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John M. Dole, Frankie L. Fanelli, William C. Fonteno, Beth Harden, and Sylvia M. Blankenship

Optimum postharvest handling procedures were determined for Linaria maroccana `Lace Violet', Trachelium`Jemmy Royal Purple', and Zinnia elegans `Benary's Giant Scarlet' and `Sungold.' A 24-hour 10% or 20% sucrose pulse increased the vase life of Linaria by 2–4 days, resulting in a vase life of 9 days as compared to 5 days for control flowers held in deionized (DI) water. Use of floral foam and cold storage at 1 °C for 1 week decreased vase life. Treatment with either 0.1 or 1.0 ppm ethylene had no effect. The use of a commercial holding solution (Floralife Professional or Chrysal Professional 2 Processing Solution) or 2% or 3% sucrose increased vase life 4–10 days. For cut Trachelium, ethylene caused florets to close entirely or stop opening; 1-MCP and STS prevented these ethylene effects. Stems tolerated 4 days of 1 °C storage, but 1 week or more of storage reduced the 14-day vase life of unstored flowers to 9 days. Stems in 2% or 4% sucrose had a longer vase life compared to DI water. While the use of floral foam was not detrimental when used with sucrose solutions, it reduced vase life when sucrose was not used. Zinnia stems could not be cold stored for 1 week at 1 °C due to loss of turgidity and cold damage. Stems stored dry at 5 °C regained turgidity and averaged a vase life of 14 days; however, petals remained slightly twisted and curled after being in the vase for several days. Treatment with ethylene had no effect. Floral foam reduced vase life to 9–10 days.

Open access

Erin M.R. Clark, John M. Dole, and Jennifer Kalinowski

Six experiments were conducted using three cultivars to investigate the impact of water electrical conductivity (EC) and the addition of nutrients to vase solutions on postharvest quality of cut rose (Rosa hybrids) stems. Postharvest quality of cut ‘Freedom’ rose stems was evaluated using solutions containing either distilled water with sodium chloride (DW+NaCl) or DW+NaCl with the addition of a commercial floral preservative (holding solution containing carbohydrates and biocide) to generate a range of EC values (Expts. 1 and 2). The third experiment compared the effect of different EC levels from the salts NaCl, sodium sulfate (Na2SO4), and calcium chloride (CaCl2). The fourth experiment investigated EC’s impact on rose stems with the addition of two rose cultivars (Charlotte and Classy). When ‘Freedom’ stems were subjected to DW+NaCl, the longest vase life was achieved with 0.5 dS·m–1. The addition of holding solution not only extended vase life but also counteracted the negative effects of high EC with maximum vase life occurring at 1.0 dS·m–1. Furthermore, stems in the holding solution experienced significantly less bent neck and the flowers opened more fully than those in DW. Stems placed in DW with a holding solution also experienced more petal bluing, pigment loss, necrotic edges, and wilting than those held in DW alone. This effect was likely due to increased vase life. Salt solutions containing Na2SO4 and CaCl2 resulted in extended vase life at 1.0 dS·m–1, but increasing salt levels decreased overall vase life. As EC increased, regardless of salt type, water uptake also increased up to a maximum at 0.5 or 1.0 dS·m–1 and then continually declined. Maximum vase life was observed at 1.5 dS·m–1 for cut ‘Charlotte’ stems, and at 1.0 dS·m–1 for ‘Classy’ with the addition of a holding solution. Physiological effects were different based on cultivar, as observed with Charlotte and Freedom flowers that opened further and had less petal browning than Classy flowers. ‘Freedom’ had the greatest pigment loss, but this effect decreased with increasing EC. Further correlational analysis showed that in water-only solutions, initial and final EC accounted for 44% and 41% of the variation in vase life data, respectively, whereas initial pH accounted for 24% of variation. However, the presence of carbohydrates and biocides from the holding solution was found to have a greater effect on overall vase life compared with water pH or EC. Finally, in Expts. 5 and 6, cut ‘Freedom’ stems were subjected to DW solutions containing 0.1, 1, 10, or 100 mg·L–1 boron, copper, iron, potassium, magnesium, manganese, or zinc. None of these solutions increased vase life. Conversely, 10 or 100 mg·L–1 boron and 100 mg·L–1 copper solutions reduced vase life. Finally, the addition of NaCl to a maximum of 0.83 dS·m–1 increased the vase life in all solutions. These analyses highlight the importance of water quality and its elemental constituents on the vase life of cut rose stems and that the use of a holding solution can overcome the negative effects of high EC water.

