Cool-season Turf Research Articles

Seasonal Quality of Some Cool-Season Turfgrass Species in Cold Semi-Arid Climate

The study was carried out to determine winter hardiness, establishment speed, and seasonal variation in quality characteristics of some turf cultivars belonging to the common cool-season turf species in cold semi-arid climates. Nineteen different cultivars of perennial ryegrass, tall fescue, red fescue, Chewing’s fescue, slender creeping red fescue, and Kentucky bluegrass were examined for six seasons in 2014-2016 years. The experiment was arranged in a randomized complete block design with three replications. The score-based measurements of turf texture, color, and general quality were taken in the middle of every season (2 summers, 2 springs, and 2 falls) for 2 years and the data were analyzed using non-parametric tests. Results showed that Stravinsky (perennial ryegrass) and Cardinal (red fescue) greatly lost their dark green color in autumn, while SR8600 (tall fescue) kept its satisfying green color. General quality decreased as the seasons proceeded, but Rosita (slender creeping red fescue) remained in high quality considering other red fescue species. Low adaptation ability was observed in Miracle and Evora cultivars of Kentucky bluegrass species due to their poor winter hardiness scores. These cultivars are also the slowest establishing among other cultivars. Results stated that Stravinsky, Esquire, Kokomo, Grandslam2 (perennial ryegrass), Maximal (red fescue), and Rosita (slender creeping red fescue) maintained high quality throughout summer and spring but decreased in autumn. However, Forte (tall fescue) and Evora (Kentucky bluegrass) presented better quality in autumn but the quality of Evora decreased in the next year. These cultivars should be used in a mixture to maintain high-quality turf through spring, summer, and autumn but Evora could require overseeding in some years. More and especially newly released cultivars should be tested to increase the turf quality of the mixtures.

Cool- and Warm-Season Turfgrass Irrigation with Subsurface Drip and Sprinkler Methods Using Different Water Management Strategies and Tools

This study compared the performances of subsurface drip irrigation (SDI) to sprinkler irrigation (SI) of cool-season turf mix (CS) and warm-season (WS) turfgrass species while investigating their response to different irrigation scheduling strategies. Moreover, the suitability of crop water stress index (CWSI) for monitoring water stress and scheduling irrigation was tested. Irrigation was applied up to the field capacity when 30%, 50% and 70% of total available water was consumed. All parameters, including color, quality, fresh yield, dry matter yield, irrigation water productivity, water productivity, vegetation height and mowing, differed significantly for different irrigation methods and water supply strategies for both species. The best visual turf was maintained under non-limiting soil moisture conditions (30%) in all main and sub-treatments. At this irrigation threshold, maximum and minimum amounts of irrigation water were applied in SI CS treatment (523.5 mm) and SDI WS treatment (298.6 mm), respectively. Warm-season turf required up to 40% less water than cool-season turf mix. In the water-scarce regions, 50% treatment for cool-season and 70% treatment for warm-season can be suggested for acceptable visual quality, lower water consumption and less frequent clipping. The mean CWSI before irrigation, representing irrigation threshold, ranged between 0.22–0.70.

Genome-wide identification of heat shock transcription factor families in perennial ryegrass highlights the role of LpHSFC2b in heat stress response.

Perennial ryegrass (Lolium perenne) is a cool-season turf and forage grass. Heat shock transcription factors (HSFs) play an important role in regulating plant abiotic stress. However, HSFs in perennial ryegrass have rarely been characterized. Here, 25 LpHSFs were identified from the perennial ryegrass genome. Phylogenetic analysis showed that the LpHSFs could be classified into 12 subclasses. Gene structure analysis showed that 22 LpHSFs have only one intron. Cis-acting elements analysis revealed that the promoter of 15 LpHSFs contained hormone-responsive and abiotic stress-responsive elements. Expression profile analysis indicated that 24 LpHSFs were differentially expressed under submerge, drought, heat, and cold stresses. In addition, a subclass C2 gene, LpHSFC2b, was significantly induced by abiotic stresses. The LpHSFC2b protein is localized to the nucleus, and heterologous expression of LpHSFC2b in Arabidopsis improves plant thermotolerance. This study provides insights useful for the breeding of stress tolerance in perennial ryegrass.

