Differential responses of one hundred tomato genotypes grown under cadmium stress

Due to increased global concern over the deleterious effects of toxic heavy metals in the environment, it has become necessary to develop plant genotypes that limit the uptake of heavy metals to aerial edible parts. To address this concern, we performed a glasshouse experiment to assess variations within tomato germplasm for cadmium (Cd) tolerance under control conditions and under simulated stress conditions. Significant differences (P < 0.01) were observed among all genotypes at both Cd levels (3 ppm and 6 ppm). Our analyses showed that the genotypes 9086, Roma, Sitara TS-01, pak0010990, CLN-2123A, Picdeneato, 0.006231, and 7035 gave the best yields with minimum Cd content in their fruit, whereas the genotypes 42-07, 17883, BL-1176-Riostone-1-1, Marmande, and 17882 had relatively low yields with higher metal contents. The heavy metal was found to accumulate first in the shoot, then fruit, leaf, and finally root in tolerant genotypes; in susceptible genotypes, the order was fruit, shoot, leaf, and root. The inter-genotype differences in Cd uptake indicated the possibility of manipulating tomato genotypes to develop Cd tolerant tomato varieties or hybrids that allow safe use of a tomato crop grown on Cd contaminated soils.