Free access

John M. Dole, Frankie L. Fanelli, William C. Fonteno, Beth Harden, and Sylvia M. Blankenship

Optimum postharvest handling procedures were determined for Dahlia `Karma Thalia', Lupinusmutabilis ssp. cruickshankii`Sunrise', Papaver nudicaule `Temptress', and Rudbeckia`Indian Summer.' Dahlia harvested fully open had a vase life of 7–10 days in deionized (DI) water that was increased by 1.5–2 days using commercial holding solutions (Chrysal Professional 2 Processing Solution or Floralife Professional). Neither floral foam nor 0.1–1.0 ppm ethylene had any effect on vase life. One week of cold storage at 1 °C reduced vase life up to 2 days. The longest vase life, 12–13 days, was obtained when floral buds, showing a minimum of 50% color, were harvested at the breaking stage (one petal open) and placed in 2% or 4% sucrose or a commercial holding solution. Lupinus flowers held in DI water lasted 8–12 days; 1 week cold storage at 1 °C reduced vase life by 3 days. Florets and buds abscised or failed to open when exposed to ethylene; STS pretreatment prevented the effects of ethylene. Commercial holding solutions increased Papaver vase life to 7–8 days from 5.5 days for stems held in DI water. While stems could be cold stored for 1 week at 1 °C with no decrease in vase life, 2 weeks of cold storage reduced vase life. Flowers were not affected by foam or ethylene. Rudbeckia had a vase life of 27–37 days and no treatments extended vase life. Stems could be stored at 2 °C for up to 2 weeks and were not ethylene sensitive. Floral foam reduced the vase life over 50%, but still resulted in a 13-day vase life.

Free access

Douglas C. Sanders, Dennis J. Osborne, Mary M. Peet, John M. Dole, and Julia L. Kornegay

Many potential students, because of distance from the university campus and/or job requirements, cannot take traditional courses on-campus. This group of learners is “place-bound”—a group of learners who may be employed full-time, most likely married with job responsibilities and/or other situations demanding most of their attention. The Horticultural Science Department and Graduate School at N.C. State University are addressing place-bound limitations in several ways, including the creation and offering of a Graduate Certificate Program in Horticultural Science via distance education (DE). By using DE, high demand, low-seat-available classes can offer additional enrollment for credit. Second, courses can be offered asynchronously or with alternative delivery methods. Also, courses offered collaboratively among institutions can generate a level of interest and enthusiasm that may not exist for “home-grown” courses. Such efforts as these promise to help meet continuing education demands of “non-traditional” students. These include Cooperative Extension's more than 120 Horticultural Crops Extension Agents (“field faculty”) and over 300 other field faculty whose interests include horticultural topics.

Full access

Brian A. Krug, Brian E. Whipker, Ingram McCall, and John M. Dole

Preplant bulb soaks of ancymidol, flurprimidol, paclobutrazol, and uniconazole; foliar sprays of flurprimidol; and substrate drenches of flurprimidol, paclobutrazol, and uniconazole were compared for height control of `Prominence' tulips (Tulipa sp.). Height control was evaluated at anthesis in the greenhouse and 10 days later under postharvest conditions. Substrate drenches of ancymidol, flurprimidol, and paclobutrazol resulted in adequate control using concentrations of 0.5, 0.5, and 1 mg/pot a.i. (28,350 mg = 1 oz), respectively. At these concentrations, ancymidol drenches cost $0.06/pot and paclobutrazol drenches $0.03/pot. Since flurprimidol is not yet available and no price is available, growers will need to assess the cost compared to ancymidol and paclobutrazol. Flurprimidol foliar sprays at <80 mg·L–1 (ppm) were ineffective in controlling height during greenhouse forcing, but during postharvest evaluation 80 mg·L–1 resulted in 14% shorter plants than the untreated control. Preplant bulb soaks of flurprimidol, paclobutrazol, and uniconazole at concentrations of 25, 50, and 10 mg·L–1, respectively, effectively controlled plant height. Preplant plant growth regulator soaks are a cost-effective method of controlling plant height of tulips because of the limited amount of chemical required to treat a large quantity of bulbs.

