title: Genotypic difference in canopy diffusive conductance measured by a new remote-sensing method and its association with the difference in rice yield potential.
abstract: There have been few practical ways of measuring physiological determinants of rice yield. Rapid evaluation of yield determination traits may expedite breeding of high-yielding rice. Here, we report a new remote-sensing technique for the evaluation of canopy ecophysiological status under field conditions developed based on simultaneous measurements of sunlit and suddenly shaded canopy temperatures. This technique has the advantage of instantaneous estimation of aerodynamic resistance (r(a)) and canopy diffusive resistance (r(c) without measuring wind velocity. Canopy diffusive conductance (1 / r(c)) estimated by the remote sensing method was closely related to leaf stomatal conductance (g(s)) measured with a portable gas exchange system. This result supported the validity of this new method for quantitative estimation of canopy physiological characteristics. Significant genotypic differences were obtained in canopy-air temperature difference (Tc-Ta), r(c) and 1 / r(c) during the 2-week period preceding full heading for two years, and 1 / r(c) was highly correlated with crop growth rate (CGR), which was closely related to the final yield. These results suggest that 1 / r(c) can be an effective criterion for the selection of high-yielding rice genotypes, and the remote sensing technique proposed here can be a powerful tool for the rapid evaluation of 1 / r(c) under field conditions.
authors.affiliation: Laboratory of Crop Science, Division of Agronomy, Graduate School of Agriculture, Kyoto University, Sakyo, Kyoto 606-8502, Japan. horiet@adm.kais.kyoto-u.ac.jp
authors.forename: Takeshi
authors.initials: T
authors.lastname: Horie
authors.forename: Shoji
authors.initials: S
authors.lastname: Matsuura
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Takai
authors.forename: Kouhei
authors.initials: K
authors.lastname: Kuwasaki
authors.forename: Akihiro
authors.initials: A
authors.lastname: Ohsumi
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Shiraiwa
mesh_terms: D000383:Agriculture / Q000379:methods*; D002245:Carbon Dioxide / Q000378:metabolism; D018556:Crops, Agricultural / Q000235:genetics* / Q000254:growth & development* / Q000502:physiology; D005838:Genotype; D012275:Oryza / Q000235:genetics* / Q000254:growth & development* / Q000502:physiology; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D018526:Plant Transpiration; D013696:Temperature; D014919:Wind
chemical_list: D002245:Carbon Dioxide