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  • Author or Editor: Ryan N. Contreras x
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Ornamental grasses such as fountaingrass or napiergrass, collectively called pennisetums, belong to the genus Pennisetum, which is a diverse genus with over 80 species adapted to a wide range of climatic regions and known for its drought tolerance. Breeding efforts have led to improvements such as more intense purple foliage color, disease resistance, and apparent sterility. These improved forms have been developed and tested in the eastern United States. The objective of this research was to evaluate container and field performance of seven new complex hybrid pennisetums in the Pacific northwestern United States. Two completely randomized experiments with three replications were conducted over 2 years (2010 and 2011) at two locations. We selected seven trispecific hybrid pennisetums resulting from interploid and interspecific crossing that were given accessions Tift 5, Tift 6, Tift 10, Tift 11, Tift, 13, Tift 15, and Tift 26. Experiment 1 evaluated container performance in Corvallis, OR, while Expt. 2 evaluated field performance in Aurora, OR. Size index (SI), growth form rating, and color rating were collected and analyzed separately by location. In the container study, significant differences were observed among selections for growth form in 2010 and color ratings in both 2010 and 2011. In 2010, Tift 6, Tift 11, Tift 13, and Tift 15 had the highest growth form rating. For color rating, Tift 5, Tift 10, and Tift 26 were among the four highest rated selections in both years. In the field study, Tift 5, Tift 10, Tift 11, and Tift 26 had the highest SI when data were pooled over the 2 years, but all selections reached acceptable size for landscape use during both years of the study. Similarly, there were color differences among selections with Tift 5, Tift 10, Tift 15, and Tift 26 being highest rated. None of the selections survived below winter temperatures of −5 °C at either location during either year of the study. Our evaluations indicate that these selections have potential in the Pacific northwestern United States as annuals. Differences in complex hybrid pennisetums were observed in SI, growth form rating, and color rating. These differences demonstrated the variation among selections and will allow producers to choose desired traits based on market preference.

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‘Schipkaensis’ common cherrylaurel (Prunus laurocerasus) is an important nursery crop across the United States. In our breeding efforts to reduce shot-hole symptoms and weediness, we have created chromosome doubled forms of this cultivar. Vegetative propagation is an important factor in nursery production, and we have found no studies that have looked at comparative adventitious rooting of stem cuttings using induced polyploids. The objective of this research was to determine if rooting ability varied between these two ploidy levels. Semihardwood stem cuttings from wild-type (22x) and polyploid (44x) ploidy levels were taken at the end of July 2015 and the beginning of July 2016. Cuttings were dipped in 1030 ppm (0.10%) indole-3-butyric acid (IBA) and 660 ppm (0.066%) 1-naphthaleneacetic acid (NAA) before being set in rooting substrate. After 1 month, cuttings were removed from substrate and data collected. Data included; rooting percentage, root number per rooted cutting, average root length, and total root length. In 2015, 88% of the cuttings from the 44x plants and 63% of the cuttings from the 22x plants rooted. In 2016, 100% of cuttings from both ploidy levels rooted. In both years, average root length and total root length were similar between ploidy levels; however, cuttings from 22x plants generally had more roots than those from 44x. Chromosome-doubled ‘Schipkaensis’ common cherrylaurel rooted effectively, and produce transplantable cuttings similar to the standard ploidy.

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New technologies such as online databases, interactive dichotomous keys, and online courses have changed the way some plant identification courses are delivered. These changing resources may create discrepancies between traditional instruction of landscape plant materials courses and the way modern students learn, which may result in students not meeting their potential. However, what resources students are using to study plant materials is unclear. We investigated the relationship between learning styles, study habits, and performance of students during two terms of woody landscape plant materials courses. To assess these relationships, we determined the characteristics of the participants and their preferred study method throughout the duration of the term as well as correlations between 1) preferred learning styles and performance, 2) preferred learning styles and preferred study method, and 3) performance and preferred study method. The participants in this study (n = 31) consisted of 14 males and 17 females. Of the 31 participants, 3 were freshmen, 3 were sophomores, 16 were juniors, 7 were seniors, and 2 were graduate students. Based on preference scores for learning style, 15 students were identified as visual learners, 3 as auditory, and 13 as kinesthetic learners. No significant relationships were observed between preferred learning style and performance or between preferred learning style and preferred study method. The two preferred study methods were using branch samples collected by the instructor and notecards created by students. No relationship existed between preferred study method and performance in the course. Our study provides information on study methods of woody plant identification students enrolled in a site-based course. We did not observe statistically significant relationships among preferred learning style, preferred study method, and course grade, but anecdotal evidence indicated students who prepared their own study aids by making notecards scored better in these courses.

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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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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.

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