Soybean cadmium concentration: validation of a QTL affecting seed cadmium accumulation for improved food safety

Soybean can accumulate considerable amounts of cadmium depending on soil conditions. As low cadmium concentration of soybean is of great interest in soy food production, a major quantitative trait locus described earlier for controlling cadmium accumulation in the seed was utilized to classify early maturity genotypes with respect to cadmium uptake and to verify their cadmium accumulation level. Marker-selected soybean genotypes were then tested for cadmium accumulation in a pot experiment with three cadmium levels and at three field locations in Austria. Out of 48 soybean genotypes, 19 exhibited the microsatellite marker allele associated with low cadmium accumulation. In the pot experiment, seed cadmium concentration was below 0.15 mg kg−1 in low cadmium accumulating genotypes while it reached over 0.30 mg kg−1 in genotypes carrying the high cadmium allele. In field experiments, cadmium concentration was in the range between 0.03 and 0.16 mg kg−1, and both the cadmium accumulation locus as well as the experimental locations had a significant influence on seed cadmium. Marker-assisted selection of soybean genotypes for low cadmium accumulation could thus contribute to improved food safety which is particularly important for environments with unknown cadmium status of soil.