684 research outputs found
‘Emerald Beauty’ and ‘Emerald Sprite’ Cotoneasters
Cotoneaster (Rosaceae) is a large genus of deciduous and evergreen plants that range from prostrate groundcovers to small trees. The genus is separated into two subgenera including Chaenopetalum with white flowers and Cotoneaster with pink flowers. The former includes common cultivars such as Coral Beauty. Cotoneasters are generally utilitarian shrubs used in mass, often as hedge plants. There has been relatively little modern breeding, although there are many available cultivars. Dirr (2009) noted that beyond Dr. John Ruter at University of Georgia, virtually no breeders in the United States are pursuing efforts to improve and introduce cultivars of this utilitarian genus. Primary challenges for breeders to address are weediness of some species (e.g., C. lacteus), poor growth habit, and susceptibility to fire blight caused by Erwinia amylovora (Contreras 2018). Other groups have documented resistance to fire blight among cotoneasters (Davis and Peterson 1976; Lecomte and Cadic 1993; Losing 1992) or performed some breeding and selection (Bellenot-Kapusta et al. 2002; Persiel and Zeller 1981), but fewer studies have been performed in recent decades
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Evaluation of fruit size and seed number in triploid and tetraploid Malus spp.
Fruit diameter of triploid and tetraploid Malus spp. accessions were evaluated based on ploidy and seed number. Pome size in relation to seed number and ploidy level was evaluated using Tukeys HSD in R. With 95% confidence, pome diameter was not impacted by seed number in these selections (Tukey’s HSD p>0.81). With 95% confidence, triploid and tetraploid fruit were larger than diploid fruit (Tukeys’s HSD p<0.02). With 95% confidence, pome diameter was not different between triploid and tetraploid selections (Tukey’s HSD p=0.97)
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Genome Size, Ploidy, and Base Composition of Wild and Cultivated Acer
Acer is a large and important genus of woody plants most commonly encountered as small to large trees in urban landscapes. Considerable investigation has been devoted to addressing the taxonomy of maples, but little is known about genome sizes across the genus. Relatively more work has been conducted to determine chromosome numbers and ploidy of more species, but much could be gained by expanding knowledge of genome sizes in combination with traditional cytology. Furthermore, base pair (bp) composition may have implications for a species' adaptability and also impacts nucleic acid stability at high temperatures. Our objectives were to determine the genome size of 195 accessions of maples, assign ploidy to each using inference as well as cytology, and determine base composition of a subset of 48 accessions. Most species had small genome sizes (1.4-3.5 pg) with the exception of section Rubra, which contains many polyploids. Holoploid genome sizes ranged from 1.39 to 6.10 pg, with the latter being interpreted as 9x. The mean monoploid genome sizes (1Cx) ranged from 0.43 pg in A. carpinifolium (section Indivisa) to 1.66 pg in A. caudatifolium (section Macrantha); mean monoploid genome sizes were significantly different among sections. Forty-four of the 48 accessions measured using both fluorochromes had greater estimates with 4',6-diamidino-2-phenylindole (DAPI) than propidium iodide (PI). The proportion of the genome composed of guanosine and cytosine (GC%) among the taxa evaluated in this study ranged from just 38.61% to 43.96% and did not appear to be related to ecological adaptability or urban tolerance among these taxa
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‘Oregon Snowflake’ Flowering Currant
Flowering currant (Ribes sanguineum Pursh.), also known as winter currant, is native to the West Coast of the U.S., primarily west of the Coast Range from Southern California north to British Columbia with populations also occurring in Idaho. The species is prized for its early spring flowers in pendulous racemes of 7 to 10 cm in colors including white, pink, and rose-red. Improved cultivars have been selected primarily based on floral traits. These include White Icicle™ (=‘Ubric’) with profuse white flowers on a shrub that reaches 2.5 m high and 1.8 m wide. ‘Pokey’s Pink’ and ‘King Edward VII’ are grown for their clear pink and red flowers, respectively. The growth habit of the species and most of its cultivars are larger than desired and the plants tend to become leggy and exhibit an overall poor form. ‘Oregon Snowflake’ was developed at Oregon State University (OSU) and released by the Oregon Agriculture Experiment Station for its improved plant habit, which is mounding and semi-dwarf as well as its unique leaf shape.This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the American Society for Horticultural Science and can be found at: http://hortsci.ashspublications.org/Keywords: Grossulariaceae, Ornamental plant breeding, Mutagenesis, Ethyl methanesulfonate (EMS), Landscape plant, Ribes sanguineu
Engaging Undergraduate Students in Research
A primary goal of undergraduate education is to provide a comprehensive and diverse educational experience to prepare and promote student success in their professional and personal pursuits. Increased academic success and program connectivity have been demonstrated when undergraduate students are engaged in research early in their degree programs. Despite the known benefits of undergraduates engaging in research, there are challenges associated with conducting undergraduate research programs. Reported barriers include the lack of student knowledge about research methods, lack of preparedness, and lack of student identification and understanding of their specific interests which may not facilitate research ideas and affinity to conduct research. Additional challenges are related to the lack of faculty resources (e.g., time, specific equipment, research space, etc.), the ability to train and supervise undergraduates who may have very limited or no research experience and those students who are true beginners lacking foundational skills. Moreover, involving, engaging, and supporting underrepresented students (e.g., first-generation college students, females, ethnic minorities) in undergraduate research experiences can require different approaches for mentors to be effective. The “Engaging Undergraduate Students in Research” workshop was organized by the Vice Presidents of the American Society for Horticultural Science (ASHS) Research and Education Divisions at the ASHS 2022 Annual Conference in Chicago, IL, USA. The workshop featured three speakers who described their experiences engaging undergraduate students in research. After each speaker provided comments for ≈5 minutes, the workshop attendees self-selected into three breakout groups with the speakers for roundtable discussions related to engaging students in research through coursework, engaging students via formal research projects, and engaging underrepresented students in research. After the breakout group discussions, a summary was given by each group, and whole group discussions and comments were facilitated. This is a summary of the information discussed and shared during the workshop, along with information that can assist faculty with developing and implementing undergraduate research experiences
