title: Progress in research and development on hybrid rice: a super-domesticate in China.
abstract: BACKGROUND
  China has been successful in breeding hybrid rice strains, but is now facing challenges to develop new hybrids with high-yielding potential, better grain quality, and tolerance to biotic and abiotic stresses. This paper reviews the most significant advances in hybrid rice breeding in China, and presents a recent study on fine-mapping quantitative trait loci (QTLs) for yield traits.
  
  
  METHODS
  By exploiting new types of male sterility, hybrid rice production in China has become more diversified. The use of inter-subspecies crosses has made an additional contribution to broadening the genetic diversity of hybrid rice and played an important role in the breeding of super rice hybrids in China. With the development and application of indica-inclined and japonica-inclined parental lines, new rice hybrids with super high-yielding potential have been developed and are being grown on a large scale. DNA markers for subspecies differentiation have been identified and applied, and marker-assisted selection performed for the development of restorer lines carrying disease resistance genes. The genetic basis of heterosis in highly heterotic hybrids has been studied, but data from these studies are insufficient to draw sound conclusions. In a QTL study using stepwise residual heterozygous lines, two linked intervals harbouring QTLs for yield traits were resolved, one of which was delimited to a 125-kb region.
  
  
  CONCLUSIONS
  Advances in rice genomic research have shed new light on the genetic study and germplasm utilization in rice. Molecular marker-assisted selection is a powerful tool to increase breeding efficiency, but much work remains to be done before this technique can be extended from major genes to QTLs.
authors: Chinese National Center for Rice Improvement and State Key Laboratory of Rice Biology, China National Rice Research Institute (CNRRI), Hangzhou 310006, China. shcheng@mail.hz.zj.cn
authors: Shi-Hua
authors: SH
authors: Cheng
authors: Jie-Yun
authors: JY
authors: Zhuang
authors: Ye-Yang
authors: YY
authors: Fan
authors: Jing-Hong
authors: JH
authors: Du
authors: Li-Yong
authors: LY
authors: Cao
mesh_terms: D000383:Agriculture / Q000639:trends*; D002681:China; D002874:Chromosome Mapping; D018556:Crops, Agricultural / Q000235:genetics*; D005819:Genetic Markers; D006824:Hybridization, Genetic; D012275:Oryza / Q000235:genetics*; D051479:Plant Infertility; D040641:Quantitative Trait Loci
chemical_list: D005819:Genetic Markers
references: Theor Appl Genet. 2005 Jun;111(1):50-6
references: 15856160
references: Theor Appl Genet. 1994 Apr;88(1):65-9
references: 24185883
references: Theor Appl Genet. 2002 Dec;105(8):1137-1145
references: 12582891
references: Genetics. 2002 Dec;162(4):1885-95
references: 12524357
references: Sheng Wu Gong Cheng Xue Bao. 2003 Mar;19(2):153-7
references: 15966313
references: Sci China C Life Sci. 2001 Jun;44(3):327-36
references: 18726413
references: Proc Natl Acad Sci U S A. 1997 Aug 19;94(17):9226-31
references: 11038567
references: Theor Appl Genet. 1996 May;92(6):637-43
references: 24166385
references: Genetics. 1995 Jun;140(2):745-54
references: 7498751
references: Theor Appl Genet. 1996 Dec;93(8):1218-24
references: 24162533
references: Genetics. 2001 Aug;158(4):1737-53
references: 11514459
references: Theor Appl Genet. 1995 May;90(6):878-84
references: 24172933
references: Theor Appl Genet. 2005 Feb;110(4):634-9
references: 15657740