Quantifying the Effects of Salinity Stress On Germination of Perennial Ryegrass.

Perennial ryegrass (Lolium perenne L.) is an important cool-season turfgrass species sometimes used for overseeding dormant warm season turfgrasses due to its ability to germinate and establish quickly.  Many golf courses are restricted to using effluent water as an irrigation source which can be high in salts.  High salt concentrations can disrupt germination and growth and development of seedlings.

            Ten perennial ryegrass cultivars (Phenom, Stellar GL, Fiesta 4, Soprano, Zoom, Gator 3, Affirmed, Paragon GLR, Apple GL, SR 4600 ) were evaluated at two salintity treatments: Control (0.5 dSm^-1) which consisted of tap water, and a salinity treatment (10 dSm^-1) made using a dilution of Instant Ocean in tap water.  Three replicates of each cultivar were arranged in a completely random design within each salinity treatment.  Fifty random seeds of each cultivar were placed into 25.8 x 25.8cm  pots filled with topdressing sand.  All pots were submerged into six cm of either tap water or the Instant Ocean salt solution daily for five minutes or until saturated.  Half-strength Hoagland solution was used to provide nutrients in both treatments.   Emerged seedlings were counted daily.  Seedlings were removed 14 days after seeding and root and shoot lengths were measured.  Plants were then separated into roots and shoots and dried at 65°C for 48 hours.  Total germination percentage, germination rate, root length, shoot length, and shoot and root weight data were collected.

            The salinity treatment reduced all measurements collected.  Interestingly, it was found that there was no statistical treatment by cultivar effect in emergence rate indicating that selection for improved germination rate may be conducted under well watered conditions.   Future studies will be conducted to confirm the best selection procedures for improving turfgrass salinity tolerance during germination.