title: Uncovering of major genetic factors generating naturally occurring variation in heading date among Asian rice cultivars.
abstract: To dissect the genetic factors controlling naturally occurring variation of heading date in Asian rice cultivars, we performed QTL analyses using F(2) populations derived from crosses between a japonica cultivar, Koshihikari, and each of 12 cultivars originating from various regions in Asia. These 12 diverse cultivars varied in heading date under natural field conditions in Tsukuba, Japan. Transgressive segregation was observed in 10 F(2) combinations. QTL analyses using multiple crosses revealed a comprehensive series of loci involved in natural variation in flowering time. One to four QTLs were detected in each cross combination, and some QTLs were shared among combinations. The chromosomal locations of these QTLs corresponded well with those detected in other studies. The allelic effects of the QTLs varied among the cross combinations. Sequence analysis of several previously cloned genes controlling heading date, including Hd1, Hd3a, Hd6, RFT1, and Ghd7, identified several functional polymorphisms, indicating that allelic variation at these loci probably contributes to variation in heading date. Taken together, the QTL and sequencing results indicate that a large portion of the phenotypic variation in heading date in Asian rice cultivars could be generated by combinations of different alleles (possibly both loss- and gain-of-function) of the QTLs detected in this study.
authors.affiliation: QTL Genomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan.
authors.forename: Kaworu
authors.initials: K
authors.lastname: Ebana
authors.forename: Taeko
authors.initials: T
authors.lastname: Shibaya
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Wu
authors.forename: Kazuki
authors.initials: K
authors.lastname: Matsubara
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kanamori
authors.forename: Hiroko
authors.initials: H
authors.lastname: Yamane
authors.forename: Utako
authors.initials: U
authors.lastname: Yamanouchi
authors.forename: Tatsumi
authors.initials: T
authors.lastname: Mizubayashi
authors.forename: Izumi
authors.initials: I
authors.lastname: Kono
authors.forename: Ayahiko
authors.initials: A
authors.lastname: Shomura
authors.forename: Sachie
authors.initials: S
authors.lastname: Ito
authors.forename: Tsuyu
authors.initials: T
authors.lastname: Ando
authors.forename: Kiyosumi
authors.initials: K
authors.lastname: Hori
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yano
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D018556:Crops, Agricultural / Q000235:genetics; D008040:Genetic Linkage; D005819:Genetic Markers; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics*; D010641:Phenotype; D040641:Quantitative Trait Loci; D017422:Sequence Analysis, DNA
chemical_list: D005819:Genetic Markers