title: Genetic Diversity, Rather than Cultivar Type, Determines Relative Grain Cd Accumulation in Hybrid Rice.
abstract: Cadmium (Cd) is a toxic element, and rice is known to be a leading source of dietary Cd for people who consume rice as their main caloric resource. Hybrid rice has dominated rice production in southern China and has been adopted worldwide. The characteristics of high yield heterosis of rice hybrids makes the public think intuitively that the hybrid rice accumulates more Cd in grain than do inbred cultivars. A detailed understanding of the genetic basis of grain Cd accumulation in hybrids and developing Cd-safe rice are one of the top priorities for hybrid rice breeders at present. In this study, we investigated genetic diversity and grain Cd levels in 617 elite rice hybrids collected from the middle and lower Yangtze River Valley in China and 68 inbred cultivars from around the world. We found that there are large variations in grain Cd accumulation in both the hybrids and their inbred counterparts. However, we found grain Cd levels in the rice hybrids to be similar to the levels inindicarice inbreds, suggesting that the hybrids do not accumulate more Cd than do the inbred rice cultivars. Further analysis revealed that the high heritability of Cd accumulation in the grain and the singleindicapopulation structure increases the risk of Cd over-accumulation in hybrid rice. The genetic effects of Cd-related QTLs, which have been identified in related Cd-QTL mapping studies, were also determined in the hybrid rice population. Four QTLs were identified as being associated with the variation in grain Cd levels; three of these loci exhibited obviousindica-japonicadifferentiations. Our study will provide a better understanding of grain Cd accumulations in hybrid rice, and pave the way toward effective breeding for high-yielding, low grain-Cd hybrids in the future.
authors.affiliation: Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences Changsha, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Sun
authors.affiliation: Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences Changsha, China.
authors.forename: Xiaxu
authors.initials: X
authors.lastname: Xu
authors.affiliation: Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of SciencesChangsha, China; Institute of Rice Science, Hunan Agricultural UniversityChangsha, China.
authors.forename: Youru
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences Changsha, China.
authors.forename: Qihong
authors.initials: Q
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences Changsha, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Yang
authors.affiliation: Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of SciencesChangsha, China; Institute of Rice Science, Hunan Agricultural UniversityChangsha, China.
authors.forename: Jieqiang
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Yuanlongping High-Tech Agriculture Co., LTD Changsha, China.
authors.forename: Yuanzhu
authors.initials: Y
authors.lastname: Yang
authors.affiliation: China National Hybrid Rice R&D Center Changsha, China.
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Huang
authors.affiliation: Lixiahe Agricultural Research Institute of Jiangsu Province Yangzhou, China.
authors.forename: Aihong
authors.initials: A
authors.lastname: Li
authors.affiliation: Beishan Agricultural Service Center of Changsha County Changsha, China.
authors.forename: Lianghui
authors.initials: L
authors.lastname: Chen
authors.affiliation: Institute of Rice Science, Hunan Agricultural University Changsha, China.
authors.forename: Wenbang
authors.initials: W
authors.lastname: Tang
authors.affiliation: Beishan Agricultural Service Center of Changsha County Changsha, China.
authors.forename: Guoyu
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences Changsha, China.
authors.forename: Jiurong
authors.initials: J
authors.lastname: Wang
authors.affiliation: Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences Changsha, China.
authors.forename: Guoying
authors.initials: G
authors.lastname: Xiao
authors.affiliation: Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences Changsha, China.
authors.forename: Daoyou
authors.initials: D
authors.lastname: Huang
authors.affiliation: Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences Changsha, China.
authors.forename: Caiyan
authors.initials: C
authors.lastname: Chen
keywords: QTL; cadmium; genetic diversity; hybrid rice; indica