I. Summary

 The major objective of this study was to evaluate well-grown tall fescue cultivars for respective evapotranspiration rates (ET or water use rates) and their associated, above-ground morphological characteristics, such as clipping yield, leaf density, etc. Seven cultivars of tall fescue were seeded into black plastic pots (10-inch diameter x 12-inch deep), established for seven months, and evaluated in the summer of 1994 for ET rates, clipping yields, leaf extension rates, and other leaf characteristics. The cultivars were evaluated under well-watered, field conditions in four, 7-day trials.

 Data from this first-year study showed the following:

1. There were minimal differences in ET rates among the seven cultivars.
2. There were significant differences among the cultivars for important agronomic characteristics, such as clipping yield (46% difference between the highest and lowest cultivar)and leaf density (52% difference between highest and lowest cultivar).
3. ET rate was not significantly associated with any other measurement, while clipping yield was significantly (+) associated to leaf extension rate, and significantly (-) associated to leaf density.
4. RF 1,Shortcut (Marathon III) , and Tomahawk produced the lowest clipping yields and also had the highest combination of slow leaf extension rate and high leaf density.

II. Materials and Methods
 Seven cultivars of tall fescue were seeded into lysimeters for seven months, and then evaluated in the summer of 1994 for their ET rates, clipping yields, and above-ground morphological traits (Tables 1 to 6). The above-ground morphological diversity within this seven-cultivar collection was fairly representative of the morphological diversity observed within tall fescue cultivars utilized for turfgrass purposes.

 Well-established turfgrass grown under a management program reflective of the production of high quality tall fescue was evaluated in this study (Tables 1 and 2).

 ET rates were measured by the water-balance method in four separate trials (Tables 2, 3 and 4).Note that ET rates were measured when the tall fescue lysimeters were placed under field conditions, were well watered, and were in the last three days of a seven-day mowing cycle (Tables 3 and 4). Environmental conditions during the four trials were recorded by a CIMIS station located at the UCR Turfgrass Research Project (Table 5).

 Clipping yields and leaf extension rates also were measured during each ET rate trial (Tables 4 and 6). Leaf density, length, and width were measured between the third and fourth ET rate trials (Tables 4 and 6). Visual turfgrass quality was measured during and after the study (Table 6).