Peyzaj uygulamalarında kullanılan bazı çim çeşitlerinde farklı tuz yoğunluklarının çimlenme üzerine etkileri

This study was conducted in laboratory conditions to determine the response of some cool season turf grass species (Lolium perenne Caddieshack, Lolium multiflorum Jivet, Poa pratensis Evora, Festuca rubra Rassinante, Festuca arundinacea Starlet, Festuca ovina Ridu) to different salt doses during the germination period. In the study, 8 different NaCl doses, 0, 30, 60, 90, 120, 150, 180, 210 mM, were applied, germination rate (%), germination time (%), plumula length (cm), radicula length (cm) and vigor index values were examined. Because of the research, it was observed that the germination rate, plumula and radicula lengths increased at 30 mM concentrations and in general, significant damage occurred after the dose of 90 mM. Lolium perenne Caddieshack and Lolium multiflorum Jivet species showed the highest mean values and were less affected by increasing salt doses in all properties examined.

The complete chloroplast genome of Agrostis capillaris L

Agrostis capillaris is a cool-season turf grass species that is found worldwide in temperate countries, and a good Pb phytostabilizer. In this study, the entire chloroplast genome sequence of A. capillaris was determined by Illumina sequencing. The complete chloroplast genome was circular and composed of 136,396 bp nucleotides with a GC content of about 38.5%. There were a large single-copy region (LSC, 81,659bp), a small single-copy region (SSC, 12,593bp), and a pair of reverse repeat regions (IRs, 42,144bp) in the chloroplast genome. In total, the A. capillaris chloroplast genome contained 144 genes, including 96 protein-coding genes, 40 tRNA genes, and 8 rRNA genes. Phylogenetic analysis revealed that A. capillaris was closely related to A. gigantean. The sequence data of A. capillaris chloroplast genome could provide useful genetic information for the studies on phylogenetic and evolutionary of Agrostidinae.

Harmony, quality and continuity characteristics of cool season turf grasses in Samsun conditions

Bu çalışma, Samsun ekolojik şartlarında bazı serin iklim yeşil alan bitkilerinin uyumunu ve kalite özelliklerini belirlemek amacıyla, Kasım 2010 ile Aralık 2012 tarihleri arasında eksik bloklar deneme desenine göre dört tekrarlamalı olarak yürütülmüştür. Denemede bitki materyali olarak Çok yıllık çim (L. perenne L.), Kamışsı yumak (F. arundinacea Schreb.), Rizomsuz kırmızı yumak (F. rubra L. subsp. commutata), Rizomlu kırmızı yumak (F. rubra L. subsp. rubra), Narin kırmızı yumak (F.rubra trchophyla), Koyun yumağı (F. ovina L.), Çayır salkım otu (P. pratensis L.), Adi salkım otu (P. trivialis L.), Stolonlu tavusotu (A. stolonifera L.), Narin tavusotu (A. tenuis Sibth.) türlerine ait 38 adet serin iklim yeşil alan çim çeşidi kullanılmıştır. Araştırmada ilk yıl çıkış hızı ve kaplama hızı, ikinci yıl kaplama derecesi, yenilenme gücü, kışa dayanıklılık ve yeşil kütle verimi gözlem ve ölçümleri alınmıştır. Çıkış hızı, kaplama hızı ve derecesi yönleriyle çok yıllık çim ve kamışsı yumak; yenilenme gücü açısından narin kırmızı yumak; kış koşullarına dayanıklılık bakımından narin kırmızı yumak, tavus otu ve kamışsı yumak; yeşil kütle veriminin düşüklüğü yönünden çayır salkım otu ve adi salkım otu çeşitleri öne çıkmıştır. Yeşil alanlarda ekilen tohumların hızla çimlenip çıkış yaparak ortamı kapatmaları, olumsuz koşullardan olabildiğince az etkilenmeleri, yenilenme gücünün yüksek olması ve bakım masraflarını azaltabilmek adına kütle verimlerinin düşük olması istenir. Bu özelliklerin tümünü tek bir tür veya çeşitte bulmak mümkün görünmemektedir. Bu nedenle, istenen özelliklere en yakın sonuçlara ulaşabilmek için, bölge koşullarına uygun karışımların hazırlanmasının çok önemli olduğu sonucuna varılmıştır.

