title: QTL Mapping of Grain Quality Traits Using Introgression Lines Carrying Oryza rufipogon Chromosome Segments in Japonica Rice.
abstract: BACKGROUND
  Improved eating quality is a major breeding target in japonica rice due to market demand. Consequently, quantitative trait loci (QTL) for glossiness of cooked rice and amylose content associated with eating quality have received much research focus because of their importance in rice quality.
  
  
  RESULTS
  In this study, QTL associated with 12 grain quality traits were identified using 96 introgression lines (IL) of rice developed from an interspecific cross between the Korean elite O. sativa japonica cultivar 'Hwaseong' and O. rufipogon over 7 years. QTL analyses indicated that QTL qDTH6 for heading date, detected on chromosome 6 is associated with variance in grain traits. Most QTLs detected in this study clustered near the qDTH6 locus on chromosome 6, suggesting the effect of qDTH6. O. rufipogon alleles negatively affected grain quality traits except for a few QTLs, including qGCR9 for glossiness of cooked rice on chromosome 9. To characterize the effect of the O. rufipogon locus harboring qGCR9, four lines with a single but different O. rufipogon segment near qGCR9 were compared to Hwaseong. Three lines (O. rufipopgon ILs) having O. rufipogon segment between RM242 and RM245 in common showed higher glossiness of cooked rice than Hwaseong and the other line (Hwaseong IL), indicating that qGCR9 is located in the 3.4-Mb region between RM242 and RM245. Higher glossiness of cooked rice conferred by the O. rufipogon allele might be associated with protein content considering that three lines had lower protein content than Hwaseong (P < 0.1). These three O. rufipogon ILs showed higher yield than Hwaseong and Hwaseong IL due to increase in spikelets per panicle and grain weight indicating the linkage of qGCR9 and yield component QTLs.
  
  
  CONCLUSIONS
  The qGCR9 locus is of particular interest because of its independence from other undesirable grain quality traits in O. rufipogon. SSR markers linked to qGCR9 can be used to develop high-quality japonica lines and offer a starting point for map-based cloning of genes underlying this trait. To our knowledge, this is the first report to map a beneficial QTL for glossiness of cooked rice from a wild rice, O. rufipogon.
authors.affiliation: Chungcheongnamdo Agricultural Research and Extension Services, Yesan, 340-861, Korea.
authors.forename: Yeo-Tae
authors.initials: YT
authors.lastname: Yun
authors.affiliation: Chungcheongnamdo Agricultural Research and Extension Services, Yesan, 340-861, Korea.
authors.forename: Chong-Tae
authors.initials: CT
authors.lastname: Chung
authors.affiliation: Chungcheongnamdo Agricultural Research and Extension Services, Yesan, 340-861, Korea.
authors.forename: Young-Ju
authors.initials: YJ
authors.lastname: Lee
authors.affiliation: Chungcheongnamdo Agricultural Research and Extension Services, Yesan, 340-861, Korea.
authors.forename: Han-Jung
authors.initials: HJ
authors.lastname: Na
authors.affiliation: Chungcheongnamdo Agricultural Research and Extension Services, Yesan, 340-861, Korea.
authors.forename: Jae-Chul
authors.initials: JC
authors.lastname: Lee
authors.affiliation: Chungcheongnamdo Agricultural Research and Extension Services, Yesan, 340-861, Korea.
authors.forename: Sun-Gye
authors.initials: SG
authors.lastname: Lee
authors.affiliation: Chungcheongnamdo Agricultural Research and Extension Services, Yesan, 340-861, Korea.
authors.forename: Kwang-Won
authors.initials: KW
authors.lastname: Lee
authors.affiliation: Chungcheongnamdo Agricultural Research and Extension Services, Yesan, 340-861, Korea.
authors.forename: Young-Hwan
authors.initials: YH
authors.lastname: Yoon
authors.affiliation: College of Agriculture & Life Sciences, Chungnam National University, Daejeon, 305-764, Korea.|Department of Southern Area Crop Science, National Institute of Crop Science, Milyang, 50424, Korea.
authors.forename: Ju-Won
authors.initials: JW
authors.lastname: Kang
authors.affiliation: College of Agriculture & Life Sciences, Chungnam National University, Daejeon, 305-764, Korea.
authors.forename: Hyun-Sook
authors.initials: HS
authors.lastname: Lee
authors.affiliation: National Academy of Agricultural Sciences, Rural Development Admin., Jeonju, 560-500, Korea.
authors.forename: Jong-Yeol
authors.initials: JY
authors.lastname: Lee
authors.affiliation: College of Agriculture & Life Sciences, Chungnam National University, Daejeon, 305-764, Korea. ahnsn@cnu.ac.kr.
authors.forename: Sang-Nag
authors.initials: SN
authors.lastname: Ahn
keywords: Grain quality; Interspecific cross; Introgression lines; QTL; Rice