About

John Dole is a Professor in the Department of Horticultural Science at NC State University, located in Kilgore Hall. His program focuses on the production and postharvest physiology of floriculture crops, with particular emphasis on working with cut flowers, poinsettias, and vegetatively-propagated cuttings. He teaches courses including HS 705, Physiology of Flowering, and is a founding member of Seed Your Future, an organization dedicated to inspiring careers in horticulture. Dole serves as the Executive Advisor for the Association of Specialty Flower Growers and is a co-PI for the FFAR Fellows program, which is a leading professional development initiative for PhD students in Agriculture and the Life Sciences. His research contributions include postharvest management of chrysanthemums, the use of biostimulants to improve growth and quality of ornamental plants, and extending the longevity of cut flowers through various handling procedures. He holds a Ph.D. in Horticulture with a focus on plant physiology from the University of Minnesota and a B.S. in Horticulture from Michigan State University.

Research topics

• Horticulture
• Biology
• Botany
• Chemistry
• Economics
• Business
• Geography
• Mathematics
• Agricultural economics
• Medicine

Selected publications

• Postharvest Management of Chrysanthemum

  Crop production science in horticulture. · 2026-02-23

  book-chapter1st authorCorresponding

  Chrysanthemums (Chrysanthemum morifolium) are one of the world’s most important cut flowers, potted flowering plants, and garden plants due to their stunning array of flower colors, forms, and sizes as well as a long postharvest life. Many factors affect postharvest life, starting with selecting long-lasting cultivars, especially in regard to resistance to leaf yellow or necrosis. Optimum relative humidity, light and nutrition during production, and proper harvest stage are needed for a long shelf life. After harvest, several factors should be considered including minimizing ethylene, ensuring stems and plants are well hydrated, and preventing mechanical damage and diseases. Maintaining low temperatures, 0–1°C, from harvest to sale and using proper bucket and vase solutions is especially critical for cut flowers. The future is bright for chrysanthemums with continually improved breeding, sustainable production practices, improved transport logistics, such as sea transport, and new handling protocols, such as subzero storage of cut flowers.

  PublisherDOI

• VARIOUS POSTHARVEST HANDLING PROCEDURES EXTEND LONGEVITY OF CUT Gerbera jamesonii STEMS

  The Journal of Animal and Plant Sciences · 2025-06-11

  articleOpen access

  Efficient postharvest handling plays a pivotal role in preserving stem quality, which demands testing novel and cost-effective techniques for extending the postharvest longevity of cut stems. Postharvest management practices are crucial to improve cut stems longevity. Therefore, a study was conducted to evaluate and standardize postharvest handling protocols for cut gerbera stems including harvest stage, handling procedures, vase water quality, pulsing and vase preservatives, floral foam, storage methods and durations and packaging materials. Results demonstrated that stems harvested at partially opened bloom stage had the longest vase life (16.6 d) followed by closed bud stage (15.2 d). Stems kept in distilled water remained fresh for longer (8.4 d vase life) compared to tap water (5.0 d) and canal water (3.2 d). Tap water affected gerbera stems negatively with highest petal necrosis (100%) and highest reduction in flower quality (8.1) among tested water sources. Stems handled wet (in buckets containing water) had longest vase life (15.7 d) with least change in flower quality (7.2). Gerbera stems pulsed with 2% sucrose + 100 mg L-1 aluminum sulphate for 24 h exhibited longest vase life (11.4 d) followed by lemon/lime soda (7 Up) + distilled water (11.2 d). Placement of cut stems in lemon/lime soda + distilled water (33:66) until termination (vase preservatives) exhibited longest vase life (15.9 d) followed by 2% sucrose along with 150 mg L-1 citric acid and 100 mg L-1 aluminum sulphate (15.3 d, respectively) and were statistically similar. Chrysal Clear Professional flower food along with floral foam kept stems fresh and marketable for 16.9 d, while for 15.6 d without foam. Stems stored wet (in buckets containing water) or in a floral box along with 1-MCP card for 2 days exhibited longest vase life (7.8 d and 7.3 d, respectively). Flower heads packed in floral box after being wrapped in polythene sleeves and plugged with cotton tube at base exhibited the longest vase life (6.5 d) when stored for 2 days compared to control (unpacked and unstored stems). In summary, gerbera stems may be harvested at partially opened bloom stage, handled in water (wet) from harvest to marketing and preferably handled in distilled water, pulsed with 2% sucrose + 150 mg L-1 citric acid, 2% sucrose + 100 mg L-1 aluminum sulphate or lemon/lime soda + distilled water (50:50) for 24 h or kept continuously in lemon/lime soda + distilled water (33:66) until termination. Moreover, stems may be kept with floral foam and stored in buckets containing water (wet) preferably with 1-MCP card for two days and packed in floral boxes lined with polythene sleeves to keep stems fresh for longer durations. Keywords: Floral foam, homemade preservatives, ion leakage, packaging, storage methods, termination symptoms.