EFFECT OF CUTTING HEIGHTS ON THE TURF AND PLAYING QUALITY TRAITS OF SOME TURF ALTERNATIVES IN A MEDITERRANEAN ENVIRONMENT

Among cool-season turf grasses tall fescue (Festuca arundinacea Schreb.) exhibits the best adaptation to the Mediterranean Ecologies. Many turf type cultivars of this drought and heat resistant turf grass have been recently released and therefore management practices consequently should be adapted. The purpose of the study was to detect the agronomic and sports field characteristics of some turf type tall fescue and traditional cool season sports turf mixture mowed at different heights in a Mediterranean environment and to determine the most favorable turf grass alternative and mowing regime. The trial was carried out in the experimental fields of Bayindir Vocational School, Izmir (Turkey), using three different turf alternatives (Tall Fescue 100%, Tall Fescue 60% + Perennial Rye Grass 40% mixture and Traditional Cool Season Sports Turf Mixture: Perennial Rye Grass 50%, Creeping Red Fescue 20%, Chewing's Red Fescue 10%, Sheep Fescue 10%, Kentucky Blue Grass 10%) under 12, 22 and 32 mm mowing height regime. Visual turf quality, texture and weed invasion traits were determined and shock absorption and vertical deformation were also measured as playing quality parameters for a sports turf. Turf alternatives of tall fescue except traditional cool season sports turf mixture showed an adaptation to low mowing height which increased shoot density and promoted a finer leaf texture. Shock absorption and vertical deformation traits were significantly affected by mowing heights, highest value being recorded for the lowest mowing heights. Nevertheless, a good sports field quality was determined for the tall fescue and tall fescue + perennial ryegrass plots. The results of the present work showed that tall fescue, if maintained at low mowing height regime, could provide a dense and fine textured turf suitable for sport fields with a high visual turf quality.

Genetic variability evaluation and cultivar identification of tetraploid annual ryegrass using SSR markers.

Annual ryegrass (Lolium multiflorum) is a widely used cool-season turf and forage grass with high productivity and ornamental characteristics. However, the abundant intra-cultivar genetic variability usually hampers the application of conventional techniques for cultivar identification. The objectives of this study were to: (1) describe an efficient strategy for identification of six tetraploid annual ryegrass cultivars and (2) investigate the genetic diversity based on SSR markers. A total of 242 reliable bands were obtained from 29 SSR primer pairs with an average of 8.3 bands for each primer pair and the average value of polymorphic information content (PIC) was 0.304. The result of analysis of molecular variance (AMOVA) revealed that 81.99% of the genetic variation occurred in within-cultivars and 18.01% among-cultivars. The principal coordinate analysis (PCoA) showed that the first two principal axes explain 8.57% (PC1) and 6.05% (PC2) of total variation, respectively. By using multi-bulk strategy based on different filtering thresholds, the results suggested that bands frequency of 40% could be used as a reliable standard for cultivar identification in annual ryegrass. Under this threshold, 12 SSR primer pairs (00-04A, 02-06G, 02-08C, 03-05A, 04-05B, 10-09E, 12-01A, 13-02H, 13-12D, 14-06F, 15-01C and 17-10D) were detected for direct identification of six tetraploid annual ryegrass cultivars, which could be incorporated into conservation schemes to protect the intellectual property of breeders, ensure purity for consumers, as well as guarantee effective use of cultivars in future.

