Screening stably low cadmium and moderately high micronutrients wheat cultivars under three different agricultural environments of China

Heavy metal-contaminated farmland, especially for cadmium (Cd), is being used for agricultural production in large scale due to the increasing food demand. Thus, minimizing the influx of Cd to the human food chain is urgently needed. Screening for stably low Cd and moderately high micronutrient wheat cultivars is one of the most feasible and effective approaches to ensure food safety and quality. Here, the Cd accumulation by 72 wheat cultivars was identified in field 1, and the stability of Cd accumulation in these cultivars was tested in fields 2 and 3. The effects of Cd on micronutrient (zinc (Zn), copper (Cu), iron (Fe), manganese (Mn), and boron (B)) uptake in grains were also investigated. Nine of the 24 low-Cd wheat cultivars identified by screening showed stably low-Cd and moderately high micronutrient concentrations in grain. Nine cultivars exhibited unstable low-Cd accumulation characteristics, and another five cultivars contained significantly lower Zn concentrations in grain in at least two experimental fields. One low-Cd cultivar also had low Zn, Cu and Mn concentrations in grain. The accumulation of Cd in wheat grain had little effects on the uptake of Fe. Grain Cd concentration correlated positively with the dry weight of stem and root, and negatively with the spike length. There was no correlation between grain Cd concentration and wheat yield. The selected cultivars with stably low-Cd accumulation and moderately high micronutrient concentrations in grain are recommended for cultivation in slightly to moderately Cd-contaminated farmland to ensure food safety for the growing human population.