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Accurate identification of bermudagrass (Cynodon spp.) cultivars is necessary to ensure the purity of the cultivars produced by sod farmers, to protect the intellectual property of cultivar developers, and to assure cultivar purity for the benefit of turfgrass consumers. Vegetatively propagated turf bermudagrass cultivars have been extensively used in the turf industry not only in the USA but also in many other countries. Accordingly, the objectives of the study were to examine simple sequence repeat (SSR) markers for their ability to distinguish commonly grown clonal turf bermudagrass cultivars, which were derived through crosses and mutations, from each other and their respective parent cultivars and to develop a set of SSR markers for accurate identification of commercially used clonal cultivars. Thirty-two clonal turf bermudagrass genotypes comprising 29 commercially released cultivars and 3 Oklahoma State University experimental lines were assessed by 11 microsatellite markers. A total of 141 DNA fragments were generated for the 11 primer pairs in the 32 bermudagrass genotypes, with an average of 12.8 bands per primer pair. Forty-four fragments were cultivar specific. The SSR markers successfully identified 22 cultivars when mutant cultivars had the same banding patterns as the 2 parent cultivars, 'Tifgreen' and 'Tifway'. It was concluded from the study that the SSR markers are highly polymorphic and can be utilized as a reliable tool for accurate cultivar identification in nonmutated bermudagrass. doi: 10.2135/cropsci2010.02.0116

Cynodon transvaalensis Burtt-Davy (African bermudagrass) is used as a turfgrass and in interspecific hybridization to produce turfgrass cultivars. Information is lacking on the magnitude of intraspecific genetic variation for traits related to turfgrass performance. A Design II mating population comprised of 320 [F.sub.1] plants (4 parental sets, 16 crosses [set.sup.-1], 5 [F.sub.1] hybrids [cross.sup.-1]) was used to estimate genetic parameters for 21 traits. The [F.sub.1] plants were evaluated in replicated field (13 traits) and greenhouse (8 traits) experiments in Stillwater, OK during 2002-2003. Genetic variation was detected for 17 of the 21 traits as indicated by significant (P < 0.05) differences among families within sets. Both additive and dominance genetic effects were detected for most of the 17 traits, but dominance effects usually prevailed over additive effects. Broad sense heritability estimates varied from 0.42 to 0.96. Population improvement via recurrent selection techniques would be possible but difficult as indicated by low levels of additive genetic variation for genetic color, raceme number, seed number, and percent seed set. Dominance effects might be exploited to select clonally propagated [F.sub.1] hybrid cultivars with enhanced sensor-rated color, density, turf quality, spring greenup, fall dormancy, percent living cover, raceme number, raceme length, number of florets per inflorescence, plant height, stolon length, number of internodes, internode length, and leaf length.

Because golf course fairways often border water features, the potential loss of fertilizer nutrients in surface runoff from fairways can be significant. The objective of this study was to determine if bermudagrass buffers mowed at increasingly higher heights could reduce nutrient runoff from golf course fairways better than bermudagrass buffers mowed at a single height by providing multiple physical barriers to runoff. Grass buffers, 5.5 m long by 12.2 m wide, were positioned perpendicular to 5% slopes at the bottom of six 12.2 by 18.9 m bermudagrass (Cynodon dactylon L.) fairway plots. The buffers on three plots were mowed at a consistent 51 mm height. The remaining buffers included three 1.8 m sections that were mowed at increasingly higher heights of 25, 38, and 51 mm as surface elevation decreased. Runoff from both irrigation and natural rainfall were collected at 5-min intervals for 1 hr following the initiation of runoff and tested for nutrient concentrations. Irrigation was applied 4 hr after granular urea and triple superphosphate were applied. Graduated buffers of increasing height delayed the initiation of runoff by 4 min during fairway irrigation and by 2 min during natural rainfall events. The graduated buffer resulted in 17% less N, 11% less P, and 19% less runoff volume during 60 min of natural rainfall runoff. The graduated buffer resulted in 18% less N and 14% less P during 60 min of irrigation runoff, and reduced runoff volume by 16%., OF THE MORE THAN 16 000 golf courses in the USA, fairways comprise about 12 to 16 ha per course and account for the majority of intensively maintained turf (National [...]

