title: Combinations of Hd2 and Hd4 genes determine rice adaptability to Heilongjiang Province, northern limit of China.
abstract: Heading date is a key trait in rice domestication and adaption, and a number of quantitative trait loci (QTLs) have been identified. The rice (Oryza sativa L.) cultivars in the Heilongjiang Province, the northernmost region of China, have to flower extremely early to fulfill their life cycle. However, the critical genes or different gene combinations controlling early flowering in this region have not been determined. QTL and candidate gene analysis revealed that Hd2/Ghd7.1/OsPRR37 plays a major role in controlling rice distribution in Heilongjiang. Further association analysis with a collection of rice cultivars demonstrated that another three major QTL genes (Hd4/Ghd7, Hd5/DTH8/Ghd8, and Hd1) also participate in regulating heading date under natural long day (LD) conditions. Hd2/Ghd7.1/OsPRR37 and Hd4/Ghd7 are two major QTLs and function additively. With the northward rice cultivation, the Hd2/Ghd7.1/OsPRR37 and Hd4/Ghd7 haplotypes became non-functional alleles. Hd1 might be non-functional in most Heilongjiang rice varieties, implying that recessive hd1 were selected during local rice breeding. Non-functional Hd5/DTH8/Ghd8 is very rare, but constitutes a potential target for breeding extremely early flowering cultivars. Our results indicated that diverse genetic combinations of Hd1, Hd2, Hd4, and Hd5 determined the different distribution of rice varieties in this northernmost province of China.
authors.affiliation: Northeast Institute of Geography and Agroecology, Key Laboratory of Soybean Molecular Design Breeding, the Chinese Academy of Sciences, Harbin, 150081, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Xiufeng
authors.initials: X
authors.lastname: Li
authors.affiliation: Northeast Institute of Geography and Agroecology, Key Laboratory of Soybean Molecular Design Breeding, the Chinese Academy of Sciences, Harbin, 150081, China.|Rice Research Institute, Heilongjiang Academy of Land Reclamation Sciences, Jiamusi, 154007, China.
authors.forename: Huazhao
authors.initials: H
authors.lastname: Liu
authors.affiliation: Beidahuang Kenfeng Seed Co. Ltd., Harbin, 150090, China.
authors.forename: Maoqing
authors.initials: M
authors.lastname: Wang
authors.affiliation: College of Agriculture, Northeast Agricultural University, Harbin, 150030, China.
authors.forename: Hualong
authors.initials: H
authors.lastname: Liu
authors.affiliation: Northeast Institute of Geography and Agroecology, Key Laboratory of Soybean Molecular Design Breeding, the Chinese Academy of Sciences, Harbin, 150081, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Xiaojie
authors.initials: X
authors.lastname: Tian
authors.affiliation: Northeast Institute of Geography and Agroecology, Key Laboratory of Soybean Molecular Design Breeding, the Chinese Academy of Sciences, Harbin, 150081, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Wenjia
authors.initials: W
authors.lastname: Zhou
authors.affiliation: Northeast Institute of Geography and Agroecology, Key Laboratory of Soybean Molecular Design Breeding, the Chinese Academy of Sciences, Harbin, 150081, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Tianxiao
authors.initials: T
authors.lastname: Lü
authors.affiliation: Northeast Institute of Geography and Agroecology, Key Laboratory of Soybean Molecular Design Breeding, the Chinese Academy of Sciences, Harbin, 150081, China.
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Chengcai
authors.initials: C
authors.lastname: Chu
authors.affiliation: State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Fang
authors.affiliation: Northeast Institute of Geography and Agroecology, Key Laboratory of Soybean Molecular Design Breeding, the Chinese Academy of Sciences, Harbin, 150081, China.
authors.forename: Qingyun
authors.initials: Q
authors.lastname: Bu
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D000483:Alleles; D002681:China; D035264:Flowers / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D014644:Genetic Variation; D005838:Genotype; D007178:Inbreeding; D012275:Oryza / Q000033:anatomy & histology / Q000235:genetics* / Q000502:physiology*; D010641:Phenotype; D011485:Protein Binding; D040641:Quantitative Trait Loci / Q000235:genetics; D011995:Recombination, Genetic / Q000235:genetics; D020798:Two-Hybrid System Techniques
keywords: Hd1; Hd2; Hd4; Hd5; Rice; heading date