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Poa pratensis, commonly known as Kentucky bluegrass, is a popular cool-season grass species used as turf in lawns and recreation areas globally. Despite its substantial economic value, a reference genome had not previously been assembled due to the genome's relatively large size and biological complexity that includes apomixis, polyploidy, and interspecific hybridization. We report here a fortuitous de novo assembly and annotation of a P. pratensis genome. Instead of sequencing the genome of a C4 grass, we accidentally sampled and sequenced tissue from a weedy P. pratensis whose stolon was intertwined with that of the C4 grass. The draft assembly consists of 6.09 Gbp with an N50 scaffold length of 65.1 Mbp, and a total of 118 scaffolds, generated using PacBio long reads and Bionano optical map technology. We annotated 256K gene models and found 58% of the genome to be composed of transposable elements. To demonstrate the applicability of the reference genome, we evaluated population structure and estimated genetic diversity in P. pratensis collected from three North American prairies, two in Manitoba, Canada and one in Colorado, USA. Our results support previous studies that found high genetic diversity and population structure within the species. The reference genome and annotation will be an important resource for turfgrass breeding and study of bluegrasses.

Consumers often have multiple choices when purchasing retail lawn products in stores. In this study, we evaluated the acute drought performance of locally available retail lawn seed products (mixtures or blends) at two mowing heights of 2.5 and 3 inches. We hypothesized that the species present in the products and the height-of-cut differentially influence the drought resistance and recovery of the mixtures and blends. In Fall 2016 and 2017, 28 different products consisting of 25 mixtures and 3 blends of turfgrass seeds were established under a fully automated rainout shelter at the St. Paul campus of the University of Minnesota. The drought treatments lasted for 67 days in 2017, and 52 days in 2018; both the 2017 and 2018 treatments were followed by a recovery period. Data were obtained during acute drought treatments and recovery periods for visual turfgrass quality and green turfgrass cover using digital images of the plots. During the first year, several products displayed higher green stability (or the ability to remain green) at the 3-inch height-of-cut compared with the 2.5-inch height-of-cut. Products with tall fescue (Schedonorus arundinaceus) and fine fescue (Festuca sp.) as dominant species generally performed better during the drought treatments, whereas an increasing presence of perennial ryegrass (Lolium perenne) and kentucky bluegrass (Poa pratensis) decreased the visual drought performance of the products. During the recovery period, an effect of the interaction between mowing height and the date of data collection on the percentage of green cover was observed: the lower mowing height improved the early recovery of green cover after acute drought. These findings suggest that consumers in the upper midwestern United States and areas with a climate similar climate to that of St. Paul, MN, who are challenged with multiple choices of lawn seed prod

Consumers often have multiple choices when purchasing retail lawn products in stores. In this study, we evaluated the acute drought performance of locally available retail lawn seed products (mixtures or blends) at two mowing heights of 2.5 and 3 inches. We hypothesized that the species present in the products and the height-of-cut differentially influence the drought resistance and recovery of the mixtures and blends. In Fall 2016 and 2017, 28 different products consisting of 25 mixtures and 3 blends of turfgrass seeds were established under a fully automated rainout shelter at the St. Paul campus of the University of Minnesota. The drought treatments lasted for 67 days in 2017, and 52 days in 2018; both the 2017 and 2018 treatments were followed by a recovery period. Data were obtained during acute drought treatments and recovery periods for visual turfgrass quality and green turfgrass cover using digital images of the plots. During the first year, several products displayed higher green stability (or the ability to remain green) at the 3-inch height-of-cut compared with the 2.5-inch height-of-cut. Products with tall fescue (Schedonorus arundinaceus) and fine fescue (Festuca sp.) as dominant species generally performed better during the drought treatments, whereas an increasing presence of perennial ryegrass (Lolium perenne) and kentucky bluegrass (Poa pratensis) decreased the visual drought performance of the products. During the recovery period, an effect of the interaction between mowing height and the date of data collection on the percentage of green cover was observed: the lower mowing height improved the early recovery of green cover after acute drought. These findings suggest that consumers in the upper midwestern United States and areas with a climate similar climate to that of St. Paul, MN, who are challenged with multiple choices of lawn seed prod

