Screening Sorghum Genotypes for Canopy Temperature Using Field Based Infra-Red (IR) Sensors.

One of the key approaches that have been used to enhance crop yields during late-season water deficit conditions is conservation of soil. Studies using soybean and sorghum have shown that there are some genotypes that will limit transpiration rate (TR) at a constant, maximum rate under high evaporative conditions and therefore use water conservatively. When this happens, canopy temperature will tend to be higher as the plant is not pulling up a lot of water from the soil to cool its leaves.  A simulation study with sorghum to examine the putative benefits of restricted transpiration rate during high vapor pressure deficit (VPD) conditions resulted in average yield gains with the largest benefit seen in dry, low yielding seasons. Plant canopy temperature has been used in many studies of to explore plant/environment interactions. A key role of transpiration in plants is leaf cooling. Canopy temperature changes relative to air temperature is an indication of the capability of transpiration in cooling plant leaves under a demanding environmental load. Continuous measurement of plant canopy temperature can be used to provide a better understanding of the physiological environmental processes that affect canopy temperatures and in turn water stress. The objective of this experiment is to evaluate variability in canopy temperature of some selected sorghum genotypes under field conditions over periods of the growing season. Genotypes will be grown out in the field and when canopies are fully established IR sensors will be mounted to monitor canopy temperature, air temperature and relative humidity over periods of time. Data collected will be used to evaluate correlations between canopy temperature and physiological and growth traits, yield and yield components