EFFECT OF CULTIVAR ON UPTAKE OF CADMIUM BY POTATO-TUBERS

Cadmium (Cd) accumulation in tubers by commercial potato cultivars was assessed at 12 sites around Australia having differing soil and environmental conditions. At all but two sites there were significant differences in tuber Cd concentrations between cultivars. Some major commercial cultivars had tuber Cd concentrations only half that of others. Advanced breeding lines showed further potential to reduce Cd accumulation. Mean tuber Cd concentrations of the 14 most common cultivars, averaged across all sites, ranged from 30 to 50 mu g kg(-1) fresh weight (FW), below the maximum permitted concentration (MPC) of 50 mu g kg(-1) of Cd (FW). However, at some sites certain cultivars exceeded the MPC. A modified joint regression analysis of the data indicated that no cultivars have consistently low or consistently high tuber Cd concentrations across a range of environments. While differences between cultivars were significant, the range in Cd concentrations found between sites was generally greater than the range in Cd concentrations between cultivars at any one site. Thus soil and other site factors (e.g. irrigation water quality, climate, etc.) play a dominant role in controlling Cd accumulation by current commercial cultivars and there is a need to breed new cultivars resistant to Cd accumulation under a wide range of environments.