The story goes that all thoroughbreds, unless bred fraudulently, descend from three foundation sires taken to Great Britain from the Levant, the Maghreb, and Arabia in the late-seventeenth and early-eighteenth centuries. That’s just a story, though, and a breed is more a term of art than a scientific fact. Historian William Cronon implored environmental historians to tell “stories about stories about nature.” The stories people told about thoroughbreds over the breed’s three-century history illuminate unspoken assumptions of their society, assumptions about how inheritance works, about how to organize labor, and about how humans see themselves in their environments. What, for instance, is inherited alongside genes? The language of inheritance is lacking. It conflates the biological, the inevitable, with the social. Inheritance is a social process as well as a biological one. Humans tell stories to make sense of the things carried on from the past; and what we mean when we say something is inherited, includes both the social and the biological. The stories about thoroughbreds are powerful precisely because they make the social, the messy, contingent, and constructed past, seem natural. Thoroughbred breeders narrated their animals in various ways using pedigrees, landscapes, animal bodies, standards, and DNA analysis to tell their stories. I argue that a comprehensive understanding of inheritance must accommodate the discourses that informed breeding decisions. These discourses, as much as genes, had real, material effects on both animals and people. As a category, the thoroughbred has remained more or less constant for three hundred years allowing historians to identify how the discourse around thoroughbreds changed over time, place, and political economic regime. My dissertation begins in the desert outside Aleppo at the turn of the eighteenth century in what was then the Ottoman Empire. British traders working for the Levant Company brought Arabian horses back to G

The story goes that all thoroughbreds, unless bred fraudulently, descend from three foundation sires taken to Great Britain from the Levant, the Maghreb, and Arabia in the late-seventeenth and early-eighteenth centuries. That’s just a story, though, and a breed is more a term of art than a scientific fact. Historian William Cronon implored environmental historians to tell “stories about stories about nature.” The stories people told about thoroughbreds over the breed’s three-century history illuminate unspoken assumptions of their society, assumptions about how inheritance works, about how to organize labor, and about how humans see themselves in their environments. What, for instance, is inherited alongside genes? The language of inheritance is lacking. It conflates the biological, the inevitable, with the social. Inheritance is a social process as well as a biological one. Humans tell stories to make sense of the things carried on from the past; and what we mean when we say something is inherited, includes both the social and the biological. The stories about thoroughbreds are powerful precisely because they make the social, the messy, contingent, and constructed past, seem natural. Thoroughbred breeders narrated their animals in various ways using pedigrees, landscapes, animal bodies, standards, and DNA analysis to tell their stories. I argue that a comprehensive understanding of inheritance must accommodate the discourses that informed breeding decisions. These discourses, as much as genes, had real, material effects on both animals and people. As a category, the thoroughbred has remained more or less constant for three hundred years allowing historians to identify how the discourse around thoroughbreds changed over time, place, and political economic regime. My dissertation begins in the desert outside Aleppo at the turn of the eighteenth century in what was then the Ottoman Empire. British traders working for the Levant Company brought Arabian horses back to G

Carbohydrates are the first point of contact in the allergic response pathway, and are thought to heavily regulate the interaction between IgE and mast cells. Several of the groups currently identified to have a role in this process contain N-linked glycans. In this study, various methods for separating N-linked glycans from their peptide backbone were developed to determine which technique released the greatest amount of glycans with the least amount of noise in the resultant mass spectrum. While various mass spectra were obtained, this project focused less on detailing the specifics of the obtained data, but instead sought to determine which method(s) brought about accurate mass spectra (based on previously obtained data) with a high signal-to-noise ratio. Mass spectral data indicates that without proper "pre-separation" techniques, large amounts of high-mass plant material would interfere with analyzing the smaller-mass glycans. Size Exclusion Chromatography (SEC), filtration at the micrometer level, salting out, chemical separations, and mechanical separation via glass beads (all of which can be classified as a "plant material separation") were performed to break down larger pollen protein fragments to smaller units. This was followed by moving on to the "proven method," which worked to separate glycans from their peptide backbone. The "plant material separation" methods are those methods which were tested in order to determine the best way to move forward into the "proven method" of release through permethylation of the glycans. Results indicate that mechanical separation with glass beads followed by the proven method yielded results with a significantly higher amount of released glycans, and less noise in a mass spectrum.

