title: Mapping and application of the twin-grain1 gene in rice.
abstract: The map-based cloning and application of a flower organ number gene twin - grain1 provide great potential for improving seed production in hybrid rice. A new germplasm for high-yield rice breeding, the twin-grain1 (tg1) mutant with more than one grain in a glume, was obtained from the Zhejing 22 rice variety via physical mutagenesis. The mapping results showed that TG1 is allelic to FLORAL ORGAN NUMBER2 (FON2)/FLORAL ORGAN NUMBER4 (FON4), a flower organ number gene located at 88.7 cM on chromosome 11. The novel tg1 gene allele was introgressed into the cytoplasmic male sterility (CMS) line Zhejing 22A, giving rise to a new CMS line Zhejing 22-tg1A. The Zhejing 22-tg1A line showed enhanced glume opening and stigma exsertion, which increased the outcrossing rate in hybrid rice. A small-scale hybrid rice seed production test demonstrated that the grain yield of the Zhejing 22-tg1A/Zhejinghui 5 line was significantly increased compared to that of the Zhejing 22A/Zhejinghui 5 line. The plot yield evaluation of the F1hybrid lines showed a higher yield for the Zhejing 22-tg1A/Zhejinghui 5 line than that of the Zhejing 22A/Zhejinghui 5 line. The results implied great potentials for the tg1 gene in hybrid rice breeding.
authors.affiliation: State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China.
authors.forename: Shenghai
authors.initials: S
authors.lastname: Ye
authors.affiliation: Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China.
authors.forename: Weibing
authors.initials: W
authors.lastname: Yang
authors.affiliation: State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China.
authors.forename: Rongrong
authors.initials: R
authors.lastname: Zhai
authors.affiliation: State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China.
authors.forename: Yanting
authors.initials: Y
authors.lastname: Lu
authors.affiliation: State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China.
authors.forename: Junmei
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China. zhangxiaoming@mail.zaas.ac.cn.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Zhang
mesh_terms: D002874:Chromosome Mapping / Q000379:methods; D003001:Cloning, Molecular; D017343:Genes, Plant / Q000235:genetics*; D012275:Oryza / Q000235:genetics* / Q000254:growth & development; D000069600:Plant Breeding / Q000379:methods; D012639:Seeds / Q000235:genetics / Q000254:growth & development
keywords: Breeding application; Flower organ number; Hybrid rice; Map-based cloning; Mutant