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Management of Powdery Mildew on Ninebark Using Sanitizers, Biorational Products, and Fungicides
Get PDFNinebark (Physocarpus opulifolius) is a popular ornamental shrub and considered a hardy and tough plant that can thrive in different environmental conditions and resist diseases. However, powdery mildew, caused by Podosphaera physocarpi, can severelyaffect ninebark, deteriorating the ornamental value and making them unmarketable. Only a few studies have been done in managing powdery mildew of ninebark. The current study focuses on evaluating and identifying effective products (sanitizers, biorational products, and fungicides) for the management of powdery mildew disease of ninebark. A total of 12 treatments, including nontreated control, were studied. The experiment was arranged in randomized complete block design with four-single ‘Mindia Coppertina®’ ninebark plant per treatment and repeated twice. Powdery mildew disease severity, growth parameters, and phytotoxicity were assessed in the study. All treatments significantly reduced the powdery mildew disease severity and disease progress [area under disease progress curve (AUDPC)] compared with the nontreated control. The treatments, such as azoxystrobin + benzovindiflupyr at 0.17 and 0.23 g·L–1 total active ingredients (a.i.) applied, chlorothalonil + propiconazole at 1.12 mL·L–1 total a.i. applied, azoxystrobin + tebuconazole at 0.11 and 0.16 g·L–1 total a.i. applied, and giant knotweed extract [Reynoutria sachalinensis (0.5 mL·L–1 total a.i. applied)] were the most effective treatments in reducing disease severity and disease progress in both trials. The treatments had no significant effects on the plant growth parameters such as height and width. In Expt. 2, azoxystrobin + benzovindiflupyr and hydrogen peroxide + peroxyacetic acid treated plants showed the low level of phytotoxic symptoms. The phytotoxicity of these two treatments in Expt. 2 could be related to higher environmental temperature during the experimental period
Soil extracellular oxidases mediated nitrogen fertilization effects on soil organic carbon sequestration in bioenergy croplands
Get PDFNitrogen (N) fertilization significantly affects soil extracellular oxidases, agents responsible for decomposition of slow turnover and recalcitrant soil organic carbon (SOC; e.g., lignin), and consequently influences soil carbon sequestration capacity. However, it remains unclear how soil oxidases mediate SOC sequestration under N fertilization, and whether these effects co-vary with plant type (e.g., bioenergy crop species). Using a spatially explicit design and intensive soil sampling strategy under three fertilization treatments in switchgrass (SG: Panicum virgatum L.) and gamagrass (GG: Tripsacum dactyloides L.) croplands, we quantified the activities of polyphenolic oxidase (PHO), peroxidase (PER), and their sum associated with recalcitrant C acquisition (OX). The fertilization treatments included no N fertilizer input (NN), low N input (LN: 84 kg N ha−1 year−1 in urea), and high N input (HN: 168 kg N ha−1 year−1 in urea). Besides correlations between soil oxidases and SOC (formerly published), both descriptive and geostatistical approaches were applied to evaluate the effects of N fertilization and crop type on soil oxidases activities and their spatial distributions. Results showed significantly negative correlations between soil oxidase activities and SOC across all treatments. The negative relationship of soil oxidases and SOC was also evident under N fertilization. First, LN significantly depressed oxidases in both mean activities and spatial heterogeneity, which corresponded to increased SOC in SG (though by 5.4%). LN slightly influenced oxidases activities and their spatial heterogeneity, consistent with insignificant changes of SOC in GG. Second, HN showed trends of decrease in soil oxidase activities, which aligned with the significantly enhanced SOC in both croplands. Overall, this study demonstrated that soil oxidase activities acted as sensitive and negative mediators of SOC sequestration in bioenergy croplands and optimizing fertilizer use particularly in switchgrass cropland can improve for both carbon sequestration and environmental benefit
Response of Cover Crops to Phytopythium vexans, Phytophthora nicotianae, and Rhizoctonia solani, Major Soilborne Pathogens of Woody Ornamentals
Get PDFManagement of plant diseases is a subject of concern for researchers as well as growers. Different management practices are being developed and used to combat the rising number of plant pathogens, which threaten nursery crop production. Use of cover crops for sustainable management of soilborne diseases is being explored as an alternative strategy to the chemicals. However, the potential threat of these cover crops acting as a secondary host of these devastating soilborne pathogens has not been described. We studied the response of the major cover crops being used by woody ornamental growers in the Southeastern United States to Phytopythium vexans, Phytophthora nicotianae, and Rhizoctonia solani in greenhouse conditions to identify the effective cover crops that can be used in a nursery field production system. Data related to post-emergence damping-off and plant growth parameters (plant height increase and fresh weight) were recorded. Similarly, cover crop roots were assessed for root rot disease severity using a scale of 0–100% roots affected. Among the tested cover crops, the grass cover crops triticale (×Triticosecale Wittm. ex A. Camus.), annual ryegrass (Lolium multiflorum L.), Japanese millet (Echinochloa esculenta (A. Braun) H. Scholz), and the legumes Austrian winter pea (Pisum sativum var. arvense (L.) Poir) and cowpea ‘Iron and Clay’ (Vigna unguiculata (L.) Walp.), showed lower root rot disease severity and post-emergence damping-off in the soil inoculated with P. nicotianae, R. solani, or P. vexans compared to the other crops. Since these cover crops can act as non-host crops and benefit the main crop in one way or another, they can be used in the production system. Further research is recommended to evaluate their performance in a natural field setting
Genetic variability and genome-wide association analysis of flavor and texture in cooked beans (Phaseolus vulgaris L.)