Annual bluegrass (Poa annua L.) and roughstalk bluegrass (Poa trivialis L.) are among the most troublesome grass weeds on golf courses throughout the United States. Herbicides for selective control of these weeds in cool-season fairways are limited and ineffective. Methiozolin is a new isoxazoline herbicide that controls annual bluegrass on putting greens and shows promise for possible weed control in fairways. Kentucky bluegrass (Poa pratensis L.) is among the most common turfgrass species used for golf fairways in the Northern United States and its response to methiozolin has scarcely been tested. A 2.5-yr field study was conducted at four Virginia locations to evaluate methiozolin efficacy for selective annual bluegrass and roughstalk bluegrass control in creeping bentgrass (Agrostis stolonifera L.) or Kentucky bluegrass fairways. Another study evaluated the response of 110 Kentucky bluegrass varieties to three rates of methiozolin. Annual bluegrass has long been presumed to impact putting green trueness, or the ability of the greens canopy to provide a smooth and directionally-consistent ball roll. Although much research has evaluated the impact of greens management on ball roll distance, no peer-reviewed research has evaluated how canopy surface factors, such as weedy annual bluegrass, will influence ball roll direction. Laboratory and field research was conducted to elucidate and overcome experimental errors that may be limiting assessment of ball directional imprecision caused by greens canopy anomalies. Techniques to minimize experimental error were employed in field studies at two Virginia golf courses to determine the influence of annual bluegrass on ball directional imprecision, bounce, and acceleration. Study results suggest that annual bluegrass patches in a creeping bentgrass putting surface can cause subtle increases in ball directional imprecision and bounce but several sources of error must be controlled before these effects can be measured. By usin

The objective of this study was to determine the importance of protein synthesis during germination of white clover (Trifolium repens) and Kentucky bluegrass (Poa pratensis) and to assess the impact of osmopriming on seed germination in the presence of cadmium. Cycloheximide (Cx, 20 and 100 mu M), a translation inhibitor, delayed germination and reduced final germination percentage in both species, although to a higher extent in P. pratensis than in T. repens. This suggests that in white clover, some proteins involved in reserve mobilisation and metabolic activation were already present in mature seeds. Actinomycin-D (Act-D; 20 and 100 mu M) and alpha-amanitin (alpha-Am 20 mu M), both inhibitors of transcription, did not reduce P. pratensis germination, demonstrating that for this species, transcription is not essential for radicle protrusion and that long-lived mRNA are used for initial protein synthesis. In contrast, incised white clover seeds showed delayed germination in presence of alpha-Am, suggesting that expression of some specific genes may help in the first germination steps. Osmopriming (PEG 8,000 60%) improved germination of seeds exposed to 100 mu M Cd but the positive effect of this pretreatment was suppressed (T. repens) or drastically mitigated (P. pratensis) when Act-D or Cx were added to the priming medium. Cadmium reduced alpha- and beta-amylase activities in germinating seeds but osmoprimed seeds exhibited higher activities than unprimed seeds. The presence of inhibitors in the priming medium reduced alpha- and beta-amylase activities. These results suggest that the two studied species differed significantly in the mechanisms occurring during early seed germination and that the beneficial effect of priming requires gene expression and protein synthesis.

To many people, landscape design means choosing the right tree, shrub or flower for a particular place. An important aspect of the landscape often overlooked, however, is the use of turf. Turf often becomes the leftover areas in the landscape rather than an integral design element. Turf is a significant part of successful landscaping. This NebGuide explores the benefits and uses of turf in the landscape.

