Performance of Perennial Ryegrass Cultivars in Michigan (E3040)
Perennial ryegrass adapts well to cool, moist environments characterized by mild summers and winters with no extreme temperatures. Perennial ryegrass is the cool-season grass most sensitive to temperature extremes and drought.
Performance of Perennial Ryegrass Cultivars in Michigan, 2005-06
Perennial ryegrass adapts well to cool, moist environments characterized by mild summers and winters with no extreme temperatures. Perennial ryegrass is the cool-season grass most sensitive to temperature extremes and drought. It will become dormant during hot summers and be severely injured by harsh winters. In some states, such as Minnesota, it is considered a short-lived perennial, usually surviving only one to two winters, depending on snow cover duration. Traditionally, perennial ryegrass is used as a nurse or cover grass for turfgrass mixtures in both the temperate and transition climatic zones because of its rapid germination rate and vigorous seedling growth. Currently, it has been used extensively in highly trafficked sport fields in mixtures with Kentucky bluegrass. It is also used often for overseeding in football and soccer fields during the fall to provide rapid turfgrass cover on thin areas. Overseeding with perennial ryegrass is a technique used to extend or improve winter play by adding grass covers to dormant or semi-dormant warm-season grass, such as bermudagrass in the southern states.
This species is best suited to well-drained soils. It requires 3 to 5 pounds of nitrogen (N) per 1,000 square feet per growing season. Thatch development is minimal with this species, which has a suggested mowing height range between 2 and 3 inches, or higher in dry summers. Perennial ryegrass seeds germinate very quickly — in about 7 days under ideal conditions — and will establish extensive root systems during the first year of growth. To obtain a dense, fine-textured turf, perennial ryegrass should be seeded at 6 to 8 pounds of seed per 1,000 square feet. Seeding perennial ryegrass in August is highly recommended for Michigan to allow grass to develop the deep root system needed to survive the cold winter. Planting perennial ryegrass late in the fall may not allow it to develop the fully established root system that it needs before winter to avoid winter diseases and ice damage. Perennial ryegrass seeded in the summer tends to undergo excessive heat and drought stress and is susceptible to seedling diseases.
The most serious diseases affecting perennial ryegrass are the snow molds, brown patch and red thread. Snow mold disease occurs mostly in the northern United States during winters with prolonged snow cover. Brown patch is more common in the southeastern United States during the hot, humid months of summer. It is especially severe when the turf is heavily fertilized with N fertilizer. Other damaging diseases of perennial ryegrass are net blotch, rust and pythium blight.
Several perennial ryegrass cultivars show endophyteenhanced resistance to various leaf- and stem-feeding insects. Endophytes are beneficial fungi that reside within the seed and grow in the stem and leaf sheath but not in the root or leaf blades. They do not harm the host plant, people or pets that occasionally eat the grass. However, endophyte-containing perennial ryegrass may be detrimental to animals that consume large quantities of the grass as a significant part of their nutritional requirements (e.g., cows, horses and/or sheep). Endophytes produce chemicals called alkaloids that protect the plants from insects and nematodes by discouraging leaf- and stem-feeding insects from destroying the plant.
Two National Turfgrass Evaluation Program (NTEP) perennial ryegrass tests were established in September 2004 at the Hancock Research Center at Michigan State University, one for quality evaluation and the other for wear tolerance evaluation. Each test included 160 commercial cultivars (see Table 1). Each cultivar was seeded in 4- by 6-foot plots at a rate of 4.4 pounds of seed per 1,000 square feet. The entire test area received full sunlight, was mowed at 3 inches with a reel mower and was fertilized twice each year of the test (spring and fall) with 1 pound of N per 1,000 square feet per application. The tests were irrigated whenever necessary to prevent wilting. The plots were visually evaluated once per month during the growing season for turfgrass quality and other parameters. “Quality” indicates the overall appearance of the turf and can incorporate several components, including density, texture, uniformity, color, and freedom from disease and insect damage. Quality was rated using a scale of 1 to 9, where 9 = highest quality. The average quality rating of entries for 2005 and 2006 are listed in the table. For comparison, average turfgrass quality of perennial ryegrass grown at nine locations in the United States (Illinois, Indiana, Minnesota, Iowa, Nebraska, North Dakota, South Dakota and Wisconsin) is included in the table. Turfgrass wear tolerance of perennial ryegrass was included also (see Table 1). Simulated traffic was applied across plots with the Brinkman traffic simulator. Traffic was applied from August to November (12 weeks). The trial received 10 passes per week. Traffic tolerance is the combination of wear and compaction stress that occurs whenever turf is exposed to foot or vehicular traffic. Traffic tolerance is a visual estimate using a 1 to 9 rating scale, with 1 being no tolerance or 100 percent injury and 9 being complete tolerance or no injury.
Differences between two cultivars are statistically significant only if the LSD value listed on the table is exceeded by the numerical differences between two cultivars. All tall fescue cultivars listed in Table 1 are significantly different from ‘Linn’. Significant differences in turfgrass quality were found among perennial ryegrass cultivars in this test during 2005 and 2006. In spite of differences in growing conditions between 2005 and 2006, the average turfgrass quality of some improved cultivars varied little between seasons. The entries showing the best seasonal average quality over the two-year test period are listed in Table 1. For more information, visit http://www.ntep.org under Michigan State University data.