Germinating Perennial Ryegrass Under Saline Conditions.

As water restrictions for golf courses continue to increase, there is a need for identifying turfgrasses that can withstand irrigation from alternative water sources with higher than normal salt concentrations.  The objectives of this study were to determine optimum salinity levels for screening turfgrasses seedlings and to determine seedling salinity tolerance of eight perennial ryegrass cultivars and selections.

          Eight perennial ryegrass entries (Apple GL, KSA, Palmer III, Zoom, Linn, Paragon GLR, ESP, RKS) were evaluated under seven salinity treatments made using equal quantities of NaCl and CaCl₂: Control, 0.25 dSm^-1; 1.0 dS m^-1; 2.0 dS m^-1, 3.0 dS m^-1, 4.0 dS m^-1, 5.0 dS m^-1, and 6.0 dS m^-1.  Treatments were arranged in a complete random design with three replications.  Entries were seeded at a rate of 7.44g m^-2 into a sterilized freehold sandy loam soil.  Nitrogen fertilizer was applied at a rate of 1.49 g/m^-2 at seeding.  Four hundred ml m^-2 of each saline water treatment were applied to each 10 by 10 cm pot using a trigger sprayer to simulate overhead irrigation.  Visual ratings of seedling emergence and percent green were collected and reported as a percentage of the control treatments. Digital image analysis was also used to calculate percent green.

          Significant difference were observed between salinity treatments (across all cultivars) and between cultivars (across all treatments) for percent green and seedling emergence. However in both runs of the experiment there were no differences between cultivars within salinity treatments.  Increased salinity treatments caused a reduction in seedling emergence and visual percent green of all perennial ryegrass tested with 6 ds/M exhibiting a 60%-77% reduction in seedling emergence and a 63%-77% reduction in visual percent green compared to the control.  Linn and Zoom had the highest percent green values across both runs when averaged across all treatments.