Canopy Temperatures, Water Use, and Water Use Efficiency of Corn Genotypes
1981
Mtui, T. A. | Kanemasu, E. T. | Wassom, C.
It is desirable to describe and characterize physiological properties of corn (Zea mays L.) genotypes that will permit a basis for selecting genotypes. The objective of this field study was to compare two hybrids (Mo17 ✕ B73, A619 ✕ A632) and their respective inbred parents under irrigated and nonirrigated conditions. Measurements of canopy temperature, stomatal diffusive resistance, xylem water potential, leaf area index, ear dry weight, and grain yield were determined. Water use was determined from neutron moderation measurements of the soil-water profile. The soil was a fine silty, mixed mesic, Pachic Haplustoll that holds approximately 250 mm of plant available water. Hybrids had higher grain yield, water use, and water use efficiency than the inbred parents under both irrigated and nonirrigated conditions. Estimates of water use by both hybrids and inbreds were greater for irrigated than for nonirrigated treatments. Early ear dry weight appeared to be an indicator of final ear weight, and in this particular study, was an indicator of final grain weight. Canopy temperatures were cooler for hybrids than for the inbreds which is consistent with greater water use by the hybrids. Stomatal resistance and xylem water potential were not significantly different among genotypes.
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