  PublisherDOI

• Biostimulants improve growth, yield and quality of Eustoma grandiflorum L. and Matthiola incana L.

  Ornamental Horticulture · 2025-01-01

  articleOpen access

  Abstract Lisianthus (Eustoma grandiflorum L.), a member of family Gentianaceae, and stock (Matthiola incana L.), a member of family Brassicaceae, are extensively grown as cut flowers globally and are also gaining popularity in Pakistani markets in recent years. This study was aimed at evaluating the efficacy of selected biostimulants on improving the growth, yield, and quality of lisianthus and stock at Floriculture Research Area, Institute of Horticultural Sciences, University of Agriculture, Faisalabad, during 2022-2023. The experiment was laid out individually for each species to elucidate the effects of three different products, viz. Isabion (3 mL L-1), Humic acid (0.4%) and Corteva XYZ (3 mL L-1). Both experiments were laid out in randomized complete block design (RCBD) with three replications of 20 plants each. Biostimulants were applied at 3 mL L-1 Isabion and Corteva XYZ, while 0.4% humic acid, which were sprayed three times at fifteen days interval until runoff on each species starting after fifteen days of transplanting. Results demonstrated significant differences among treatments for both Eustoma grandiflorum L. and Matthiola incana L. Lisianthus utilized least production time (59 days) when sprayed with Corteva XYZ, while in stock Isabion application produced earlier flowers (75.6 days) compared to other tested treatments. Isabion application significantly increased plant height (60.3 and 79.6 cm), floret diameter (39.8 and 4.2 mm), stem diameter (4.0 and 6.1 mm), stem fresh weight (77.6 and 86.1 g), stem dry weight (16.9 and 15.1 g) and vase life (8.8 and 7.5 days) of lisianthus and stock, respectively. Greatest leaf area (27.7 and 32.9 cm2) was recorded when plants were supplied with Corteva XYZ for lisianthus and stock, respectively. Greatest chlorophyll contents were recorded (75.3 SPAD) in lisianthus, while (81.6 SPAD) in stock, when sprayed with Isabion and humic acid, respectively. Isabion consistently yielded best results indicating its potential as an effective biostimulant for promoting growth, yield, and quality attributes, and may be used by the growers to enhance yield and quality of selected specialty cut species.

  PublisherDOI

• Optimal production protocols for cut China aster (Callistephus chinensis L.) and snapdragon (Antirrhinum majus L.)

  Pakistan Journal of Botany · 2025-08-27

  article
  PublisherDOI

• Simulated spring freezes cause bud abortion and receptacle necrosis in <i>Paeonia lactiflora</i> ‘Festiva Maxima’

  Acta Horticulturae · 2025-07-01

  article
  PublisherDOI

• Long-term storage of cut flowers

  Acta Horticulturae · 2025-07-01

  article1st authorCorresponding
  PublisherDOI

• Optimal production protocols for cut Helianthus annuus L.

