Cd, Cu, and Cr concentrations in barley grains. Kernel Cd, zinc (Zn), Cr, manganese (Mn), and iron (Fe) concentrations were closer to EDTA-extractable corresponding metal contents than to soil pH. Regression equations between kernel Cd, Zn, Cr, Mn, and Fe concentrations and its EDTA-extractable contents were established and suggested to be used in predicting soil critical levels of these metals for safe barley production.