Greenhouse Screening of Perennial Ryegrass Cultivars for Salinity Tolerance.

Water conservation is a necessary and responsible practice especially in high water using urban landscapes and golf courses.  Turfgrass areas are the perfect environment to use alternative water sources, however, these sources are often high in total dissolved salts and can result in salt stress injury and poor turf quality.  The objectives of this study were to develop a greenhouse screening technique and to identify perennial ryegrass cultivars (Lolium perenne L.) with salinity tolerance.  A greenhouse salt chamber system was developed to simulate field conditions by applying saltwater treatments using an overhead sprinkler system.  Eight clones of each of five perennial ryegrass cultivars (Palmer III, Paragon GLR, Applaud, Brightstar SLT and Nui) were established in tanks containing 100% sand.  The plants were evaluated at four different salt water concentrations for 10 weeks (0, 5, 10 and 15 dS/m) and arranged in a randomized complete block design with three replications.  Clipping weights, plant heights, and percent green ratings were taken weekly.  Root lengths, root weights and shoot weights were taken after the 10 week salinity stress period.  The entire experiment was repeated twice.  Significant differences were observed between salinity treatments.  Percent green ratings across all plants were reduced with increasing salt treatments with the highest salinity treatments causing the most injury to the plants.  Significant differences between perennial ryegrass clones were also observed.  Palmer III clones consistently exhibited the highest percent green ratings across all salinity treatments.  Applaud and Paragon GLR exhibited moderate percent green ratings across all treatments.  Nui exhibited the lowest percent green rating across all treatments. Palmer III maintained relatively higher root weights compared to other turf-type cultivars under increased salinity stress.  Nui had lower percent root weights and shoot weights compared to other cultivars.  These results indicate Palmer III exhibited good salinity tolerance while Nui exhibited poor salinity tolerance compared to the other turf-type perennial ryegrass cultivars evaluated.