Infrared Thermal Imaging for Estimating Crop Canopy Temperature.

Canopy temperature reflects the interaction among plants, soil and atmosphere and has been recognized as an indicator of plant water status. Thermal imaging has been used to study the stomatal behavior of plants under different water conditions. This study investigates the potential use of infrared thermal imaging in calculating crop canopy temperature and determining relationship between canopy temperature and yield. Thermal images were taken from the field of different wheat genotypes under various water regimes in 2011 and 2015 at two locations. Images were processed using IR Crop Stress Image Processor Software to filter out the background soil from thermal image of the wheat plots and to calculate the mean canopy temperature of the selected area in the image. Thermal images data from these studies were analyzed. A strong negative correlation was found between canopy temperature and crop yield across the genotypes indicating that the genotypes with relatively lower canopy temperature around mid-day during grain filling may be connected to higher yield under drought conditions. Canopy temperature of wheat genotypes measured under dryland condition was higher than in irrigated condition and a significant difference in canopy temperature among the genotypes grown under dryland condition was found. The results indicate that canopy temperature can be a good indicator of crop water status and can be used as a selection criterion in identifying drought tolerant genotypes under limited water conditions.

Key words: Thermal imaging, canopy temperature, wheat yield