False-green kyllinga (Kyllinga gracillima) control in cool-season turfgrass

AbstractWe conducted research to evaluate various herbicides for POST false-green kyllinga control in cool-season turfgrass (primarily creeping bentgrass). In a preliminary evaluation, single and sequential applications of halosulfuron-methyl (70 g ai ha−1), mesotrione (175 g ai ha−1), and sulfentrazone (140 g ai ha−1), as well as a single application of imazosulfuron (740 g ai ha−1), were evaluated in New Jersey. Imazosulfuron and sequential applications of halosulfuron-methyl controlled false-green kyllinga >93% at 9 and 18 wk after initial treatment (WAIT). Sulfentrazone and mesotrione controlled false-green kyllinga <50%. Additional experiments were conducted to evaluate single and sequential applications of halosulfuron-methyl (70 g ha−1), imazosulfuron (420 and 740 g ha−1), and sulfentrazone (140 g ha−1) in New Jersey and Indiana at two locations in each state. At 12 WAIT, imazosulfuron generally controlled false-green kyllinga more effectively than other treatments at all locations. Sequential applications of imazosulfuron controlled false-green kyllinga 100% at 12 WAIT. Halosulfuron-methyl was less effective in Indiana than in New Jersey. Sulfentrazone controlled false-green kyllinga <40% at 12 WAIT. This research demonstrates that imazosulfuron is more effective than halosulfuron-methyl and sulfentrazone for POST false-green kyllinga control in cool-season turf.

EFFECT OF DROUGHT ON THE PERFORMANCE OF THREETURF GRASS SPECIES

Drought is the main environmental factor hampering world agriculture production. In the face of warmingclimate and reduced fresh water resources it become obvious that search for any factors decreasing water useis strongly recommended. Turf grasses able to withstand drought period longer could be recommended for turfareas as parks, lawns, home gardens etc. and relatively lower amounts of water should ensure satisfactory turfquality. Therefore, twelve turf varieties from three major cool-season turf grass species: perennial ryegrass(Lolium perenne L.), Kentucky bluegrass (Poa pratensis L.) and red fescue (Festuca rubra L.) were tested inglasshouse pot experiment and in the laboratory for determination of their relative ability to withstand greenlonger in the face of water deficit.The different response of the examined forms to drought was noted. Conditions that favor fast water depletionwere the most suitable for the expression of water deficit-related traits. Therefore, sandy mixture of 16%volumetric moisture content at field water capacity was mostly suitable for observation of the variation oftested forms. Turf condition of Kentucky bluegrass, as contrary to red fescue, was strongly connected with thesoil moisture. Different manifestation of drought resistance was observed in tested species. Kentucky bluegrass,as rather no resistant to drought, exposed low level of drought avoidance. Red fescue was able to survivedrought mainly due to leaf blades resistant to desiccation. In perennial ryegrass some other mechanismsevolved to survive drought. Early leaf wilting and senescence contributes to nutrient remobilization duringdrought and avoids large water loses during the transpiration. Therefore, perennial ryegrass turf was able toregenerate better after drought, as compared to the other tested grass species.Search for new turf forms should focus on searching for ability to maintain acceptable conditions longer ina presence of increasing water deficit. It will then reduce the duration of period of poor turf conditions andfurther, turf water demands.

Antioxidant Metabolism, Photosystem II, and Fatty Acid Composition of Two Tall Fescue Genotypes With Different Heat Tolerance Under High Temperature Stress.