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Cooked bean flavor and texture vary within and across 20 Andean seed types; SNPs are significantly associated with total flavor, beany, earthy, starchy, bitter, seed-coat perception, and cotyledon texture. Abstract
Common dry beans are a nutritious food recognized as a staple globally, but their consumption is low in the USA. Improving bean flavor and texture through breeding has the potential to improve consumer acceptance and suitability for new end-use products. Little is known about genetic variability and inheritance of bean sensory characteristics. A total of 430 genotypes of the Andean Diversity Panel representing twenty seed types were grown in three locations, and cooked seeds were evaluated by a trained sensory panel for flavor and texture attribute intensities, including total flavor, beany, vegetative, earthy, starchy, sweet, bitter, seed-coat perception, and cotyledon texture. Extensive variation in sensory attributes was found across and within seed types. A set of genotypes was identified that exhibit extreme attribute intensities generally stable across all three environments. seed-coat perception and total flavor intensity had the highest broad-sense heritability (0.39 and 0.38, respectively), while earthy and vegetative intensities exhibited the lowest (0.14 and 0.15, respectively). Starchy and sweet flavors were positively correlated and highest in white bean genotypes according to principal component analysis. SNPs associated with total flavor intensity (six SNPs across three chromosomes), beany (five SNPs across four chromosomes), earthy (three SNPs across two chromosomes), starchy (one SNP), bitter (one SNP), seed-coat perception (three SNPs across two chromosomes), and cotyledon texture (two SNPs across two chromosomes) were detected. These findings lay a foundation for incorporating flavor and texture in breeding programs for the development of new varieties that entice growers, consumers, and product developers alike
Observations with the Differential Speckle Survey Instrument. X. Preliminary Orbits of K-dwarf Binaries and Other Stars
Get PDFThis paper details speckle observations of binary stars taken at the Lowell Discovery Telescope, the WIYN telescope, and the Gemini telescopes between 2016 January and 2019 September. The observations taken at Gemini and Lowell were done with the Differential Speckle Survey Instrument (DSSI), and those done at WIYN were taken with the successor instrument to DSSI at that site, the NN-EXPLORE Exoplanet Star and Speckle Imager (NESSI). In total, we present 378 observations of 178 systems, and we show that the uncertainty in the measurement precision for the combined data set is ∼2 mas in separation, ∼1°–2° in position angle depending on the separation, and ∼0.1 mag in magnitude difference. Together with data already in the literature, these new results permit 25 visual orbits and one spectroscopic-visual orbit to be calculated for the first time. In the case of the spectroscopic-visual analysis, which is done on the ternary star HD 173093, we calculate masses with a precision of better than 1% for all three stars in that system. Twenty-one of the visual orbits calculated have a K dwarf as the primary star; we add these to the known orbits of K-dwarf primary stars and discuss the basic orbital properties of these stars at this stage. Although incomplete, the data that exist so far indicate that binaries with K-dwarf primaries tend not to have low-eccentricity orbits at separations of one to a few tens of astronomical units, that is, on solar system scales
Undergraduate Catalogue 2019- 2021
Get PDFhttps://digitalscholarship.tnstate.edu/undergraduatecatalogues/1068/thumbnail.jp
