Location: Hard Winter Wheat Genetics ResearchTitle: Selection of bread wheat for low grain cadmium concentration at the seedling stage using hydroponics versus molecular markers
|LIU, CAIXIA - University Of Nebraska|
|WATERS, BRIAN - University Of Nebraska|
|ESKRIDGE, KENT - University Of Nebraska|
|BAENZIGER, P. STEPHEN - University Of Nebraska|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/11/2018
Publication Date: 6/22/2018
Citation: Liu, C., Guttieri, M.J., Waters, B.M., Eskridge, K.M., Baenziger, P. 2018. Selection of bread wheat for low grain cadmium concentration at the seedling stage using hydroponics versus molecular markers. Crop Science. 59(3):945-956. https://doi.org/10.1007/s11104-018-3712-8.
Interpretive Summary: Human consumption of cadmium, a heavy metal, can pose a health concern. Bread wheat varies for the propensity to accumulate cadmium in grain. The current approach to breeding low-cadmium wheat is to measure cadmium in grain after harvest. However, more rapid tests are needed. This study tested the utility of two selection methods, DNA marker-based selection and hydroponic seedling selection, in offspring of a cross between a low and a moderately high grain-cadmium cultivar. The results of this study indicate that both DNA marker-based selection and hydroponic selection are effective tools for breeding. The combination of the two tools is most promising, as they appear to target different mechanisms of cadmium accumulation in grain. Offspring that were predicted to be high-cadmium in both tests, as a group, had the highest grain cadmium concentration.
Technical Abstract: The excessive accumulation of cadmium (Cd) in harvested crops grown on high Cd soils has increased public concerns for food safety. Due to the high consumption of bread wheat per capita, high concentration of Cd in wheat grain can significantly affect human health. Breeding is a promising way to reduce grain Cd concentration. However, a lack of efficient selection methods impedes breeding for low grain Cd concentration in bread wheat. In this study, a recombinant inbred population segregating for grain Cd concentration was used in this study to assess the efficacy of two selection methods for decreasing grain Cd concentration in bread wheat. A hydroponic selection method used shoot Cd concentration in two-week old seedlings and a marker-based selection used SNP markers associated with grain Cd concentration. Both methods effectively selected low Cd lines. Marker-based selection was superior to hygroponic selection in terms both of simplicity and response to selection. The SNP markers explained 20% of the phenotypic variation in grain Cd concentration with an additive effect fo 0.014 mg/kg. The hydroponic selection and marker-based selection may target two different and independent processes controlling grain Cd accumulation, and they had no effect on grain Zn and Fe concentration. The ALMT1-UPS4 marker associated with aluminum tolerance was not associated with the grain Cd concentration but increased grain Zn and Fe concentration. The Rht8-associated GWM261 allele 193 bp which tends to reduce plant height, was associated with increased grain Cd, Fe, Mg, Mn, and P concentration.