Warm-season Turfgrass Species Research Articles

Establishment and Turf Qualities of Warm-season Turfgrasses in the Mediterranean Region

Warm-season turfgrasses are grown throughout the warm humid, sub-humid, and semiarid regions. The objective of this study was to determine the adaptation of six warm-season turfgrass species and several of their cultivars to Mediterranean growing conditions of Turkey by evaluating turfgrass establishment rate, quality, color, and percentage of turfgrass cover. Information of this nature is lacking and would be helpful to turfgrass managers and advisers working in the region. A study was conducted over a 2-year period in two locations of the Mediterranean region of Turkey. The warm-season turfgrass species studied were bermudagrass (Cynodon dactylon), buffalograss (Buchloë dactyloides), zoysiagrass (Zoysia japonica), bahiagrass (Paspalum notatum), seashore paspalum (Paspalum vaginatum), and centipedegrass (Eremochloa ophiurioides). Tall fescue (Festuca arundinacea) was included as a cool-season turfgrass species for comparison. Twenty cultivars belonging to these species were evaluated for their establishment, turfgrass color and quality, spring green-up, and fall color retention. Bermudagrass, bahiagrass, and seashore paspalum established 95% or better coverage at 1095 growing degree days [GDD (5 °C base temperature)], buffalograss and centipedegrass at 1436 GDD, and ‘Zenith’ and ‘Companion’ Zoysiagrass had 90% and 84% coverage at Antalya after accumulating 2031 GDD. ‘Sea Spray’ seashore paspalum; ‘SWI-1044’, ‘SWI-1045’, ‘Princess 77’, and ‘Riviera’ bermudagrass; ‘Cody’ buffalograss; and ‘Zenith’ zoysiagrass exhibited acceptable turfgrass quality for 7 months throughout the growing season. ‘Argentine’ and ‘Pensacola’ bahiagrass; ‘Sea Spray’ seashore paspalum; and ‘SWI-1044’ and ‘SWI-1045’ bermudagrass extended their growing season by retaining their green color 15 days or longer than the rest of the warm-season cultivars and/or species in the fall. The warm-season species stayed fully dormant throughout January and February. Zoysiagrass and buffalograss cultivars showed early spring green-up compared to the other warm-season species studied. Results from this study support the use of warm-season turfgrass species in this Mediterranean region, especially when heat stress and water limitations exist. Tall fescue did not survive summer heat stress necessitating reseeding in fall.

Surface Applications of Dazomet Provide Nonselective Control of Seashore Paspalum (Paspalum vaginatum) Turf

Herbicide applications prior to turf renovation often fail to provide complete control of perennial warm-season turfgrass species like seashore paspalum. Surface applications of dazomet at 506 kg/ha provided > 90% POST control of ‘SeaDwarf’ seashore paspalum turf in 2008. Although applications of glyphosate at 5.6 kg/ha or fluazifop-P-butyl at 0.42 kg/ha induced significant injury, these treatments provided < 40% POST control of SeaDwarf seashore paspalum turf 10 wk after initial treatment (WAIT) in 2008. A similar response was noted following applications of glyphosate plus fluazifop-P-butyl at rates of 5.6 kg/ha and 0.42 kg/ha, respectively. POST control following applications of glyphosate at 5.6 kg/ha plus fluazifop-P-butyl at 0.42 kg/ha, prior to applying dazomet at 506 kg/ha, was not different from that which was observed following applications of dazomet alone at 506 kg/ha. These data suggest that granular applications of dazomet alone, at 506 kg/ha, can be used to provide effective control of SeaDwarf seashore paspalum prior to renovation.

Turf Tolerance and Virginia Buttonweed (Diodia virginiana) Control with Fluroxypyr as Influenced by the Synergist Diflufenzopyr

