title: Hierarchical additive effects on heterosis in rice (Oryza sativa L.).
abstract: Exploitation of heterosis in crops has contributed greatly to improvement in global food and energy production. In spite of the pervasive importance of heterosis, a complete understanding of its mechanisms has remained elusive. In this study, a small test-crossed rice population was constructed to investigate the formation mechanism of heterosis for 13 traits. The results of the relative mid-parent heterosis and modes of inheritance of all investigated traits demonstrated that additive effects were the foundation of heterosis for complex traits in a hierarchical structure, and multiplicative interactions among the component traits were the framework of heterosis in complex traits. Furthermore, new balances between unit traits and related component traits provided hybrids with the opportunity to achieve an optimal degree of heterosis for complex traits. This study dissected heterosis of both reproductive and vegetative traits from the perspective of hierarchical structure for the first time. Additive multiplicative interactions of component traits were proven to be the origin of heterosis in complex traits. Meanwhile, more attention should be paid to component traits, rather than complex traits, in the process of revealing the mechanism of heterosis.
authors.affiliation: State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University Wuhan, China ; Key Laboratory for Research and Utilization of Heterosis in Indica Rice, Ministry of Agriculture, Wuhan University Wuhan, China ; The Yangzte River Valley Hybrid Rice Collaboration Innovation Center, Wuhan University Wuhan, China.
authors.forename: Zhiwu
authors.initials: Z
authors.lastname: Dan
authors.affiliation: State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University Wuhan, China ; Key Laboratory for Research and Utilization of Heterosis in Indica Rice, Ministry of Agriculture, Wuhan University Wuhan, China ; The Yangzte River Valley Hybrid Rice Collaboration Innovation Center, Wuhan University Wuhan, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University Wuhan, China ; Key Laboratory for Research and Utilization of Heterosis in Indica Rice, Ministry of Agriculture, Wuhan University Wuhan, China ; The Yangzte River Valley Hybrid Rice Collaboration Innovation Center, Wuhan University Wuhan, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University Wuhan, China ; Key Laboratory for Research and Utilization of Heterosis in Indica Rice, Ministry of Agriculture, Wuhan University Wuhan, China ; The Yangzte River Valley Hybrid Rice Collaboration Innovation Center, Wuhan University Wuhan, China.
authors.forename: Guoxin
authors.initials: G
authors.lastname: Yao
authors.affiliation: State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University Wuhan, China ; Key Laboratory for Research and Utilization of Heterosis in Indica Rice, Ministry of Agriculture, Wuhan University Wuhan, China ; The Yangzte River Valley Hybrid Rice Collaboration Innovation Center, Wuhan University Wuhan, China.
authors.forename: Renshan
authors.initials: R
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University Wuhan, China ; Key Laboratory for Research and Utilization of Heterosis in Indica Rice, Ministry of Agriculture, Wuhan University Wuhan, China ; The Yangzte River Valley Hybrid Rice Collaboration Innovation Center, Wuhan University Wuhan, China.
authors.forename: Wenchao
authors.initials: W
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University Wuhan, China ; Key Laboratory for Research and Utilization of Heterosis in Indica Rice, Ministry of Agriculture, Wuhan University Wuhan, China ; The Yangzte River Valley Hybrid Rice Collaboration Innovation Center, Wuhan University Wuhan, China.
authors.forename: Yingguo
authors.initials: Y
authors.lastname: Zhu
keywords: additive effects; heterosis; hierarchical structure; hybrids; multiplicative interactions; rice (Oryza sativa L.)