Drought tolerance of tall fescue populations selected for high root/shoot ratios and summer survival

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.