Virginia buttonweed control in warm-season turfgrass species requires high application rates and/or repeated applications of herbicides (or both) with an auxin-type mode of action. These treatments often lead to unacceptable turfgrass injury. Diflufenzopyr functions as a synergist with auxin-type herbicides, and it has been suggested that it may do the same when combined with pyridine herbicides such as fluroxypyr. The objective of this field and laboratory research was to determine whether Virginia buttonweed control could be improved with admixtures of fluroxypyr and diflufenzopyr without unacceptable turf injury. Treatments consisted of fluroxypyr applied alone at 140 and 280 g ae/ha, diflufenzopyr alone at 70 and 140 g/ha, and all possible two-way admixtures. Treatments were applied to a hybrid bluegrass ‘Thermal blue’ infested with Virginia buttonweed. Sod of centipedegrass ‘common’, hybrid bermudagrass ‘Tifway’, hybrid zoysiagrass ‘Emerald’, and St. Augustinegrass ‘Raleigh’, which had been previously established in pots, were treated simultaneously and returned to a greenhouse. Fluroxypyr plus diflufenzopyr at 280 and 70 g/ha, respectively, controlled Virginia buttonweed nearly 40% more than fluroxypyr alone. Turfgrass injury was species-dependent, and was generally either equivalent to or less than that obtained with fluroxypyr alone. Radiotracer studies established that, depending upon the turfgrass species, fluroxypyr absorption was either not influenced or reduced by the addition of diflufenzopyr. Neither root nor foliar absorption of fluroxypyr by Virginia buttonweed was influenced by diflufenzopyr. Translocation of foliar-absorbed fluroxypyr was reduced, but translocation of root-absorbed fluroxypyr was increased by diflufenzopyr. The diflufenzopyr-induced synergism may indicate that a significant portion of the applied fluroxypyr was absorbed by roots or by other subsoil tissues, or both.

Warm-Season Turfgrass Response to Fertilizer Rates and Sources

The objectives of this study were to evaluate effects of natural organic and inorganic fertilizers on various warm-season turfgrass species and to determine if lower rates of natural organic products would provide adequate turfgrass response. Studies were conducted in 2000 and 2001 in two locations in Florida on St. Augustinegrass (Stenotaphrum secundatumWalt. Kuntze) and bermudagrass (Cynodon dactylon × C. transvaalensisBurtt-Davy) cultivars. Each fertilizer product was applied at a low and a high rate throughout the growing season at rates consistent with current University of Florida recommendations for best turfgrass performance and response. In general, highest visual ratings for quality, color, and density were obtained with the higher rate of nitrogen (N), regardless of source, although the low rate of the 27N-1.3P-3.3K fertilizer produced ratings equal to the higher (N) rates from other sources in St. Augustinegrass. Trends were similar for spectral reflectance values, in that best results generally occurred in response to higher N rate, with the exception of the 27N-1.3P-3.3K fertilizer at the lower rate. From the results of this research, it appears that the higher N rate produces better turfgrass responses, regardless of fertilizer source.

Application of Sequence-related Amplified Polymorphism Markers for Characterization of Turfgrass Species

A simple marker technique called sequence-related amplified polymorphism (SRAP) provides a useful tool for estimation of genetic diversity and phenetic relationships in natural and domesticated populations. Previous studies and our initial screen showed SRAP is highly polymorphic and more informative when compared to AFLP, RAPD and SSR markers. In this study, applicability of the SRAP markers to obtain an overview of genetic diversity and phenetic relationships present among cool-season (C3) and warm-season (C4) turfgrass species and their relationship with other Gramineae species were tested. Phenetic trees based on genetic similarities (UPGMA, N-J) were consistent with known taxonomic relationships. In some cases, well-supported relationships as well as evidence by genetic reticulation could be inferred. There was widespread genetic variation among C3 and C4 turfgrass species. In Dice based cophenetic matrix, genetic similarities among all species studied ranged from 0.08 to 0.94, whereas in Jaccard based cophenetic matrix, genetic similarities ranged from 0.05 to 0.85. C3 and C4 species were clearly distinguishable and a close relationship between italian ryegrass and tall fescue were obtained based on SRAP. Genome structures of turfgrasses are comparable to other Gramineae species. This research indicates that the SRAP markers are useful for estimating genetic relationships in a wide range of turfgrass species. The SRAP markers identified in this study can provide a useful reference for future turfgrass breeding efforts.

First Report of Gaeumannomyces graminis var. graminis on Seashore Paspalum in the United States.

