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Improving abiotic and biotic stress tolerance in floriculture crops

South, Kaylee
http://rave.ohiolink.edu/etdc/view?acc_num=osu1595499762154056

Abstract Details

2020, Doctor of Philosophy, Ohio State University, Horticulture and Crop Science.
An intensive production system is used to produce greenhouse floriculture crops, marketed for their flowers and attractive foliage. Chemical, environmental, and cultural methods are used to manage biotic and abiotic stresses during production. Additional tools are needed by growers because of growing concerns around the negative impact of plant production on humans and the environment. The objective of this research was to evaluate potential tools to improve floriculture crop resilience under stress during production and post-production. Botrytis cinerea causes disease in most major greenhouse crops and is resistant to several fungicides. Additional control methods, like plant growth promoting bacteria (PGPB) that can improve plant performance by increasing plant resilience to stress are needed. A collection of 60 bacterial strains was evaluated in a dual culture assay and an initial greenhouse trial with Petunia × hybrida `Carpet Red Bright’ to identify strains for the biocontrol of B. cinerea. Daily flower disease severity ratings were used to select seven strains that were evaluated in the validation greenhouse trial. Three Pseudomonas strains were selected for the greatest reduction in B. cinerea infection. The efficacy of PGPB and the plant’s susceptibility to B. cinerea were affected by fertilization. Petunia × hybrida `Carpet Red Bright’ was treated with bacteria or a commercial biocontrol product and fertilized with synthetic chemical or organic fertilizer at a low or high rate. Measured plant growth and flower disease severity revealed that plants with the high rate synthetic fertilizer were the largest and had the lowest disease severity. Reduction of disease severity varied between bacterial and fertilizer treatment combinations. Plants treated with one bacterium had reduced disease severity at the high rate synthetic chemical fertilizer but not at the low rate organic fertilizer. Specific fertility programs provide crops with needed macro and micronutrients, but overuse can lead to negative environmental impacts, plant disorders, and higher susceptibility to other stresses. Application of PGPB can improve floriculture plant performance grown under low fertility. Ninety-four bacterial isolates identified from the rhizosphere of ornamental plants were evaluated in P. hybrida `Picobella Blue’ grown under low fertility, and 15 isolates were selected for increasing plant performance. Whole-genome sequencing was used to determine their identity and bacteria were evaluated again under low fertility along with untreated plants receiving higher fertilizer rates. Three bacteria were selected as top performers for increases in flowering, vegetative health, and vegetative quality. Over- or under-watering is a common stress for Phalaenopsis orchids once the orchid reaches the consumer, but to avoid water stress, ice cube irrigation is recommended. Orchid health was evaluated after irrigation with either ice cubes or room temperature water. Orchids grown in bark media did not have a reduction in display life or health when irrigated with ice cubes. Utilizing novel tools, like PGPB or ice cube irrigation, during production or post-production is an important move toward improving floriculture crop performance. These tools can be used to improve floriculture crop resilience to biotic or abiotic stresses and establish additional sustainable practices for the greenhouse industry.
Michelle Jones (Advisor)
David Francis (Committee Member)
Francesca Hand (Committee Member)
Pablo Jourdan (Committee Member)
Matthew Kleinhenz (Committee Member)
297 p.
Agriculture; Horticulture
Botrytis cinerea; gray mold; botrytis blight; biocontrol; plant growth promoting bacteria; PGPB; plant growth promoting rhizobacteria; PGPR; fertilizer; bedding plants; ornamentals; greenhouse production; horticulture; Phalenopsis; orchid; ice cubes

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Citations

  • South, K. (2020). Improving abiotic and biotic stress tolerance in floriculture crops [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1595499762154056

    APA Style (7th edition)

  • South, Kaylee. Improving abiotic and biotic stress tolerance in floriculture crops. 2020. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1595499762154056.

    MLA Style (8th edition)

  • South, Kaylee. "Improving abiotic and biotic stress tolerance in floriculture crops." Doctoral dissertation, Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1595499762154056

    Chicago Manual of Style (17th edition)

osu1595499762154056
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This open access ETD is published by The Ohio State University and OhioLINK.