Tall fescue (Festuca arundinacea Schreb.) is a typical and widely used cool-season turf grass. High temperature is a key factor that limits its utility. The objectives of this study were to investigate the behaviors of fatty acid composition and its gene expression patterns in heat-resistant genotype “TF71” and heat-sensitive genotype “TF133” exposed to heat stress (40/35°C, 14/10 h), and to broaden our comprehension about the relationship between heat tolerance and fatty acid function. The result showed that heat stress increased the malondialdehyde (MDA) content and relative electrolyte leakage (EL), but decreased the level of chlorophyll and the activity of superoxide dismutase (SOD) and peroxidase (POD) when compared to the controls, to a greater extent in “TF133.” This result proved that “TF71” had superior high-temperature resistance. Furthermore, comparing the changes in the composition of fatty acid and the expression of the genes involved in its synthesis between the two different genotypes under heat stress, we found that heat stress increased the degree of unsaturation, UFA/SFA, and double bond index (DBI) in “TF71.” Moreover, quantitative RT-PCR revealed that heat stress altered the expression of the genes involved in fatty acid synthesis, including ACAC, FabD, FabF, FabH, FabI, and FatA. According to these findings, we can speculate that increasing the unsaturation degree of fatty acid or controlling the equilibrium ratio of UFA/SFA might be closely associated with the improving of the heat resistance in tall fescue.

Physiological and biochemical analyses reveal drought tolerance in cool-season tall fescue (

Tall fescue (Festuca arundinacea Schreb.) is a widely used, cool-season turf grass and is relatively sensitive to water stress. Melatonin has been reported to improve abiotic stress tolerance in many plants. In this study, we demonstrated that, although shoot height and fresh weight of tall fescue seedlings were significantly reduced by drought stress, they were increased by melatonin pre-treatment compared with control plants. Chemical analyses showed that tall fescue seedlings pre-treated with melatonin exhibited decreased levels of reactive oxygen species, electrolyte leakage and malondialdehyde, but higher levels of antioxidant enzyme activities (catalase, and peroxidase) and total chlorophyll content, compared with untreated seedlings. Leaf water loss was also partially mitigated and leaf water content increased by melatonin application, resulting in improved plant growth under drought stress. Moreover, root growth of tall fescue seedlings was promoted by melatonin under osmotic stress. The results show that drought tolerance was improved in cool-season tall fescue by application of exogenous melatonin. Therefore, melatonin may potentially be used as a protectant for plants against the deleterious effects of drought or water-deficit stress.

Steaming and Flaming for Converting Cool-season Turfgrasses to Hybrid Bermudagrass in Untilled Soil

Turfgrass species can be classified into two main groups: cool-season and warm-season species. Warm-season species are more suited to a Mediterranean climate. Transplanting is a possible method to convert a cool-season to a warm-season turfgrass in untilled soil. It generally requires the chemical desiccation of the cool-season turfgrass. However, alternative physical methods, like flaming and steaming, are also available. This paper compares flaming, steaming, and herbicide application to desiccate cool-season turfgrass, for conversion to hybrid bermudagrass (Cynodon dactylon x C. transvaalensis) in untilled soil, using transplanting. Two prototype machines were used, a self-propelled steaming machine and a tractor-mounted liquefied petroleum gas flaming machine. Treatments compared in this work were two flaming treatments and two steaming treatments performed at four different doses together with two chemical treatments with glufosinate-ammonium herbicide applications. The cool-season turfgrass species were tall fescue (Festuca arundinacea) and perennial ryegrass (Lolium perenne). The desiccation effect of the various treatments on cool-season turf was assessed by photographic survey 15 days after treatment. The percentage cover of hybrid bermudagrass was visually assessed at 43 weeks after planting. Steaming and flaming effects on both parameters were described by logistic curves. The highest doses of steaming and flaming almost completely desiccated cool-season turf, and similar hybrid bermudagrass cover was established by both the methods as the chemical application (50% to 60%). Thus both flaming and steaming may be considered as valid alternatives to herbicides aimed at turf conversion.

