title: Predawn respiration rates during flowering are highly predictive of yield response in Gossypium hirsutum when yield variability is water-induced.
abstract: Respiratory carbon evolution by leaves under abiotic stress is implicated as a major limitation to crop productivity; however, respiration rates of fully expanded leaves are positively associated with plant growth rates. Given the substantial sensitivity of plant growth to drought, it was hypothesized that predawn respiration rates (RPD) would be (1) more sensitive to drought than photosynthetic processes and (2) highly predictive of water-induced yield variability in Gossypium hirsutum. Two studies (at Tifton and Camilla Georgia) addressed these hypotheses. At Tifton, drought was imposed beginning at the onset of flowering (first flower) and continuing for three weeks (peak bloom) followed by a recovery period, and predawn water potential (ΨPD), RPD, net photosynthesis (AN) and maximum quantum yield of photosystem II (Fv/Fm) were measured throughout the study period. At Camilla, plants were exposed to five different irrigation regimes throughout the growing season, and average ΨPD and RPD were determined between first flower and peak bloom for all treatments. For both sites, fiber yield was assessed at crop maturity. The relationships between ΨPD, RPD and yield were assessed via non-linear regression. It was concluded for field-grown G. hirsutum that (1) RPD is exceptionally sensitive to progressive drought (more so than AN or Fv/Fm) and (2) average RPD from first flower to peak bloom is highly predictive of water-induced yield variability.
authors.affiliation: Department of Crop and Soil Sciences, University of Georgia, 115 Coastal Way, Tifton, GA 31794, USA. Electronic address: jlsnider@uga.edu.
authors.forename: John L
authors.initials: JL
authors.lastname: Snider
authors.affiliation: Department of Crop and Soil Sciences, University of Georgia, 115 Coastal Way, Tifton, GA 31794, USA.
authors.forename: Daryl R
authors.initials: DR
authors.lastname: Chastain
authors.affiliation: Department of Crop and Soil Sciences, University of Georgia, 115 Coastal Way, Tifton, GA 31794, USA.
authors.forename: Calvin D
authors.initials: CD
authors.lastname: Meeks
authors.affiliation: Department of Crop Science, North Carolina State University, Upper Coastal Plains Research Station, 2811 Nobles Mill Pond Road, Rocky Mount, NC 27801, USA.
authors.forename: Guy D
authors.initials: GD
authors.lastname: Collins
authors.affiliation: USDA, Agricultural Research Service, National Peanut Research Laboratory, 1011 Forrester Drive, Dawson, GA 39842, USA.
authors.forename: Ronald B
authors.initials: RB
authors.lastname: Sorensen
authors.affiliation: Department of Crop and Soil Sciences, University of Georgia, 115 Coastal Way, Tifton, GA 31794, USA.
authors.forename: Seth A
authors.initials: SA
authors.lastname: Byrd
authors.affiliation: Department of Crop and Soil Sciences, University of Georgia, Stripling Irrigation Research Park, Camilla, GA 31730, USA.
authors.forename: Calvin D
authors.initials: CD
authors.lastname: Perry
mesh_terms: D055864:Droughts; D035264:Flowers / Q000254:growth & development; D005845:Georgia; D003368:Gossypium / Q000502:physiology*; D018515:Plant Leaves / Q000502:physiology; D011897:Random Allocation; D012621:Seasons; D014867:Water / Q000502:physiology*
chemical_list: D014867:Water
keywords: Drought; Gossypium hirsutum; Predawn respiration; Water potential; Yield