Evapotranspiration Rates and Growth Characteristics of Ten St. Augustinegrass Genotypes

Abstract

The primary objective of this research was to determine the evapotranspiration (ET) rates of 10 well-watered St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] genotypes under field conditions and in a controlled-environment chamber with a high evaporative potential. A secondary objective was to correlate ET rate to leaf extension rate, shoot density, and abaxial and adaxial leaf blade stomatal densities. Overall ET rates among genotypes were not significantly different in the field study, but they were significantly different under the higher evaporative potential of the chamber study. ET rates under field conditions were not correlated to ET rates under chamber conditions. ET rates were not correlated to leaf extension rates in the field or chamber. ET rates in the chamber were correlated neither with shoot nor with stomatal densities. Overall ET rates in the field study were not correlated to stomatal densities, but were correlated to shoot density (r = 0.77).