Genetic Variance in Cadmium Tolerance and Accumulation in Wheat Materials Differing in Ploidy and Genome at Seedling Stage

Abstract

AbstractCadmium (Cd) tolerance and accumulation in wheat varieties differing in ploidy and genome were investigated at seedling stage under controlled environmental conditions. The wheat varieties included six diploid, eight tetraploid, seven hexaploid and three octoploid species together with wheat relatives containing different genomes. Parameters of growth and photosynthesis were measured and the ratio of a given parameter under Cd treatment to that of the control was referred to as the Cd‐tolerant index of this parameter. Cd concentrations in shoots and roots, Cd accumulation in shoots (SCA) and Cd translocation (ratio of SCA to total Cd accumulation in plants) of the wheat varieties differing in ploidies generally decreased from octoploid to diploid, except for material containing the CCUU genome. It was found that Cd tolerance of these 24 wheat varieties varied with different ploidy and genomes at seedling stage. B and D genomes played a positive role, whereas the R genome played a negative role in Cd tolerance. By contrast, there were no significant differences between ploidies in Cd tolerance based on the observed growth and photosynthesis parameters. Using principal components analysis and cluster analysis, Triticum boeoticum Boiss was found to be the most Cd‐tolerant variety exhibiting low Cd translocation rates, whereas T. aestivum cv. Huixianhong and Jinghui 1 were identified as the most Cd‐sensitive varieties showing also higher Cd translocation rates.