Aerial canopy temperature differences between fast- and slow-wilting soya bean genotypes

Drought stress limits crop growth and yield in soya bean (Glycine max [L.] Merr.), but there are relatively few tools available to assess the ability of different genotypes to tolerate drought. Aerial infrared image analysis was evaluated as a potential tool for identifying drought tolerance in soya bean. Drought effects were evaluated from late vegetative to mid-reproductive stages of soya bean development in an experiment with ten genotypes including five slow- and five fast-wilting genotypes that were from a population derived from BenningxPI416937. There were two deficit irrigation levels for 2years and one deficit irrigation level for the third year along with a fully irrigated control level. When the canopy was completely closed, relative canopy temperature was determined using an infrared camera taken from an aerial platform 50-75m above the experiment. As water availability decreased, the relative canopy temperature generally increased. Moreover, slow-wilting soya bean genotypes generally had lower canopy temperature compared to fast-wilting genotypes, and grain yield was generally positively associated with cool canopy temperatures. The results indicate that the determination of canopy temperature is a promising tool for rapid characterization of drought-related traits in soya bean.