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Iftikhar Ahmad, Muhammad B. Rafiq, John M. Dole, Bilal Abdullah, and Kinza Habib

Favorable agro-climatic conditions and comparatively cheaper and readily available human resources offer a promising business opportunity to cut flower production in Pakistan. Presently, growers are limited to traditional cut flower crops such as rose (Rosa hybrids), gladiolus (Gladiolus hybrids), marigold (Tagetes erecta), and tuberose (Polianthes tuberosa) because of unavailability of improved new species and cultivars. To diversify cut flower production in Pakistan, a study was conducted to evaluate the production and postharvest performance of different cultivars of delphinium (Delphinium hybrids), snapdragon (Antirrhinum majus), and stock (Matthiola incana) in Faisalabad, Punjab, Pakistan. ‘Guardian White’ delphinium had the shortest time to harvest first marketable stems (160 days) with comparatively shorter stems (87.7 cm). Whereas ‘Aurora White’ and ‘Aurora Blue’ were high-temperature tolerant and produced attractive racemes with longer stems; 112.0 and 99.7 cm, respectively. All cultivars lasted about 7 days in distilled water (DW). ‘Cheerful White’ stock had the shortest cropping time and produced highest quality double flowers with longest stems (51.8 cm) compared with other cultivars tested. Vase solution of 4% sucrose supplemented with 100 mg·L−1 silver nitrate (AgNO3) extended the vase life of ‘Cheerful White’ stock up to 11.8 days compared with 8.2 days in DW. Pulsing with 10% sucrose supplemented with 100 mg·L−1 AgNO3 extended the longevity of ‘Lucinda Dark Rose Double’ stock (10.2 days) similar to vase solution of 4% sucrose plus 100 mg·L−1 AgNO3; however, ‘Lucinda Dark Rose Double’ stock produced shorter stems than ‘Cheerful White’. ‘Appleblossom’ snapdragon produced >10 marketable stems per plant with highest quality attractive flowers, and stout stems, which lasted 10.8 days in 4% sucrose vase solution supplemented with 100 mg·L−1 AgNO3. Among tested species/cultivars, all exotic species/cultivars produced uniform high quality stems resulting in higher productivity as compared with local cultivars and were favorably appraised by flower growers/retailers and are best suited for diversification of local cut flower industry.

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Brian A. Krug, Brian E. Whipker, Ingram McCall, and John M. Dole

Three experiments were conducted to determine the effectiveness of plant growth regulators (PGRs) on `Tete a Tete', `Dutch Master', and `Sweetness' narcissus (Narcissus pseudonarcissus). Ethephon foliar sprays (500 to 2500 mg·L-1) and substrate drenches of flurprimidol and paclobutrazol (0.25 to 4 mg/pot a.i.) did not control height during greenhouse forcing of `Tete a Tete' at any concentration trialed. Stem stretch was controlled during postharvest evaluation with ethephon foliar sprays ≥1000 mg·L-1, flurprimidol substrate drenches ≥0.5 mg/pot a.i., and paclobutrazol substrate drenches of 4 mg/pot a.i. A second experiment investigated preplant bulb soaks of flurprimidol (10 to 40 mg·L-1) applied to `Dutch Master' and `Tete a Tete' narcissus bulbs. Flurprimidol preplant bulb soaks controlled postharvest stretch on `Tete a Tete' and `Dutch Master' at concentrations ≥15 and ≥10 mg·L-1, respectively. A third experiment was conducted with paclobutrazol (75 to 375 mg·L-1) on `Tete a Tete' and `Dutch Master' and three concentrations of flurprimidol on `Sweetness' to determine optimal soak recommendations. Paclobutrazol preplant bulb soaks ≥75 mg·L-1 controlled postharvest stretch of `Tete a Tete' and `Dutch Master', while 37.5 mg·L-1 of flurprimidol controlled postharvest stretch of `Sweetness'. Based on the results of these experiments, growers can now select a PGR to help control excessive plant growth.

