Use of Canopy Temperatures of Identify Water Conservation in Cotton Germplasm
1987
Hatfield, J. L. | Quisenberry, J. E. | Dilbeck, R. E.
Screening crop germplasm for water conserving traits is difficult under dryland environments because of the variability in soil-water use. Canopy temperatures have been related to crop water stress. This study was designed to evaluate whether cotton (Gossypium hirsutum L.) germplasm differs in canopy temperatures and whether these temperatures could be related to performance under deficit soilwater conditions. Cotton strains (both exotic and commercial) were grown in irrigated and dryland field plots on an Oiton clay loam (fine, mixed, thermic Aridic Paleustoils). The dryland plots were grown under a rainout shelter to exclude any rainfall during the season while the irrigated plots received two irrigations during the measurement period. Canopy temperatures were measured daily between 1330 to 1430 h CST with a hand-held infrared thermometer. Consistent canopy temperature differences occurred among strains grown in the irrigated plots even though the environmental conditions varied. In the dryland plots, canopy temperatures showed significant strain-by-day interactions suggesting that some strains use their available soil water faster than other strains. Calculated nonstressed baselines showed that the strains had a constant slope of −2.00°C kPa⁻¹ and differed only in their intercept. Those strains, which had warmer canopies in the irrigated plots, had the larger biomass in the dryland plots. It is possible to separate cotton germplasm with infrared thermometry.
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