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A field experiment was conducted at New Mexico State University to investigate the effect of seeding rates and ZEBA polymer [starch-g-poly (2-propenamide-co-propenoic acid) potassium salt] seed coating on the germination and establishment of warm- and cool-season grasses, and cool-season blends and mixtures. Grasses were established at recommended and reduced (50% of recommended) seeding rates with coated and uncoated seeds under two irrigation regimes (98% and 56% reference evapotranspiration). With the exception of ‘Bengal’ creeping bentgrass (Agrostis stolonifera), the polymer coating did not improve germination of the turfgrasses tested 22 days after seeding (DAS). However, at the end of the establishment period (92 DAS), plots established with ‘Bengal’, Dunes Mix [mixture of ‘Hardtop’ hard fescue (Festuca longifolia), ‘Baron’ kentucky bluegrass (Poa pratensis), ‘Barok’ sheep fescue (Festuca ovina)], ‘Panama’ bermudagrass (Cynodon dactylon), and Turf Sense™ [mixture of ‘Baronie’ kentucky bluegrass, ‘Barlennium’ perennial ryegrass (Lolium perenne), and ‘Barcampsia’ tufted hairgrass (Deschampsia cespitosa)] achieved greater coverage (based on visual estimations) when coated seed was used compared with uncoated seed. Establishment was greater for ‘Bengal’, Dunes Mix, ‘Panama’, Turf Sense™, and Turf Saver™ [blend of ‘Barlexas II’, ‘Barrington’, and ‘Labarinth’ tall fescue (Festuca arundinacea)] when normal seeding rates were applied compared with reduced seeding rates. ‘Barleria’ crested hairgrass (Koeleria macrantha) plots did not establish, regardless of the treatments applied. Results showed that seed coating has the potential to improve establishment at recommended and reduced seeding rates and can compensate for less favorable conditions such as reduced irrigation, reduced seeding rate, or for a combination of both. At the end of the establishment period, not all grasses achieved coverage greater than 50%. Further research over a longer establishment period is needed to determine if coated seed can be beneficial in achieving full coverage.

Warm-season grasses are not widely accepted in Mediterranean countries because they lose color during the winter months. A study was conducted at the University of Padova (Padova, Italy) to determine whether fall and spring water-soluble carbohydrate (WSC) content in stolons of seeded bermudagrass cultivars (Cynodon dactylon) influenced spring green-up in the first year of establishment. Nine bermudagrass cultivars (La Paloma, Mohawk, NuMex Sahara, Princess 77, Riviera, SR 9554, Barbados, Contessa, and Yukon) were seeded in July 2005, and dry weight and WSC content in stolons were measured in Fall 2005 and again in Spring 2006. The percentage of green cover and days needed to achieve 80% green cover (D80) were regressed against November and March values of stolon dry weight and WSC content to determine if they were good predictors of D80. ‘Yukon’ showed earliest spring green-up by end of April, and ‘Princess 77’ and ‘Riviera’ were slowest, needing 43 to 46 days more than ‘Yukon’ to reach D80. There was a significant inverse relationship between November (r² = 0.57) and March (r² = 0.77) WSC content in stolons and D80 for all nine bermudagrass cultivars. These results suggest that bermudagrass cultivars with high WSC in stolons recover more rapidly from dormancy during establishment than those with low WSC content.

A study was conducted at New Mexico State University in Las Cruces, NM, in 2009 and 2010 to investigate the establishment of five turfgrass species {‘Barrister’ kentucky bluegrass [Poa pratensis L.], ‘Barvado’ tall fescue [Festuca arundinacea Schreb.], ‘Premier II’ perennial ryegrass [Lolium perenne L.], ‘Bargusto’ bermudagrass [Cynodon dactylon (L.) Pers. × Cynodon. transvalensis Burtt-Davy], and ‘Sea Spray’ seashore paspalum [Paspalum vaginatum O. Swartz]} from coated and uncoated seed. The grasses were irrigated at 100% reference evapotranspiration (ET₀) during fall, winter, and spring and at 120% ET₀ during summer with either saline [electrical conductivity (EC) = 2.3 dS·m⁻¹] or potable water (EC = 0.6 dS·m⁻¹). Generally, seed coating did not affect seedling emergence negatively when irrigated with saline water. During fall, perennial ryegrass exhibited fastest emergence under both saline and potable irrigation and bermudagrass was the only grass to show greater emergence when irrigated with saline water. Perennial ryegrass and tall fescue were the fastest to emerge in spring, regardless of seed coating or water quality. Seed coating delayed early establishment (less than 50% coverage) but did not affect days to reach 95% coverage (DAS95). Bermudagrass and seashore paspalum required the most DAS95 when seeded in the fall; however, bermudagrass needed fewest DAS95 when seeded in the spring. All grasses established faster when seeded in spring compared with fall. Fall-seeded perennial ryegrass and kentucky bluegrass required similar DAS95, whereas kentucky bluegrass seeded in spring was slower to reach 95% coverage than perennial ryegrass. Saline water had no effect on establishment when grasses were sown in fall. Surprisingly, grasses established in spring and irrigated with saline water reached 95% coverage 26 days faster than plots irrigated with potable water. Moreover, the growing degree-day model used in this study did not produce similar values for the different air temperatures and irrigation water qualities.

Germination of five turfgrass species [‘Barrister’ kentucky bluegrass (Poa pratensis L.), ‘Barvado’ tall fescue (Festuca arundinacea Schreb.), ‘Premier II’ perennial ryegrass (Lolium perenne L.), ‘Bargusto’ bermudagrass (Cynodon dactylon L. Pers.), and ‘Sea Spray’ seashore paspalum (Paspalum vaginatum O. Swartz)] from coated (ZEBA^® cornstarch coating; Absorbent Technologies Inc., Beaverton, OR) and uncoated seeds was evaluated on both filter paper and agar. Final germination percentage (FGP) and germination rate (GR) were determined at salinity levels of 0.6 (tap water, control), 2.2 (saline groundwater from a local shallow aquifer), and 7.0, 12.5, and 22.5 dS·m⁻¹ [sodium chloride and calcium chloride (1:1, w:w) dissolved in tap water]. Final germination percentage for kentucky bluegrass, perennial ryegrass, and tall fescue was greater in agar at all salinity levels but was unaffected by the medium at any of the salinities except for 7 dS·m⁻¹ for bermudagrass and seashore paspalum. Coated seashore paspalum and coated perennial ryegrass seed exhibited greater germination than uncoated seed at four of the five salinity levels. Seed coating had no effect on FGP of bermudagrass at any salinity level and coated kentucky bluegrass seed showed reduced germination at 0.6 and 7.0 dS·m⁻¹. Final germination percentage for seashore paspalum improved from 22% to 54% at 12.5 dS·m⁻¹ and from 8% to 20% at 22.5 dS·m⁻¹ when coated seed was used instead of uncoated seed. Germination rates were unaffected by salinity levels ranging from 0.6 to 12.5 dS·m⁻¹ and were higher on agar (10%/day) than on paper (8%/day). Our study suggests that the choice of medium can influence the outcome of germination tests and that results can also vary depending on the salinity level tested and whether the seed are coated.