DIFFERENTIAL RESPONSES OF AUSTRALIAN WHEAT CULTIVARS TO CADMIUM CONCENTRATION IN WHEAT-GRAIN

Cadmium concentration in grain was studied for wheat cultivars grown n ationally in the Interstate Wheat Variety (IWV) experiments (1988 and 1989) and cultivars grown in the Western Australian (WA) experiments ( 1990-1992). These experiments covered a range of differing soil and en vironmental conditions. The adaptation of these cultivars to changes i n cadmium potential at a site was determined. Significant cultivar eff ects were identified, but these were less significant than the site ef fects. The Cd concentrations in grain exceeded the current Australian maximum permitted concentration (MPC) of 0.05 mg kg-1 at one site in t he IWV experiments while the concentration exceeded the MPC at a large r proportion of sites in the WA experiments. Several trends in cultiva r accumulation of Cd in grain were evident. Reeves and Kulin were foun d to have the highest Cd concentration at a number of sites for severa l years in both the IWV and WA experiments. The similar pedigrees of t hese two cultivars suggest that while wheat breeders were selecting fo r certain traits during the breeding selection process, they were inad vertently selecting for the ability to accumulate Cd. In the 1992 WA c ultivar experiments, generally Aroona had the highest Cd concentration in grain. Aroona has a different pedigree to Reeves and Kulin. Severa l of the cultivars that were low Cd accumulators also had similar pedi grees. This indicates that there is potential for selecting lines that are low Cd accumulators to be grown in areas where Cd accumulation in grain is a problem.