title: Differential contribution of two Ppd-1 homoeoalleles to early-flowering phenotype in Nepalese and Japanese varieties of common wheat.
abstract: Wheat landraces carry abundant genetic variation in heading and flowering times. Here, we studied flowering-related traits of two Nepalese varieties, KU-4770 and KU-180 and a Japanese wheat cultivar, Shiroganekomugi (SGK). These three wheat varieties showed similar flowering time in a common garden experiment. In total, five significant quantitative trait loci (QTLs) for three examined traits, the heading, flowering and maturation times, were detected using an F2 population of SGK/KU-4770. The QTLs were found at the Ppd-1 loci on chromosomes 2B and 2D and the 2B QTL was also confirmed in another F2 population of SGK/KU-180. The Ppd-D1 allele from SGK and the Ppd-B1 alleles from the two Nepalese varieties might be causal for early-flowering phenotype. The SGK Ppd-D1 allele contained a 2-kb deletion in the 5' upstream region, indicating a photoperiod-insensitive Ppd-D1a allele. Real-time PCR analysis estimating the Ppd-B1 copy number revealed that the two Nepalese varieties included two intact Ppd-B1 copies, putatively resulting in photoperiod insensitivity and an early-flowering phenotype. The two photoperiod-insensitive Ppd-1 homoeoalleles could independently contribute to segregation of early-flowering individuals in the two F2 populations. Therefore, wheat landraces are genetic resources for discovery of alleles useful for improving wheat heading or flowering times.
authors.affiliation: Graduate School of Agricultural Science, Kobe University , 1-1 Rokkodai, Nada, Kobe, Hyogo 657-8501 , Japan.
authors.forename: Anh T
authors.initials: AT
authors.lastname: Nguyen
authors.affiliation: Graduate School of Agricultural Science, Kobe University , 1-1 Rokkodai, Nada, Kobe, Hyogo 657-8501 , Japan.
authors.forename: Julio C M
authors.initials: JC
authors.lastname: Iehisa
authors.affiliation: Graduate School of Agriculture, Kyoto University , Kitashirakawa Oiwake, Sakyo, Kyoto 606-8502 , Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Mizuno
authors.affiliation: Graduate School of Agriculture, Kyoto University , Kitashirakawa Oiwake, Sakyo, Kyoto 606-8502 , Japan.
authors.forename: Miyuki
authors.initials: M
authors.lastname: Nitta
authors.affiliation: Graduate School of Agriculture, Kyoto University , Kitashirakawa Oiwake, Sakyo, Kyoto 606-8502 , Japan.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Nasuda
authors.affiliation: Graduate School of Agricultural Science, Kobe University , 1-1 Rokkodai, Nada, Kobe, Hyogo 657-8501 , Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Takumi
keywords: Triticum aestivum L.; copy number variation; flowering time; landraces; photoperiodic sensitivity