Cadmium concentration in terminal tissues as tools to select low-cadmium wheat

Background and aim The consumption of cadmium-contaminated food adversely affects human health. Heritable variation for the propensity to accumulate cadmium in the grain exists, but is a difficult selection target, given the practical limitations of breeding operations. The main objective of this study is to assess the feasibility and accuracy of selecting low-cadmium lines during grain filling using cadmium concentration in terminal tissues. Methods Cadmium and other mineral concentrations in terminal tissues of two low- and high-cadmium winter wheat cultivars ( Triticum aestivum L.) were measured at 2, 3, 4, and 5 weeks after average anthesis (WAAA) and at maturity in two years. Results Cadmium concentration in grain at 3 and 4 WAAA, in rachis at 2, 4 and 5 WAAA, and in the terminal vegetative node at 3 and 4 WAAA separated high- and low-cadmium cultivars. Controlling disease with fungicides did not affect the ability to select low-cadmium cultivars. Across environments, low-cadmium cultivars had lower concentration of cadmium, but similar concentration of iron and zinc in developing and mature grains, compared to the high-cadmium cultivars. Conclusions Low-cadmium lines can be selected before harvest using Cd concentration in terminal tissues. It is possible to select low-cadmium lines that are consistently low across environments.