Gaeumannomyces graminis var. graminis is an ectotrophic, root-infecting fungus found on some warm-season turfgrass species (1). A sample of seashore paspalum (Paspalum vaginatum) exhibiting rotted roots and stolons was taken from dying patches of turf in a home lawn in Hernando County, FL, and submitted to the Florida Extension Plant Disease Clinic, Gainesville, in October 2001. The lawn had been established within the previous year. Strongly lobed hyphopodia typical of G. graminis var. graminis (3,4) were present on diseased roots and stolons, and no other fungal plant pathogens were detected in the sample. Diseased roots and stolons with lobed hyphopodia were surface-sterilized and placed on one-quarter-strength potato dextrose agar (PDA) amended with rifampicin and streptomycin. One isolate produced structures characteristic of G. graminis var. graminis (3,4), including dark, strongly lobed hyphopodia, and perithecia and ascospores in PDA after incubation. The isolate (PDC 2965) was grown on a sterile ryegrass seed substrate at 25°C for 4 weeks to produce inoculum (2). The isolate was used to inoculate pots of 'Sea Isle 1' seashore paspalum grown in sterile soil from sprigs. An inoculum layer, 1 to 2 cm deep, was placed 2 to 4 cm below each sprig and covered with an overlay of sterile soil prior to sprigging (2). Following 4 weeks of plant growth in a greenhouse, dark, necrotic lesions appeared on leaf bases. Very dark lesions developed on roots, and brown runner hyphae and strongly lobed hyphopodia were observed on root and shoot tissues. Selected pieces of symptomatic root and shoot tissue were surface-sterilized and placed on PDA. One week later, dark mycelia and deeply lobed hyphopodia were observed growing from roots and shoots on the PDA. After 1 month, black, flask-shaped perithecia, 156 to 234 μm in body width, developed in cultures. Hyaline, filiform, septate ascospores ranged from 75 to 100 μm (mean = 89 μm; n = 250) long and were approximately 2.5 μm wide. Hyphopodia, perithecia, and ascospores were characteristic of G. graminis var. graminis (3,4). To our knowledge, this is the first report of take-all root rot disease due to G. graminis var. graminis on seashore paspalum in the United States.

144 The Effect of Water Stress on Growth of Several Warm-season Turfgrass Species

Four warm-season grass species [common carpetgrass (Axonopus affinis Chase), common bermudagrass (Cynodon dactylon [L.] Pers.), St. Augustinegrass (Stenophrum secondatum Walt. Kuntze.), and zoysiagrass (Zoysia japonica Steud.)] were established in containers filled with an Olivia silt loam soil for 12 weeks. Grasses were maintained weekly at 5 cm prior to the start of the experiment. Water stress treatments consisted of a control (field capacity), waterlogged, and flooded treatments. Waterlogging and flood treatments were imposed for a period of 90 days. The effects of water stress was dependent on grass species. Bermudagrass vegetative growth and turf quality were significantly reduced when flooded. Carpetgrass, St. Augustingrass, and zoysiagrass quality and vegetative growth were also reduced by flooding. St. Augustinegrass and zoysiagrass root dry weight was significantly decreased. Zoysiagrass plants did not survive 90 days of flooding. Leaf tissue analysis for common carpetgrass, common bermudagrass, St. Augustinegrass, and zoysiagrass indicated that plants subjected to waterlogging and flooding had significantly elevated Zn concentrations.

Somatic embryogenesis and plant regeneration of turf-type bermudagrass: Effect of 6-benzyladenine in callus induction medium

In order to optimize tissue culture conditions for bermudagrass, an important warm-season turfgrass species, tissue culture responses of young inflorescences of a hybrid bermudagrass cultivar `Tifgreen' (Cynodon dactylon×Cynodon transvaalensis) and a common bermudagrass cultivar `Savannah' (Cynodon dactylon) were investigated. When cultured on Murashige and Skoog medium with 4.52 to 13.57 μM (1–3 mg l-1) 2,4-D, young inflorescence segments yielded non-embryogenic calli which were unorganized and had loosely associated, long tubular cells on the surface. However, inclusion of 6-benzyladenine (BA) in callus induction medium at a level of 0.044 μM (0.01 mg l-1) induced formation of a compact, nodular embryogenic structure on approximately 20% of the calli. Calli with such a compact embryogenic structure were highly regenerable. When young inflorescences smaller than 0.75 cm were cultured, the embryogenic structure yielded green plantlets with regeneration rates of 79.5% and 83.3%, respectively for the two cultivars. All 96 plants regenerated from calli induced in the BA-containing medium were green and morphologically normal. The embryogenic nature of the compact structure was confirmed by scanning electron microscopy.