Long-Term Roughstalk Bluegrass Control in Creeping Bentgrass Fairways

Methiozolin is an isoxazoline herbicide that selectively controls annual bluegrass in cool-season turf and may control roughstalk bluegrass, another weedyPoaspecies that is problematic in many turfgrass systems. However, the majority of research to date is limited to evaluating methiozolin efficacy for annual bluegrass control in creeping bentgrass putting greens. Research was conducted comparing various application regimes of methiozolin and other herbicides for long-term roughstalk bluegrass control in creeping bentgrass golf fairways. Methiozolin-only treatments did not injure creeping bentgrass or reduce normalized difference vegetative index (NDVI) at 2 golf course locations based on 20 evaluation dates over a 2.5-yr period. The 2.5-yr average turf quality generally declined as roughstalk bluegrass control increased due to transient turf cover loss. At 1 yr after last treatment, methiozolin at 1500 g ai ha-1applied four times in fall reduced roughstalk bluegrass cover 85%. This was equivalent to methiozolin at 1000 g ha-1applied four times in fall, but greater than low rates of methiozolin applied four times in spring or twice in fall and spring. Amicarbazone, primisulfuron, and bispyribac-sodium alone either did not effectively reduce roughstalk bluegrass cover, or did so at the expense of increased creeping bentgrass injury. Results of this study suggest that methiozolin alone or tank-mixed with amicarbazone or primisulfuron is an effective long-term approach for selectively controlling roughstalk bluegrass in creeping bentgrass.

South Coast REC: Linking urban landscapes, water conservation and water quality

News from the RECs South Coast REC: Linking urban landscapes, water conservation and water quality D arren Haver, director of South Coast Research and Extension Center (REC), arrives at work without leaving the Irvine suburbs. Passing block after block of housing, old developments and new, he sees irrigation water sheeting off concrete driveways into drains. Reaching the 200-acre REC, which soon will have housing developments right up to the fences, he hears the water running off the driveways of the realistically landscaped housing sites he’s had built at the center. Here, Haver, who also serves as county director and water resources/quality advisor for UC ANR Cooperative Extension (UCCE) in Orange County, is studying two major aspects of residential water use: how much is used in different landscapes, and how much pollution occurs in any runoff from those landscapes. From 50% to 70% of residential water use is applied to land- scaping. Typically the landscaping is over-irrigated, producing runoff that enters storm drains and creeks and eventually the ocean. The runoff may contain pesticides, most commonly pyre- throids found in lawn insecticides and ant sprays, which are en- tering urban watersheds at levels toxic to aquatic invertebrates. The landscaped housing sites at South Coast REC are test- ing best management practices (BMPs) for residential water conservation and environmental protection. They serve as dem- onstration gardens for local homeowners and are inspiring new partnerships beyond UC — with pesticide manufacturers, for example, and even big-box stores. The residential-use water study began here in this uniquely urban REC in 2005. With environmental chemist Jay Gan, at UC Riverside’s (UCR) Department of Environmental Sciences, and entomologists Les Greenberg and Michael Rust, in the UCR Department of Entomology, Haver was investigating how in- secticides were reaching local creeks. Haver became interested in the very high use of ant sprays and lawn insecticides around Darren L. Haver Researchers at South Coast REC use these three landscaped home sites to study water use and pesticide runoff. From left: Site A, Site B and Site C. 6 CALIFORNIA AGRICULTURE • VOLUME 70 , NUMBER 1 homes. “Nobody at that time had a clue about what happens when you apply those sprays to concrete or bricks,” recalls Haver — or how much of the chemicals runs off-site. Three home sites were built at South Coast REC in 2006 to develop, test and implement BMPs for residential landscaping. Each is 40 feet wide by 100 feet long, with a 24-by-24-foot struc- ture, to simulate a home, and a landscaped yard with a standard 2% slope to the curb. Site A, the typical landscape site, includes cool-season turf and big-box store plants such as white birch; it has a poorly installed sprinkler irrigation system, and the controller is set to the default position, providing water regularly regardless of weather conditions. A solid concrete driveway funnels roof wa- ter and landscape runoff away from the house. Site B has a low-impact design, sometimes called Mediterranean, used in new housing developments. It has less lawn area, warm-season grass, plants that have some drought tolerance, a better irrigation design with soil moisture sensors, and some permeable flagstone walkway paving and slot drains in the driveway to divert water to planting beds. Site C is a model of sustainability and water conservation. It has native landscaping, with native Southern California plants, a native sedge lawn, permeable paving and a smart drip irriga- tion controller that uses weather data from the previous day. Multiple studies by UC researchers — at the South Coast REC test home sites and elsewhere — have helped to establish the significance of home landscapes as a source of environmental contaminants. Research undertaken with scientists at the UCR Department of Environmental Sciences (Jiang et al. 2010) showed that pyre- throid insecticides and fipronil (common in ant sprays) are per- sistent in home landscapes. They were still present in wash-off water 112 days after application to concrete, and for more than 42 days after 14 washing-drying cycles. At the American Chemical Society National Meeting in 2010, Haver presented, with fellow researchers Tamara Majcherek, from the UC Davis Department of Plant Sciences, and Jay Gan and Sveta Bondarenko, from the UCR Department of Environmental Sciences, the results from an experi- ment that involved washing down the

