title: Methodology for High-Throughput Field Phenotyping of Canopy Temperature Using Airborne Thermography.
abstract: Lower canopy temperature (CT), resulting from increased stomatal conductance, has been associated with increased yield in wheat. Historically, CT has been measured with hand-held infrared thermometers. Using the hand-held CT method on large field trials is problematic, mostly because measurements are confounded by temporal weather changes during the time required to measure all plots. The hand-held CT method is laborious and yet the resulting heritability low, thereby reducing confidence in selection in large scale breeding endeavors. We have developed a reliable and scalable crop phenotyping method for assessing CT in large field experiments. The method involves airborne thermography from a manned helicopter using a radiometrically-calibrated thermal camera. Thermal image data is acquired from large experiments in the order of seconds, thereby enabling simultaneous measurement of CT on potentially 1000s of plots. Effects of temporal weather variation when phenotyping large experiments using hand-held infrared thermometers are therefore reduced. The method is designed for cost-effective and large-scale use by the non-technical user and includes custom-developed software for data processing to obtain CT data on a single-plot basis for analysis. Broad-sense heritability was routinely >0.50, and as high as 0.79, for airborne thermography CT measured near anthesis on a wheat experiment comprising 768 plots of size 2 × 6 m. Image analysis based on the frequency distribution of temperature pixels to remove the possible influence of background soil did not improve broad-sense heritability. Total image acquisition and processing time wasca.25 min and required only one person (excluding the helicopter pilot). The results indicate the potential to phenotype CT on large populations in genetics studies or for selection within a plant breeding program.
authors.affiliation: CSIRO Agriculture and Food Canberra, ACT, Australia.
authors.forename: David M
authors.initials: DM
authors.lastname: Deery
authors.affiliation: CSIRO Agriculture and Food Canberra, ACT, Australia.
authors.forename: Greg J
authors.initials: GJ
authors.lastname: Rebetzke
authors.affiliation: High Resolution Plant Phenomics Centre, Australian Plant Phenomics Facility, CSIRO Agriculture and Food Canberra, ACT, Australia.
authors.forename: Jose A
authors.initials: JA
authors.lastname: Jimenez-Berni
authors.affiliation: CSIRO Agriculture and Food Canberra, ACT, Australia.
authors.forename: Richard A
authors.initials: RA
authors.lastname: James
authors.affiliation: CSIRO Agriculture and Food Canberra, ACT, Australia.
authors.forename: Anthony G
authors.initials: AG
authors.lastname: Condon
authors.affiliation: CSIRO Agriculture and Food Canberra, ACT, Australia.
authors.forename: William D
authors.initials: WD
authors.lastname: Bovill
authors.affiliation: High Resolution Plant Phenomics Centre, Australian Plant Phenomics Facility, CSIRO Agriculture and Food Canberra, ACT, Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Hutchinson
authors.affiliation: High Resolution Plant Phenomics Centre, Australian Plant Phenomics Facility, CSIRO Agriculture and Food Canberra, ACT, Australia.
authors.forename: Jamie
authors.initials: J
authors.lastname: Scarrow
authors.affiliation: CSIRO Information Management and Technology Canberra, ACT, Australia.
authors.forename: Robert
authors.initials: R
authors.lastname: Davy
authors.affiliation: CSIRO Agriculture and FoodCanberra, ACT, Australia; ARC Centre of Excellence for Translational Photosynthesis, Australian National UniversityCanberra, ACT, Australia.
authors.forename: Robert T
authors.initials: RT
authors.lastname: Furbank
keywords: data processing; field experiments; image analysis; pixel histogram analysis; thermal imaging; wheat