Bermudagrasses (Cynodon spp.) are important for turf and forage in temperate and tropical climates, with cultivars historically propagated clonally. Over the past two decades the number of seed-propagated commercial cultivars has dramatically increased, but information is lacking on the extent of the genetic diversity among these new cultivars. Accordingly, this research was undertaken to assess the genetic relatedness of 17 seed-propagated turf-bermudagrass cultivars using DNA amplification fingerprinting (DAF). Four DAF and four Minihairpin-DAF (MHP-DAF) primers were used in this study. The DAF and MHP-DAF primers amplified 90 and 131 amplicons, respectively. A total of 13 out of the 17 cultivars were practically indistinguishable using the DAF primers with an average similarity [similarity coefficient (SC)] of 0.982 while the MHP-DAF primers distinguished all cultivars readily. Results from the DAF and MHP-DAF analysis indicated that 14 out of the 17 cultivars were related to Arizona common germplasm with average SC of 0.833 in the MHP-DAF analysis. Arizona common germplasm is naturalized to the Colorado River Valley production areas of Arizona and California. The three most distinct cultivars--'Princess 77', 'Yukon', and 'SWI-11'--had an average SC of 0.668. The most distinct cultivar was Yukon with an average SC of 0.604. Yukon showed 59 DNA signatures not observed in the other cultivars studied with DAF and MHP-DAF. These results indicated that a majority of seeded-type bermudagrasses developed over the past two decades depend on a narrow genetic base and that several recent cultivars are markedly genetically distinct, indicating a recent and significant broadening of the germplasm., BERMUDAGRASS (Cynodon dactylon L. Pers) is a perennial sod-forming turf and forage grass, native to India and eastern Africa (Beard, 1973, p. 132-593; Correll and Johnson, 1970). This grass is [...]

Bermudagrasses, Cynodon sp., are susceptible to winter injury in the transition zone for warm- and cool-season turfgrasses. Our objectives were to determine relative freeze tolerance of recently released and standard cultivars using laboratory-based methodology, and to determine the effect of extended exposure duration on survival. Plants were clonally propagated, then established and acclimated in growth chambers before exposure to a range of temperatures in a freeze chamber. 'Tifway' and 'TifSport' (-7.9°C) were significantly hardier than 'Princess' (-6.9°C), but less freeze tolerant than 'U-3' (-8.9°C), 'Patriot' (-9.7°C), and 'Midlawn' (-10.3°C). Riviera (-8.3°C) was significantly hardier than Princess, but less freeze tolerant than Patriot and Midlawn. In a second set of experiments, acclimated plants were held at constant, subfreezing temperatures for various periods of time in a refrigerated bath. Survival of U-3 and Riviera decreased to 25% or less when exposed to -7.0°C for 2 or 5 d, compared with 100 and 83% survival, respectively, when plants were removed from the bath immediately after equilibrating at -7.0°C. Princess exhibited 89% survival when removed immediately after equilibrating at -5.4°C, but survival after 2, 24, and 72 h was 67, 30, and 11%, respectively. Although minimum exposure temperature is a primary determinant of survival, freeze damage to turf bermudagrasses increased as exposure duration increased., BERMUDAGRASSES GROWN in the transition zone for warm- and cool-season grasses are subject to freeze damage (Fry, 1990; Hiscock, 1996). Information on relative freeze tolerance is vital to turfgrass managers [...]

Accurate identification of bermudagrass (Cynodon spp.) cultivars is necessary to ensure the purity of the cultivars produced by sod farmers, to protect the intellectual property of cultivar developers, and to assure cultivar purity for the benefit of turfgrass consumers. Vegetatively propagated turf bermudagrass cultivars have been extensively used in the turf industry not only in the USA but also in many other countries. Accordingly, the objectives of the study were to examine simple sequence repeat (SSR) markers for their ability to distinguish commonly grown clonal turf bermudagrass cultivars, which were derived through crosses and mutations, from each other and their respective parent cultivars and to develop a set of SSR markers for accurate identification of commercially used clonal cultivars. Thirty-two clonal turf bermudagrass genotypes comprising 29 commercially released cultivars and 3 Oklahoma State University experimental lines were assessed by 11 microsatellite markers. A total of 141 DNA fragments were generated for the 11 primer pairs in the 32 bermudagrass genotypes, with an average of 12.8 bands per primer pair. Forty-four fragments were cultivar specific. The SSR markers successfully identified 22 cultivars when mutant cultivars had the same banding patterns as the 2 parent cultivars, 'Tifgreen' and 'Tifway'. It was concluded from the study that the SSR markers are highly polymorphic and can be utilized as a reliable tool for accurate cultivar identification in nonmutated bermudagrass. [ABSTRACT FROM AUTHOR]

For municipalities across Oklahoma and the southern United States, maximum domestic water usage occurs during July and August, and up to 50% of this water is used outdoors. There is a need to conserve water resources through reduced outdoor irrigation. The objective of the Extension project described here was to teach Oklahoma Master Gardeners a simple technique to effectively measure lawn irrigation output through simple irrigation audit workshops. Seventy-six Master Gardeners participated in three simple irrigation audit workshops across Oklahoma. The results suggest that simple irrigation workshops can significantly increase Master Gardener knowledge of home lawn irrigation system output. [ABSTRACT FROM AUTHOR]