Freshwater resources for turfgrass irrigation are becoming limited. Hence, the development of drought tolerant turf cultivars will be of great value to turf managers. The objective of the following research was to evaluate the field drought tolerance of turf‐type tall fescue (Festuca arundinacea Schreb.) entries that were selected based either on high root/shoot ratio under greenhouse conditions or under severe drought stress conditions in the field. Twelve tall fescue entries (two selected by root/shoot ratio, two selected by screening field drought tolerance, the four parents, and four standard controls) were established under a rain‐out shelter, and their green turf coverage was evaluated during drought stress (irrigation withheld) and drought recovery (irrigation reapplied) events in 2003 and 2004. In both years, entries selected for high root/shoot ratio demonstrated significantly improved drought tolerance compared to their parents, whereas improved drought tolerance for field‐selected entries was less consistent. Turf green‐up following drought conditions was correlated to the drought tolerance of each entry, in that those cultivars that were the most drought tolerant were also the first to green up on rewatering. These results validate that selecting germplasm based on high root/shoot ratio in the greenhouse is a viable method for improving the field drought tolerance of turf‐type tall fescue.

As freshwater resources for turfgrass irrigation become more limited, the development of drought‐tolerant turf cultivars will be of great value to turf managers. The objective of the following research was to evaluate the field drought tolerance of Kentucky bluegrass (Poa pratensis L.) cultivars and compare their drought tolerance to rooting capacity. Fifty bluegrass entries were established in the field in Albany, OR and evaluated during drought stress (irrigation withheld) events in 2005 and 2006. Drought tolerance was measured, using digital image analysis, as the number of days until a cultivar reached 50% green tissue. In both years, there was a wide range of cultivar responses to drought, with some cultivars losing 50% green tissue 23 d after irrigation was withheld, while others maintained 50% green tissue up to 45 d after irrigation was withheld. Several cultivars, including Mallard, Moonlight, Prosperity, SR2284, Brilliant, and Diva, demonstrated significantly better drought tolerance than other cultivars. Twenty of the cultivars tested under field conditions were also screened for shoot and root growth in a greenhouse study. There was no correlation between shoot growth, root growth, or root:shoot ratios when compared to drought responses in the field. These results demonstrate that there is wide variability in drought tolerance of bluegrasses but factors other than rooting capacity appear to be responsible for those differences.

The identification and selection of germplasm with improved drought tolerance will play an important role in developing turfs with better performance and persistence during drought stress periods. The objectives of the study were to: (i) determine the feasibility of simultaneously selecting plants with low‐shoot‐to‐high‐root ratios and increased root mass in lower sand profiles using flexible tubes under greenhouse conditions, and (ii) determine gain from two cycles of selection for increased root production within the flexible tubes. Seeds from two populations of tall fescue (Festuca arundinacea Schreb.) and perennial ryegrass (Lolium perenne L.) were germinated in 29.5% (−1.4 MPa osmotic potential) and 28.5% (−1.2 MPa osmotic potential) polyethylene glycol (PEG), respectively, for each cycle of selection. The most vigorous seedlings were transferred to flexible root tubes, 63.5 cm long filled with silica sand, to evaluate for deep root production in the greenhouse. Clippings were collected weekly and root weights were determined after approximately 8 to 12 wk of growth in the flexible root tubes. The top 2 to 4% of the populations were selected for the following characteristics: clipping weights at or below the mean of the population and root weights (in the bottom 30 cm) at least 1 SD above the mean of the population for the turf‐type tall fescue and perennial ryegrass populations. After two cycles of selection for increased root mass in the lower 30 cm, gain from selection was approximately 41% in a narrow population and 81% in a broad population of tall fescue and 130% in a turf‐type and 367% in a forage‐type perennial ryegrass. This technique should be very successful in developing turfgrasses with improved rooting characteristics.

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The development of drought‐tolerant turf cultivars can have a positive impact on future water resources. The objective of the following research was to evaluate the field drought tolerance of nine Kentucky bluegrass (Poa pratensis L.) cultivars and eighteen hybrid bluegrass (primarily P. pratensis × P. arachnifera Torr.) cultivars. The bluegrass entries were established in the field in Albany, OR, and evaluated under drought stress in the summer of 2006 and 2007. Drought tolerance and recovery following drought were measured using digital image analysis and were defined as the number of days until a cultivar reached 50% green tissue. Several Kentucky bluegrass cultivars, including Mallard, Bluestone, and Arrow, demonstrated significantly better drought tolerance than other Kentucky bluegrass and hybrid bluegrass cultivars. One hybrid bluegrass cultivar, Longhorn, and several experimental hybrids, had excellent drought tolerance in this trial. However, many of the hybrids tested in this trial did not have superior drought tolerance characteristics compared to the Kentucky bluegrasses tested. These results demonstrate that there is wide variability in drought tolerance among both Kentucky bluegrass and hybrid bluegrass and the broad screening of this genetic material under limited water can provide turfgrass managers with selections that can ultimately conserve water. In addition, these results demonstrate that there are no clear differences in drought tolerance between hybrid bluegrasses and Kentucky bluegrass.