Breeding for Rice Cultivars with Low Cadmium Accumulation

Cadmium (Cd) contamination in paddy fields leads to different degrees of Cd accumulation in rice. Rice ( Oryza sativa L.) with excessive Cd in grains is the major source of Cd intake, which seriously threatens the health of people consuming rice as the staple food. Breeding rice cultivars with low-Cd accumulation in grains is the most cost-effective and eco-friendly strategy to tackle this problem and is of great significance to realize the safe production of rice in Cd-contaminated fields. In recent years, great progress has been made in the molecular mechanisms of Cd accumulation in rice, providing clues for breeding low-Cd rice cultivars, while genetic engineering, genome editing, physical and chemical mutagenesis, and molecular marker-assisted selection have provided technical support for low-Cd rice breeding. On this basis, low-Cd rice breeding is progressively advancing toward precision and high efficiency. This chapter mainly reviews the molecular mechanisms of uptake, translocation, and distribution of Cd in rice, as well as the progress of rice breeding with low Cd accumulation, and prospects the future development directions.