Phytotoxicity Evaluation of an Insecticidal Soap and Horticultural Oil on Six Turfgrass Species

Phytotoxic effects of a insecticidal soap (Safer Insecticide Concentrate®) and petroleum-based horticultural oil (Sunspray Ultra-Fine Spray Oil®) were evaluated on four cool-season and two warm-season turfgrass species under cool and moist, and hot and dry environmental conditions. Ambient temperature, relative humidity, and water deficit level of the turfgrass had little observed effect on levels of phytotoxicity. Little or no foliar injury was observed under any environmental conditions following application of insecticidal soap or 1% and 3% horticultural oil on any turfgrass species. In most instances 5% horticultural oil initially caused slight to moderate foliar discoloration, whereas 10% horticultural oil resulted in moderate to substantial foliar discoloration depending on the turfgrass species. Zoysiagrass and creeping bentgrass were the most susceptible species to higher concentrations of horticultural oil. Phytotoxicity was relatively brief even in these more susceptible grasses, however, and there was no evidence of long-term injury to any turfgrass species resulting from any treatment under the two sets of environmental conditions investigated in this study.

EVALUATION OF SELECTED WARM-SEASON TURFGRASS SPECIES GROWN IN RIYADH REGION OF SAUDI ARABIA.

An investigation was conducted to evaluate the growth and adaptability of ten selected warm-season turfgrass species under the environmental condition of Riyadh Region, Saudi Arabia. The establishment rate, yield fresh weight and quality assessments, as evaluation parameters, showed that there were significant differences among these various turfgrass species. Adalyd seashore paspalum and Tifgreen bermudagrass showed the best adaptation, if properly managed. On the other hand, Tifway bermudagrass and Variegata St. Augustinegrass were poorly adapted. Although Egyptian crabgrass showed better growth and good quality, its use may be limited due to its low cold tolerance. Moreover, there were some observations that may limit the use of other turfgrasses, such as the cold stress effect on the common bermudagrass, the very low establishment rate of Korean velvetgrass and the vertical growth habit and low density cf local bermudagrass.

Evapotranspiration and Leaf Extension Rates of 24 Well-watered, Turf-type Cynodon Genotypes

Cultivar selection is one method used for the conservation of irrigation water. The primary objective of this research was to evaluate the evapotranspiration (ET) rates of 24 well-watered, turf-type bermudagrass (Cynodon spp.) genotypes under field conditions and established on a fritted clay root zone contained in plastic minilysimeter pots. A secondary objective was to correlate ET rate to leaf extension rate, a potential rapidly assessed predictor of the amount of leaf surface area present for ET. ET rates were determined by the water-balance method. Both the overall ET and leaf extension rate differed significantly among genotypes. ET rates were not correlated with leaf extension rates in individual years. Our data indicated a potential for water savings based on bermudagrass cultivar selection that was similar to the reported potential water savings based on warm-season turfgrass species selection.

Classification of C3 and C4 Turfgrass Species Based on CO2 Compensation Concentration and Leaf Anatomy1

Abstract Leaf anatomy and CO2 compensation concentration (Γ) were used to determine the carbon fixation pathway for 10 cool season and 5 warm season turfgrass species. Turfgrasses of the subfamily Festucoideae were representative of C3 plants. Turfgrass species of the subfamily Panicoideae and Eragrostoidea were representative of C4 plants. Turfgrasses classified traditionally as cool season or warm season species correlated with C3 and C4 plant types, respectively. Both techniques of C3 and C4 classification proved equally reliable in this study, however, the utilization of Kranz leaf anatomy required less preparation.

Cold Hardening and Carbohydrate Composition of Meyer Zoysia1

AbstractThere are few reports on cold hardening in warmseason turfgrass species. The purpose of our study was to measure changes in cold hardiness and carbohydrate composition of Zoysia japonica Steud ‘Meyer’ turfgrass during fall and winter.Both rhizome and stolon tissue developed comparable levels of cold hardiness as measured by an artificial freeze test. A significant (P <; 0.05) reduction in percentage survival of tissue occurred at freeze‐test temperatures at or below −6.7 C on September 23 and Octobei 26; and −10.0, −8.9, and −12.8 C on November 30. January 10, and March 13, respectively. Total nonstructural carbohydrate (TNC) concentration of both rhizome and stolon tissue increased during September, remained relatively constant near 50% of dry weight until December, and was reduced to about 15% by March 15. Starch comprised the largest percentage of the carbohydrate fractions and closely followed TNC concentration. Total sugars increased slightly during fall, while reducing sugars remained nearly constant during the entire sampling period.