Soil Fertility Amendments and White Grub Populations of Turf

Liming materials, calcium carbonate versus calcium magnesium silicate, were compared for effects on native white grub (Coleoptera: Scarabaeidae) populations in a New Jersey lawn. A silt loam soil near Princeton, N.J., of mixed cool-season turf with an initial pH of 5.0 received applications of either liming material in January 2007 for a target pH of 6.5. Control plots received no lime application. Grub numbers were reduced by more than 50% in plots amended with either calcium magnesium silicate or calcium carbonate when compared with the controls. Both calcium magnesium silicate and calcium carbonate were similarly effective in achieving this benefit.

A PCR-based linkage map of Agrostis stolonifera and identification of QTL markers for dollar spot resistance

Creeping bentgrass (Agrostis stolonifera L.) is the most widely utilized cool-season turf species for intensively managed sports playing surfaces, including bowling greens and golf course putting greens, tees, and fairways. One of the biggest disease problems affecting creeping bentgrass is dollar spot disease caused by Sclerotinia homoeocarpa F.T. Bennett. Relative to traditional food crops, little attention has been paid to applying molecular technology to traditional creeping bentgrass breeding programs. The objective of this study was to develop a PCR-based linkage map of creeping bentgrass and identify quantitative trait loci (QTLs) associated with dollar spot resistance. Mapping populations segregating for dollar spot resistance were created, phenotyped for disease resistance, and genotyped for simple sequence repeat, conserved intron scanning primer, intron length polymorphism, and amplified fragment length polymorphism markers. As expected, 14 linkage groups (LGs) were detected for each parental map, covering a total of 1,424 and 1,374 cM for the 7418-3 and the L93-10 parental maps, respectively. A total of eight QTL regions (23 markers) for dollar spot resistance were observed for three isolates (Crenshaw, PRG, and UMass1) in our creeping bentgrass mapping populations. LGs 1, 4, and 5 contained at least two overlapping QTL regions to different isolates, indicating that these regions may play a significant role in dollar spot resistance. Identification of QTLs associated with disease resistance will help to facilitate marker-assisted selection in traditional creeping bentgrass breeding programs.

Adaptability of Newly Improved Creeping Bentgrass (Agrostis stolonifera L.) Genotypes in a Mediterranean Environment

Creeping bentgrass (Agrostis stolonifera L.), with a mild shade tolerance, is a stoloniferous cool season turf grass adaptable to temperate climatic conditions. Recently new genotypes were improved by breeders in the USA, having respectively higher heat and drought tolerance. In an attempt to evaluate the adaptability of this type of bentgrass genotypes, an experiment were established on the experimental farm located at Bornova, Ege Univ. Agric. Faculty, Izmir, Turkey during the years of 2007 and 2009. Six genotypes of bentgrass and traditional cultivar “Kromi” as control were tested for two years and turf grass color, cover, weed infestation and turf quality were assessed by a visual scoring (1-9 points). Results indicated significant variations among the genotypes in terms of the evaluated characteristics and the average adaptability of some genotypes of which some traits such as cover and turf quality were in an acceptable range. It was also suggested that distinguished genotypes such as genotype M65-6-OVN-28, M71-6-26-294 and M39-6-20 should be tested furthermore and for other agronomical characteristics

