title: [Mechanisms of subspecies differentiation in a filial generation of rice indica-japonica hybridization under different ecological conditions].
abstract: Indica-japonica hybridization is one of the most important breeding methods in China, whereas identifying subspecies differentiation mechanisms is the key in indica-japonica hybridization breeding. By using InDels (Insert/Deletion) and ILPs (Intron Length Polymorphism), an analysis was made on the F6 populations derived from the hybridization of indica-japonica (Qishanzhan/Akihikari) planted in Liaoning and Guangdong provinces and generated by bulk harvesting (BM), single-seed descent methods (SSD), and pedigree method (PM). No segregation distortion was observed for the BM and SSD populations. The frequency distribution of japonica kinship percentage (Dj) was concentrated in 40%-60%. The PM populations in the two provinces presented indica-deviated distribution (30%-55%), with significant difference between Guangdong (38%) and Liaoning (42%). In addition, there was a significant positive correlation between the Dj and the kinship of functional gene regions in the BM and SSD populations. However, part of the positive correlation was broken in the PM populations that showed a regular distribution in the genotype patterns of indica and japonica loci. The above results demonstrated that artificial selection could be the main factor affecting the population differentiation in indica-japonica hybridization, and, with the synergistic effect of natural selection, induced the phenomenon of segregation distortion. There existed a close relationship between the differentiation of subspecies and the important agronomic traits, which could be the main reason why indica-japonica hybridiation breeding could not achieve the expected effect of combining the two subspecies advantages.
authors.affiliation: Ministry of Agriculture Key Laboratory of Northeast Rice Biology and Breeding/Ministry of Education Key Laboratory of Northern Japonica Rice Genetics and Breeding, Rice Research Institute, Shenyang Agricultural University, Shenyang 110866, China. tony.w.china@gmail.com
authors.forename: He-Tong
authors.initials: HT
authors.lastname: Wang
authors.affiliation: Ministry of Agriculture Key Laboratory of Northeast Rice Biology and Breeding/Ministry of Education Key Laboratory of Northern Japonica Rice Genetics and Breeding, Rice Research Institute, Shenyang Agricultural University, Shenyang 110866, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Jin
authors.affiliation: Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China.
authors.forename: Yi-Jun
authors.initials: YJ
authors.lastname: Jiang
authors.affiliation: Guangdong Province General Startion for Crop Technology Extension, Guangzhou 510500, China.
authors.forename: Qing-Shan
authors.initials: QS
authors.lastname: Lin
authors.affiliation: Ministry of Agriculture Key Laboratory of Northeast Rice Biology and Breeding/Ministry of Education Key Laboratory of Northern Japonica Rice Genetics and Breeding, Rice Research Institute, Shenyang Agricultural University, Shenyang 110866, China.
authors.forename: Hai
authors.initials: H
authors.lastname: Xu
authors.affiliation: Ministry of Agriculture Key Laboratory of Northeast Rice Biology and Breeding/Ministry of Education Key Laboratory of Northern Japonica Rice Genetics and Breeding, Rice Research Institute, Shenyang Agricultural University, Shenyang 110866, China.
authors.forename: Wen-Fu
authors.initials: WF
authors.lastname: Chen
authors.affiliation: Ministry of Agriculture Key Laboratory of Northeast Rice Biology and Breeding/Ministry of Education Key Laboratory of Northern Japonica Rice Genetics and Breeding, Rice Research Institute, Shenyang Agricultural University, Shenyang 110866, China.
authors.forename: Zheng-Jin
authors.initials: ZJ
authors.lastname: Xu
mesh_terms: D000383:Agriculture / Q000379:methods*; D002681:China; D017753:Ecosystem; D014644:Genetic Variation; D005838:Genotype; D006824:Hybridization, Genetic; D012275:Oryza / Q000235:genetics / Q000254:growth & development*