  Pakistan Journal of Botany · 2025-12-02

  article
  PublisherDOI

• Extended Storage of Cut Flowers Using Sub-zero Temperature

  HortTechnology · 2024-01-19 · 4 citations

  articleOpen accessSenior authorCorresponding

  The cut flower industry needs postharvest techniques that allow for extended storage of fresh cut flowers to meet consumer demands. We compared the use of a sub-zero storage temperature (−0.6 °C) to maintain viable flowers with improved or comparable vase life to flowers stored at the industry standard (4 °C). The vase life of 17 commercially important cut flower species, alstroemeria ( Alstroemeria ), anemone ( Anemone coronaria ), campanula ( Campanula medium ), carnation ( Dianthus caryophyllus ), chrysanthemum ( Chrysanthemum ), delphinium ( Delphinium elatum ), freesia ( Freesia ), gerbera ( Gerbera jamesonii ), gypsophila ( Gypsophila paniculata ), larkspur ( Consolida ), lily ( Lilium ), lisianthus ( Eustoma grandiflorum ), ranunculus ( Ranunculus asiaticus ), rose ( Rosa hybrida ), stock ( Matthiola incana ), sunflower ( Helianthus annuus ), and tuberose ( Polianthes tuberosa ), when stored dry at −0.6 °C for durations of 4, 8, and 12 weeks was comparable to or longer than that when stored at 4 °C. Tuberose stems were not viable after holding for any storage duration or temperature. Experiment 2 compared the use of a prestorage pulsing treatment of water, hydrating solution, or holding solution containing carbohydrates for 8 hours before extended storage for carnation, chrysanthemum, delphinium, lily, and rose stems. Stems of carnation benefitted from pulsing with a hydrating solution and maintained vase life similar to that of nonstored control stems when stored for 4 weeks at −0.6 °C. Conversely, rose stems only maintained vase life similar to that of nonstored control stems when held at 4 °C for all pulsing solutions. Lily and chrysanthemum stems had a decline in vase life with all pulsing solutions and only remained viable after 8 weeks of storage when held at −0.6 °C. Additionally, stored chrysanthemum and lily stems had a longer vase life when stored at −0.6 °C than that when held at 4 °C after 4 and 8 weeks of storage, respectively, with all pulsing solutions. Delphinium stems were not viable after any storage duration. Experiment 3 further evaluated carnation, lily, and rose stems with and without a prestorage acclimation period at 4 °C for either 24 hours or 1 week before extended storage of 4, 6, or 8 weeks. Holding stems at 4 °C for 1 week before extended storage reduced the vase life of all species. Rose stems remained viable after 8 weeks of extended storage when held at −0.6 °C, but only when no prestorage hold was used. Lily and rose stems were not viable beyond 4-week storage durations when held at 4 °C, but they remained viable with no prestorage holding period after 8 weeks at −0.6 °C. Carnation stems maintained a longer vase life irrespective of a prestorage holding period when stored at −0.6 °C. Through this analysis, we showed that many species of cut flowers may be held at a sub-zero temperature with vase life better than or comparable to that with the industry standard of 4 °C.

  PublisherOA PDFDOI

• Postharvest handling and vase life of cut sunflower

  Canadian Journal of Plant Science · 2023-02-24 · 1 citations

  articleOpen accessSenior authorCorresponding

  The sunflower ( Helianthus annuus L.) is a commercially important cut flower requiring research into postharvest factors such as recutting, water uptake, stem number, cooling rate, and storage temperature to maximize vase life. Stems of 'Sunbright' sunflowers were either recut before or after a drying period up to 48 h. Water uptake, stem quality, and microbial counts were determined 4 days after rehydration. Water potential was determined on five corresponding leaves per treatment. The effects of stem number per vase were evaluated with either 1, 3, 5, or 10 stems. Effects of cooling rate were determined by temperatures of 5 °C for 3 days in the dark, 5 °C for 2 days in the dark preceded by 24 h at either 20 °C with light or 32 °C in a shaded area outdoors, or were maintained in a shaded area at 32 °C for 3 days. Hydration and storage temperature effects were determined by either transferring to a postharvest environment, 20 °C cooler for 2 h, immediate storage for 2 days at 5 °C, or 3 days at 5 °C after recutting the basal stem. Allowing stems to dry up to 48 h reduced vase life by 2.3 days or less. Vase life was unaffected by harvesting into water or by the number of stems in a vase but was affected by temperature such that the longest vase life of 13.2 days occurred when stems were stored for 3 days at 5 ± 0.5 °C followed by postharvest evaluation at 20 ± 1 °C.

  PublisherOA PDFDOI

• Academic Prolfes of Students in a College of Agriculture

  NACTA Journal · 2023-08-11

  articleOpen access

  This paper establishes a clearer picture of the demographics of a single cohort of undergraduate students that entered [State’s] College of Agriculture and Life Sciences (CALS) in the fall semester of 2013. We compared the demographics of the cohort with the overall population of [State] to determine how well the student population at CALS represents the state it serves. We found that female students, White students, and students from economically developed counties were over-represented in the cohort as compared to the general population of the state. Using descriptive statistics, we created academic profiles for student groups of interest. The comparisons we made between groups show evidence that male, Latinx, out-of-state, and nontraditional students have mean graduation rates which are troublingly low. This research can help to guide efforts at these institutions to more effectively develop resources to continue to facilitate success for student groups who are thriving and to better support those who are experiencing hardship.

  PublisherOA PDFDOI

Frequent coauthors

• Iftikhar Ahmad

  41 shared

• James E. Faust

  Clemson University

  33 shared

• Brian E. Whipker

  North Carolina State University

  16 shared

• Janet C. Cole

  15 shared

• Ben A. Bergmann

  North Carolina State University

  14 shared

• Harold F. Wilkins

  14 shared

• Iftikhar Ahmad

  13 shared

• W. Roland Leatherwood

  North Carolina State University

  13 shared

Awards & honors

• Seed Your Future (founding member)
• Executive Advisor for the Association of Specialty Flower Gr…
• co-PI for the FFAR Fellows