ABSTRACT

Recurrent selection for drought and heat tolerance among hybrids of perennial ryegrass (Lolium perenne L.) with meadow fescue (Festuca pratensis Huds.), was used to develop turf-type populations with a marked increase in stress tolerance. Increased tolerance was associated with the presence of an introgression of F. pratensis chromatin on chromosome 3 of L. perenne. To determine if root characteristics were responsible for the improved stress tolerance, a greenhouse study was conducted to compare sister lines of Festulolium both with or without the introgression; the recurrent backcross parent; a representative F. pratensis; and turf-type tall fescue (Festuca arundinacea Schreb.) grown under well-watered conditions in 5.1-cm diam. x 160-cm long tubes containing sand. Two separate 120-day experiments revealed that F. pratensis produced deeper roots, more root biomass, and a higher root:shoot, while the industry standard, F. arundinacea, ranked at or near the lowest value. For the hybrids and ryegrass, the root parameters were intermediate between the 2 fescues, with no statistically significant difference among the 3 lines tested. The results indicate that in the tested Festulolium turf, drought and heat tolerance were not a consequence of increased root depth or root biomass as reported in previous reports for forage-type intergeneric hybrids of ryegrass and fescue.