Development of SCAR markers and UP-PCR cross-hybridization method for specific detection of four major subgroups of Rhizoctonia from infected turfgrasses

A rapid identification assay for Waitea circinata (anamorph: Rhizoctonia spp.) varieties zeae and circinata causing patch diseases on turfgrasses was developed based on the universally primed PCR (UP-PCR) products cross-blot hybridization. Tester isolates belonging to the two varieties of W. circinata were amplified with a single UP primer L21, which generated multiple DNA fragments for each variety. Probes were prepared with UP-PCR products of each tester isolate by labeling with digoxigenin. Fieldcollected W. circinata isolates and representative isolates of different R. solani anastomosis groups (AG) and AG subgroups were amplified with L21, immobilized on nylon membrane and cross hybridized with the two probes. Isolates within a W. circinata variety cross-hybridized strongly, while non-homologous isolates did not cross-hybridize or did so weakly. Closely related W. circinata varieties zeae and circinata were clearly distinguished with this assay. Sequence-characterized amplified region (SCAR) markers also were developed from UP-PCR products to identify isolates of Thanatephorus cucumeris (anamorph: R. solani) AG 1-IB and AG 2-2IIIB. These two AGs are commonly isolated from diseased, cool-season turfgrasses. The specific SCAR markers that were developed could differentiate isolates of AG 1-IB or AG 2-2IIIB groups. These SCAR markers did not amplify a product from genomic DNA of nontarget isolates of Rhizoctonia. The specificities and sensitivities of the SCAR primers were tested on total DNA extracted from several field-grown, cool-season turf species having severe brown-patch symptoms. First, the leaf samples from diseased turf species were tested for the anastomosis groups of the causal pathogen, and thereafter the total DNA was amplified with the specific primers. The specific primers were sensitive and unique enough to produce a band from total DNA of diseased turfgrasses infected with either AG 1-IB or AG 2-2IIIB.

Off-Target Injury to Southern Landscape Species Following Aminocyclopyrachlor Applications

Aminocyclopyrachlor is an herbicide for broadleaf weed control that has recently come under scrutiny following reports of injury to landscape ornamentals across the upper Midwestern United States. This herbicide has been shown to provide excellent weed control in warm-season turfgrasses at much lower use rates than that used for cool-season turf, but data are lacking concerning its safety to landscape ornamentals in southern U.S. regions. Parallel studies were conducted in Dallas and Huntsville, TX, locations to evaluate off-target injury effects on sixteen ornamentals and trees commonly used in southern landscapes. In March 2012, just prior to the spring growth flush, aminocyclopyrachlor was applied to potted plants at 0, 0.5, 1, 2, or 4× rates as either as granular [0, 14, 28, 56, or 112 g ai·ha−1 (0.013, 0.03, 0.05, and 0.10 lbs ai·A−1)] or liquid [0, 11.2, 22.4, 44.8, or 89.6 g ai·ha−1 (0.01, 0.02, 0.04, 0.08 lbs ai·A−1)] formulations. For the next 8 weeks, plants were evaluated for injury to new growth. Injury was observed in 9 of the 16 species used, but was generally mild to moderate in nature. Species exhibiting the greatest sensitivity to aminocyclopyrachlor included loblolly pine (Pinus taeda), viburnum (Viburnum odoratissimum), nandina (Nandina domestica ‘Compacta’), and camellia (Camellia japonica). Extent of injury was not different between granular or liquid formulations, but was less severe at the Dallas location. Results of the study indicate sensitivity within some southern landscape ornamentals to aminocyclopyrachlor.