Biostimulants (BIOS) are non-mineral substances that, when exogenously applied in very small quantities, stimulate the metabolic activity of plants. Past research with biostimulants has not included differing levels of nitrogen fertility or shade as variables. The research presented was designed to explore some interactions between biostimulants and nitrogen fertility on turfgrass grown under several light conditions.

A 3-year study to evaluate the use of plant growth regulators (PGRs) for reducing grounds maintenance costs was conducted at four military installations. Test plots were treated once a year, in the spring, for 3 consecutive years at the following installations: Red River Army Depot, Texas; Fort Leonard Wood, Missouri; Charleston Naval Weapons Station, South Carolina; and Willow Grove Naval Air Station, Pennsylvania. The objectives of this study were to: (a) evaluate the effectiveness of PGR treatments on the dominant turf species at each location; (b) determine the cost-effectiveness of PGR use versus conventional mowing practices; and, (c) provide guidance for incorporating PGRs into installation grounds maintenance programs. Roundup + Oust and Oust + Escort were the most successful treatments evaluated over the 3-year period at the Red River Army Depot. Both treatments provided control of problem broadleaf and grass weed species without adversely affecting the desirable bermudagrass. (Author)

A series of studies were initiated to investigate growth responses of Kentucky bluegrass (Poa praetensis L.) and creeping bentgrass (Agrostis palustris Huds.) to foliar applications of two plant growth regulators (PGR) and/or chelated Fe (Na Fe diethylene triamine pentaacetate). Environmental variables considered were N levels, soil moisture regimes, and saline irrigations. The two materials investigated for PGR properties were a commercial product called Roots (a cold-water extract of seaweed and peat humus fortified with "intermediate metabolites" and thiamine) and the systemic fungicide propiconazole, trade name: (Banner) and chemical name: [1- {(2-(2,4-dichlorophenyl)-4-propyl-l,3-dioxolan-2yl}methyl-l H-1,2,4-triazole]. Fortified seaweed extract (FSE) was applied at 9.3 L/ha, and propiconazole (PPC) was applied at 0.93 L a.i/ha. Each was applied alone or in conjunction with chelated Fe at 0.11 kg a.i/ha. Kentucky bluegrass foliage height, root and shoot dry weight, and several foliar nutrients increased following PGR treatments when grown under either limited soil moisture or saline irrigation. Foliar applications of PGR and/or chelated Fe to creeping bentgrass reduced wilting and evapotranspiration, and increased leaf water status, root strength, and shoot dry matter at two levels of N during and after drought stress.

This NebGuide describes how thatch accumulation damages turfgrass sites, and gives methods for removing accumulations and preventing their reoccurrence. Thatch is a problem on many turfgrass sites. It consists of a tightly intermingled layer of dead and decaying turfgrass tissues derived from stems, roots and leaves.

Weed management treatments were examined as alternatives to conventional chemical herbicides. Site preparation and post-establishment treatments were tested in a randomized complete block factorial design, over two years. There were no site preparation treatment effects of untreated control, glyphosate, acetic acid, and flame weeding. Of the post-establishment treatments, lactic/citric acid and corn gluten meal were ineffective. Sclerotinia minor provided minimal results. Chelated iron, mecoprop/2,4-D/dicamba, and sod reduced the weed cover to < 5%. The efficacy of S. minor on Taraxacum officinale was evaluated three controlled environment studies. Treatments included five temperatures: 12, 16, 20, 24, and 28C and thirteen leaf wetness durations (LWD): 0 to 96 hrs, in 8-hr increments. The main effects (temperature and LWD) and interaction were significant with respect to disease severity over time. A LWD of 48 hrs at 20C and 72 to 96 hrs at 12 and 16oC was required for high disease severity., Funding was provided by the Ontario Ministry of Environment through the Ontario Pesticide Advisory Committee, and Agriculture and Agri-Food Canada through the Clusters Initiative of the Growing Canadian Agri-Innovations Program administered by Vineland Research and Innovations Centre Inc. Also, by Ontario Ministry of Agriculture Food and Rural Affairs through the OMAFRA-University of Guelph Research Agreement.