Open access

Cristian E. Loyola, John M. Dole, and Rebecca Dunning

Imports of cut flowers into the United States have doubled in the last 20 years and come mainly from Colombia and Ecuador. We surveyed the cut flower industry in South and Central America, focusing on Colombia and Ecuador, to determine their production and postharvest problems. We received a total of 51 responses, of which 62% of the respondents had 100 or more employees. The most commonly grown or handled crops were rose (Rosa hybrids), carnation (Dianthus caryophyllus), chrysanthemum (Chrysanthemum ×grandiflorum), alstroemeria (Alstroemeria cultivars), gerbera (Gerbera jamesonii), and hydrangea (Hydrangea species), in order of ranking. The most significant production problem was insect management, with disease management and crop timing the next most important issues. The most important species-specific issues in production were phytosanitary problems, disease (causal organism not specified), leaf miner (Lepidoptera, Symphyta, or Diptera), and thrips (Thysanoptera). The main overall postharvest problem was temperature management, followed by hydration and flower food management and botrytis (Botrytis cinerea). In regard to on-farm postharvest handling, damage to the flowers was the most mentioned issue. For the postharvest during storage and transport phase, temperature management, air transport, damage, and botrytis were the most important problems. The most mentioned customer complaints were damage, botrytis, and phytosanitary problems. The results of this survey can be used by researchers to focus their work on topics of most need. Improved production and postharvest handling will support the continued growth of the cut flower industry.

Full access

Brian A. Krug, Brian E. Whipker, Ingram McCall, and John M. Dole

Preplant bulb soaks of flurprimidol, paclobutrazol, and uniconazole; foliar sprays of ethephon and flurprimidol; and substrate drenches of flurprimidol were compared for height control of `Anna Marie' hyacinths (Hyacinthus orientalis). Preplant bulb soak concentrations of flurprimidol and paclobutrazol were from 25 to 400 mg·L-1, and uniconazole from 5 to 80 mg·L-1. Height control was evaluated at anthesis and 11 days later under postharvest conditions. Ethephon (250 to 2000 mg·L-1) and flurprimidol (5 to 80 mg·L-1) foliar sprays were ineffective. Flurprimidol (0.25 to 4 mg/pot) drenches had no effect during forcing, but controlled postharvest height at concentrations ≥0.25 mg/pot a.i. with at least 4% shorter plants than the untreated control. Preplant bulb soaks resulted in height control with flurprimidol ≥25 mg·L-1, paclobutrazol ≥100 mg·L-1, and uniconazole ≥40 mg·L-1; having at least 9%, 6%, and 19%, respectively, shorter plants than the untreated control. Based on our results, flurprimidol preplant bulb soaks have a greater efficacy than either uniconazole or paclobutrazol. Preplant PGR soaks are a cost-effective method of controlling plant height of hyacinths because of the limited amount of chemical required to treat a large quantity of bulbs.

Free access

W. Roland Leatherwood, John M. Dole, Ben A. Bergmann, and James E. Faust

Knowing which herbaceous taxa are ethylene sensitive and managing exposure of unrooted terminal stem cuttings to ethylene in those taxa are critical for maintaining high-quality propagules that root readily. Of 59 taxa surveyed, freshly harvested terminal cuttings of Begonia hybrid ‘Snowcap’, Lantana camara L. ‘Patriot Sunbeam’, and Portulaca oleracea L. ‘Fairytales Sleeping Beauty’ were sensitive to exogenous application of 1 μL·L−1 ethylene, as demonstrated by leaf abscission within 24 hours of treatment. Exposure to 1-methylcyclopropene (1-MCP) at 700 μL·L−1 for 4 hours before ethylene treatment prevented ethylene injury in these species/cultivars. Exposing unrooted cuttings to 700 μL·L−1 1-MCP induced significant endogenous ethylene biosynthesis in terminal cuttings of the five taxa tested: Euphorbia pulcherrima Willd. ex Klotzsch ‘Visions of Grandeur’, Impatiens hawkeri W. Bull ‘Sonic Red’, Pelargonium peltatum (L.) L’Hérit. ‘Mandarin’, Pelargonium ×hortorum Bailey (pro sp.) [inquinans × zonale] ‘Rocky Mountain White’, and Petunia ×hybrida Vilm. ‘Suncatcher Coral Prism’. Exogenous 1 μL·L−1 ethylene improved adventitious rooting in two cultivars: Begonia hybrid Anita Louise and Fuchsia triphylla L. Honeysuckle. Other trials showed that 1-MCP exposure reduced root number and length of P. ×hortorum ‘Kardino’ and delayed adventitious rooting in all six cultivars tested: Angelonia angustifolia Benth. ‘Carita Lavender’, Calibrachoa ×hybrida Llave & Lex. ‘Terra Cotta’, I. hawkeri ‘Sonic Red’, P. oleracea ‘Fairytales Sleeping Beauty’, Sutera cordata Kuntze ‘Abunda Blue Improved’, and Verbena ×hybrida Groenl. & Ruempl. ‘Aztec Wild Rose’. Subsequent exposure to 1 μL·L−1 ethylene partially mitigated the negative effects on rooting from exposing cuttings to 1-MCP.