The objective of this study was to characterize and compare the transpiration
response of 19 warm-season turfgrass genotypes and cultivars in five species during soil drying and wellwatered
conditions in the greenhouse. The species included in the study were: Zoysia japonica (Steud),
Zoysia matrella L., common bermudagrass (Cynodon dactylon L. Pers. var. dactylon), African bermudagrass
(Cynodon transvaalensis Burtt-Davy), hybrid bermudagrass (C. dactylon L. var. dactylon
×
C. translvaalensis
Burtt-Davy) and St. Augustinegrass [Stenotaphrum secundatum (Walter) Kuntze]. They were evaluated for
evapotranspiration rate (ET) and the sensitivity of transpiration to soil drying which was indicated by a
break point of the fraction transpirable soil water (FTSW). The range of break point during dry down was
from 0.25 to 0.41, and genotypes within species had different ET when well-watered (ETck). Break point
values were not correlated with the number of days to the endpoint, where ET declined below 10% of the
control. Instead, the number of days to endpoint was negatively correlated with ETck (−0.59, P
≤
0.01).
Thus, these results found significant variability in turfgrass break point and ETck that could contribute to
water conservation, and a better understanding of drought responses in warm season turfgrasses.