Browsing by Author "Gouker, Fred E."

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    Analyzing the structural shifts in U.S. boxwood production due to boxwood blight
    Hall, Charles R.; Hong, Chuanxue; Gouker, Fred E.; Daughtrey, Margery (Horticultural Research Institute, 2021-09-01)
    The purpose of this study is to examine the changes in the sales of boxwood (Buxus spp.) that have occurred in boxwood production states. We theorize that some of the shifts in production areas over the period from 2009 to 2019 have been impacted by the introduction of boxwood blight into the United States. Boxwood blight (Calonectria pseudonaviculata) was first observed in the U.S. in 2011 by plant pathologists in 8 states: Connecticut, Maryland, Massachusetts, New York, North Carolina, Oregon, Rhode Island, and Virginia. The disease has now been seen in 30 states plus the District of Columbia. The data used for this analysis is from the Census of Horticultural Specialties (CHS), a survey administered by the United States Department of Agriculture, National Agricultural Statistics Service (USDA-NASS) every five years. The findings from this analysis of the Census of Horticultural Specialties data from 2009 to 2019 indicate that there were already shifts occurring in boxwood markets prior to the introduction of boxwood blight. However, boxwood blight has exacerbated the supply chain challenges for green industry participants by limiting production in certain areas of the country, increasing the costs of producing boxwood compared to other evergreen shrubs, and perhaps dampening the demand from what might have been without the existence of the blight.
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    Cultivars and Production Environments Shape Shoot Endophyte Profiles of Boxwood with Different Blight Resistance
    Li, Xiaoping; Weiland, Jerry E.; Ohkura, Mana; Luster, Douglas G.; Daughtrey, Margery L.; Gouker, Fred E.; Chen, Gloria; Kong, Ping; Hong, Chuanxue (American Phytopathological Society, 2024-12)
    Phyllosphere colonizers, including bacteria and fungi, are critical for plant growth and health. However, how they are affected simultaneously by the host plant cultivar, local environment, and agricultural practices was not well understood. We used boxwood, an iconic landscape plant and a major evergreen shrub crop in the United States nursery industry, as a model plant and sequenced 16S rRNA and ITS amplicons to examine the assemblages of endophytic bacteria and fungi in the shoots of four cultivars representing three levels of boxwood blight resistance under two distinct climates and production systems in Oregon and Virginia. Cultivar and local environment were the two main drivers shaping the composition and structure of the boxwood endophytic microbial community, particularly the fungal community. Three bacterial and seven fungal genera were consistently identified with high prevalence and abundance as the core taxa from four cultivars and two locations across three sampling times. The microbial composition varied among the levels of boxwood blight resistance, and taxa specific to the tolerant cultivar were fewer compared to the susceptible one. Identification of these microbial indicators, along with the core taxa, is foundational for developing a microbiome-based plant breeding program and a systems approach to improve boxwood health and production under a changing climate. [Formula: see text]