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Creation of Hexaploid and Octaploid Zoysiagrass Using Colchicine and Breeding
Zoysiagrasses (Zoysia Willd.) are a slow-growing, tetraploid (2n = 4x = 40) turfgrass that can be successfully managed with less input than many other warm-season grasses. Despite extensive genetic and morphological variation, genotypes with the ability to recuperate quickly from damage are rare. Therefore, a long-term effort to increase vegetative growth rates was initiated during 2009 by first studying the effectiveness of six colchicine seed treatments and breeding for manipulating the ploidy level of 'Zenith' zoysiagrass. Colchicine-treated seedlings were screened using flow cytometry for genome size changes. Four putative octaploids and one cytochimera were identified. Average stomata length of the four colchicine-induced putative octaploids were 28% larger than that of Zenith, but the cytochimera's stomata length was not altered. Pollen diameter of the four putative octaploids was larger than that of Zenith and the cytochimera. Pollen stainability was relatively unchanged by the colchicine treatments. Further self-and cross-pollination of 09-TZ-103 (putative M₀ octaploid) led to the development and verification of M₁ octaploid and M₁ hexaploid genotypes. These results support that DNA content of the L-I (epidermis), L-II (germ line), and L-III (adventitious roots) histogenic layers of Zoysia can be manipulated with colchicine and breeding. Future evaluation of the turfgrass performance of these polyploids is the next step in determining the value of this breeding procedure for improvement of zoysiagrass.Keywords: Flow cytometry, Chromosome numbers, Establishment rates, Stolon growth, Annual ryegrass, Cultivars, Registration, Nuclear DNA content, Genetic control, Ploidy leve
Using Rheo-Small-Angle Neutron Scattering to Understand How Functionalised Dipeptides Form Gels
We explore the use of rheo-small-angle neutron scattering as a method to collect structural information from neutron scattering simultaneously with rheology to understand how low-molecular-weight hydrogels form and behave under shear. We examine three different gelling hydrogel systems to assess what structures are formed and how these influence the rheology. Furthermore, we probe what is happening to the network during syneresis and why the gels do not recover after an applied strain. All this information is vital when considering gels for applications such as 3D-printing and injection
Climate-Ready Landscape Plants: Garden Roses Trialed at Reduced Irrigation Frequency in Utah, USA
Increased urban and suburban populations in the arid western United States have resulted in more water demand; however, water availability in the region has become limited because of inadequate precipitation. Recent droughts have led to restrictions on irrigating landscape plants. Garden rose (Rosa ×hybrida) is commonly used as flowering plants in residential landscapes, but its drought tolerance has not been widely studied. The objective of this study was to determine the impact of reduced irrigation frequency on visual quality, plant growth, and physiology of five garden rose cultivars, including ChewPatout (Oso Easy® Urban Legend®), Meibenbino (Petite Knock Out®), MEIRIFTDAY (Oso Easy® Double Pink), Overedclimb (Cherry Frost™), and Radbeauty (Sitting Pretty™). Twenty-four plants of each rose cultivar were established in a trial plot at Utah Agricultural Experiment Station Greenville Research Farm (North Logan, UT, USA) in Summer 2021. Plants were randomly assigned to one of three deficit irrigation treatments for which irrigation frequencies were calculated using 80% reference evapotranspiration (ETO) (high), 50% ETO (medium), and 20% ETO (low). The total volumes of irrigation water applied to each plant were 345.6, 172.8, and 43.2 L for the high, medium, and low irrigation frequencies, respectively, during the deficit irrigation trial from 12 May to 30 Sep 2022. Root zones were wetted more frequently as irrigation frequency increased from low to high irrigation frequencies. Decreased irrigation frequency increased the number of visibly wilted and damaged leaves on all rose cultivars. However, only ‘Meibenbino’ and ‘MEIRIFTDAY’ exhibited a reduction in overall appearance under decreased irrigation frequency. The relative growth indices of both ‘Meibenbino’ and ‘MEIRIFTDAY’ decreased by 6%, whereas the dry weights of their leaves decreased by 37% and 36%, respectively, as irrigation decreased from high to low frequencies. Roses in this study appeared to decrease stomatal conductance up to 51% when irrigation decreased from high to low frequencies, or when air temperature increased. ‘Meibenbino’ and ‘MEIRIFTDAY’ exhibited unacceptable overall appearance, growth reduction, and higher leaf–air temperature differences, and they were less tolerant to reduced irrigation. Although the ‘Radbeauty’ maintained plant growth under the reduced irrigation frequency, the large leaf size led to a more visibly wilted appearance and the potential for heat stress, thus impairing visual quality. ‘ChewPatout’ and ‘Overedclimb’ were most tolerant to deficit irrigation at 20% ETO and maintained plant growth with acceptable visual quality and lower leaf temperatures when they received one irrigation during the growing season
Improved Vascular Engraftment and Graft Function After Inhibition of the Angiostatic Factor Thrombospondin-1 in Mouse Pancreatic Islets
OBJECTIVE—Insufficient development of a new intra-islet capillary network after transplantation may be one contributing factor to the failure of islet grafts in clinical transplantation. The present study tested the hypothesis that the angiostatic factor thrombospondin-1 (TSP-1), which is normally present in islets, restricts intra-islet vascular expansion posttransplantation
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