title: Detection of QTL for exudation rate at ripening stage in rice and its contribution to hydraulic conductance.
abstract: Dry matter production of crops is determined by how much light they intercept and how efficiently they use it for carbon fixation; i.e., photosynthesis. The high-yielding rice cultivar, Akenohoshi, maintains a high photosynthetic rate in the middle of the day owing to its high hydraulic conductance in comparison with the elite commercial rice cultivar, Koshihikari. We developed 94 recombinant inbred lines derived from Akenohoshi and Koshihikari and measured their exudation rate to calculate hydraulic conductance to osmotic water transport in a paddy field. A quantitative trait locus (QTL) for exudation rate was detected on the long arm of chromosome 2 at the heading and ripening stages. We developed chromosome segment substitution lines which carried Akenohoshi segments in the Koshihikari genetic background, and measured hydraulic conductance to both osmotic and passive water transport. The QTL was confirmed to be located within a region of about 4.2Mbp on the distal end of long arm of chromosome 2. The Akenohoshi allele increased root surface area and hydraulic conductance, but didn't increase hydraulic conductivity of a plant.
authors.affiliation: National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, 305-8602, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan.
authors.forename: Tadafumi
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Suzuki
authors.affiliation: National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, 305-8602, Japan; Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan; NARO Institute of Crop Science, Tsukuba, Ibaraki, 305-8518, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Adachi
authors.affiliation: National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, 305-8602, Japan.
authors.forename: Jian
authors.initials: J
authors.lastname: Sun
authors.affiliation: National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, 305-8602, Japan; NARO Institute of Crop Science, Tsukuba, Ibaraki, 305-8518, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yano
authors.affiliation: Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan.
authors.forename: Taiichiro
authors.initials: T
authors.lastname: Ookawa
authors.affiliation: Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Hirasawa
mesh_terms: D001692:Biological Transport / Q000235:genetics; D002874:Chromosome Mapping / Q000379:methods; D032461:Chromosomes, Plant / Q000235:genetics; D057446:Hydrodynamics; D007178:Inbreeding; D012275:Oryza / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D040641:Quantitative Trait Loci / Q000235:genetics*; D013045:Species Specificity; D013997:Time Factors; D014867:Water / Q000378:metabolism; D052584:Xylem / Q000235:genetics* / Q000378:metabolism
chemical_list: D014867:Water
keywords: Hydraulic conductance; Hydraulic conductivity; Quantitative trait locus; Rice; Root surface area