Latest Reports and Publications

June, 2015

HortTechnology, June 2015, 25(3).
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Abstract
Mary Jane Clark and Youbin Zheng, 2015. The objective of this study was to determine the optimal controlled release fertilizer (CRF) application rates or ranges for the production of five 2-gal nursery crops. Plants were evaluated following fertilization with 19N–2.6P–10.8K plus minors, 8–9 month CRF incorporated at 0.15, 0.45, 0.75, 1.05, 1.35, and 1.65 kg.m-3 nitrogen (N). The five crops tested were bigleaf hydrangea (Hydrangea macrophylla), ‘Green Velvet’ boxwood (Buxus ·), ‘Magic Carpet’ spirea (Spiraea japonica), ‘Palace Purple’ coral bells (Heuchera micrantha), and rose of sharon (Hibiscus syriacus). Most plant growth characteristics (i.e., growth index, plant height, leaf area, and shoot dry weight) were greater in high vs. low CRF treatments at the final harvest. Low CRF rates negatively impacted overall appearance and marketability. The species-specific CRF range recommendations were 1.05 to 1.35 kg.m-3 N for rose of sharon, 0.75 to 1.05 kg.m-3 N for ‘Magic Carpet’ spirea, and 0.75 to 1.35 kg.m-3 N for bigleaf hydrangea and ‘Green Velvet’ boxwood, whereas the recommended CRF rate for ‘Palace Purple’ coral bells was 0.75 kg.m-3 N. Overall, species-specific CRF application rates can be used to manage growth and quality of containerized nursery crops during production in a temperate climate.

June, 2015

Journal of Environmental Horticulture, June 2015, 33(2): 66-75.
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Abstract
Mary Jane Clark and Youbin Zheng, 2015. To determine the response of container-grown shrubs to controlled-release fertilizer (CRF) rate when grown in a temperate climate, Polyon® 19–04–10 + Minors, an 8–9 month CRF, was incorporated into growing substrates for ‘Gro-Low’ fragrant sumac (Rhus aromatica Aiton), ‘Goldmound’ spirea (Spiraea × bumalda Burv.) and ‘Bloomerang’® purple lilac (Syringa × ‘Penda’) transplants.

Ontario horticulture research priority report 2015
May, 2015

Features

  • Edible horticulture
  • Ornamental horticulture
Species-specific fertilization can benefit container nursery crop production
April, 2015

Canadian Journal of Plant Science, Published March 2015.
The article is available here to individuals with subscription.

Abstract
Clark, M. J. and Zheng, Y. 2015. Species-specific fertilization can benefit container nursery crop production. Can. J. Plant Sci. 95: 251–262. To determine the responses of six container-grown shrub species to different controlled-release fertilizer (CRF) application rates, plant growth and root-zone traits were evaluated following fertilization with Polyon® 16–6–13, 5–6 month CRF incorporated at 0.60, 0.89, 1.19, 1.49 and 1.79 kg m−3 N. The six species tested at a southwestern Ontario, Canada, nursery were Cornus stolonifera ‘Flaviramea’ (yellow-twig dogwood), Euonymus alatus ‘Compactus’ (dwarf winged euonymus), Hydrangea paniculata ‘Grandiflora’ (Pee Gee hydrangea), Physocarpus opulifolius ‘Nugget’ (Nugget ninebark), Spiraea japonica ‘Magic Carpet’ (Magic Carpet spirea), Weigela florida ‘Alexandra’ (Wine and Roses weigela). Different species responded differently to the CRF rates applied. For the majority of species at the final harvest, growth index, plant height, canopy area, leaf area and above-ground dry weight were greater in high vs. low CRF rates; however, different species had different optimal CRF application rates or ranges: 1.49 kg m−3 N for Hydrangea and Spiraea, 1.19 kg m−3 N for Weigela, 1.19 to 1.49 kg m−3 N for Cornus and Physocarpus, and ≤0.60 kg m−3 N for Euonymus. Based on these species-specific optimal fertilizer rates or ranges, growers can group plant species with similar fertilizer demands, thereby reducing fertilizer waste and maximizing plant production.

April, 2015

Food Quality and Preference, 2015, In Press
The article is available here at a cost

Abstract: A. Grygorczyk, S. Mhlanga, I. Lesschaeve. Color is often found to be the most important factor driving consumer purchase decisions for flowers. However due to the sheer number of flower color options available, pinpointing which flower shades to aim for in a breeding program is a complex task. Discussions with local growers revealed discrepancies between color preferences previously identified and actual consumer demand. The present work examines this in further detail by applying two methods of testing consumer flower color preference with the same panel of consumers: conjoint analysis using color categories and a follow-up question asking consumers to pick their 3 most preferred colors from a chart of 60 colors. Consumers were found to have different tolerance ranges for shades across color categories. Consumers have a wide range of tolerance for red colors, making this a safe target as nearly all shades of red tested were well liked by consumers. By contrast, in the yellow category there was one very high performing shade, with consumer preference dropping off sharply with any deviation from this shade. While this particular shade of yellow could potentially be highly successful with consumers, it is a riskier target as breeders would have a narrow range of tolerance in shade variation to achieve consumer success. This study presents a new understanding of consumer preference as it suggests that consumers exhibit not only preference intensity for sensory stimuli, but also a tolerance range for variations on the stimulus. Interestingly, tolerance ranges are not consistent across categories of sensory stimuli (e.g. color categories).

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