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Carlma B. Bratcher, John M. Dole, and Janet C. Cole

The effect of cold on germination rate, percentage and range of five cut flowers was investigated: Baptisia australis (Wild Blue Indigo), Echinacea purpurea (Purple Coneflower), Helianthus maximilianii (Maximillian Sunflower), Solidago petiolaris (Spike Goldenrod), and Vernonia missurica (lronweed). Viability was determined for the species using TTC staining and germination based on percent viable seed. Seeds were given 0, 2, 4, 6, 8, or 10 weeks of cold at 5°C. Increasing weeks of cold decreased days to germination in all five species, with Baptisia demonstrating the greatest effect. The germination percent increased as weeks of cold increased in all five species, but was most significant in Helianthus and Vernonia. Days from first to last germinating seed was significantly decreased in all five species as weeks of cold increased. Four weeks of cold was optimum for Echinacea and Vernonia, while optimum weeks of cold for Helianthus and Solidago was six weeks and Baptisia ten weeks.

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Erin P. Moody, John M. Dole, and Jared Barnes

Various postharvest procedures were conducted on several rose (Rosa hybrida) cultivars to determine the effects on vase life, water uptake, change in fresh weight, stage of opening, and vase life termination criteria. Vase life was influenced by cultivar and vase solution. Commercial preservative solutions resulted in a longer vase life, smaller decrease in fresh weight than the controls, and smaller increase in water uptake. Vase life of nine cultivars in distilled water ranged from a low of 7.1 days for Queen 2000 to a high of 15.3 days for Forever Young. Flower termination criteria were also cultivar specific with Black Baccara, Classy, and Charlotte most prone to bent neck and blackening of petal tips. Exogenous ethylene at 0.4 or 4.0 μL·L−1 did not affect vase life but lowered water uptake. Application of the antiethylene agent silver thiosulfate (STS) at 0.2 mm concentration significantly improved vase life in five out of the nine cultivars (Anna, Charlotte, First Red, Freedom, and Konfetti) tested, but 1-methylcyclopropene (1-MCP) at 740 nL·L−1 did not improve vase life over the control. Both vase life and water uptake were reduced when more than one stem was placed in a vase; placing 10 stems in a vase shortened vase life by 1.4 days and impeded water uptake by up to 10.6 mL/stem per day. Increasing the amount of time stems remained dry before placing in a vase reduced vase life, but recutting immediately before placing in a vase minimized the decline. Increasing the amount of stem cut off the base up to 10 cm increased vase life.

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D. Steve Owens, Michael A. Schnelle, and John M. Dole

Rock garden plants, typically alpine in nature, are indigenous to higher elevations and thus perform poorly in the South. Consequently, they are not adapted to environments with tight clay soils, extreme heat, high humidity, and periodic drought. A video and extension circular were produced to demonstrate the construction, planting and maintenance of an appealing yet durable rock garden for Oklahoma. Modifications in soil type, plant materials, and arrangement of rock, wherein small micro-habitats are created, comprise the core of the project. The aforementioned educational materials benefit the gardening public with previously unavailable information for Oklahoma. The video is included in the Oklahoma State Univ. Cooperative Extension Service video library, where it is available via rental or purchase. It provides informative visual instruction, complementing the written publication that outlines stepwise construction techniques coupled with a list of adaptable plants. Both the publication and video may have applications for gardeners in peripheral states.

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Michael D. Frost, Janet C. Cole, and John M. Dole

Improving the quality of water released from containerized production nurseries and greenhouse operations is an increasing concern in many areas of the United States. The potential pollution threat to our ground and potable water reservoirs via the horticultural industry needs to receive attention from growers and researchers alike. `Orbit Red' geraniums were grown in 3:1 peat:perlite medium with microtube irrigation to study the effect of fertilizer source on geranium growth, micronutrient leaching, and nutrient distribution. Manufacturer's recommended rates of controlled-release (CRF) and water-soluble fertilizers (WSF) were used to fulfill the micronutrient requirement of the plants. Minimal differences in all growth parameters measured between WSF and CRF were determined. A greater percentage of Fe was leached from the WSF than CRF. In contrast, CRF had a greater percentage of Mn leached from the system than WRF during the experiment. Also, regardless of treatment, the upper and middle regions of the growing medium had a higher nutrient concentration than the lower region of medium.

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John M. Dole, Janet C. Cole, and Sharon L. von Broembsen

`Gutbier V-14 Glory' poinsettias (Euphorbia pulcherrima Willd. Ex. Klotzsch) grown with ebb-and-flow irrigation used the least amount of water and produced the least runoff, and plants grown with capillary mats used the greatest amount of water and produced the most runoff, compared to microtube and hand-watering systems. The maximum amount of water retained by the pots and media was greatest for the microtube and ebb-and-flow systems and became progressively lower for the hand-watering and capillary mat systems. The media and leachate electrical conductivity from plants grown with subirrigation systems was higher than those grown with top irrigation. For the two top-irrigation systems (microtube and hand-watering), plants grown with 250 mg N/liter from a 20N-4.4P-16.6K water-soluble fertilizer had greater leaf, stem, and total dry weights than those grown with 175 mg N/liter. The two subirrigation systems (ebb-and-flow and capillary mat) produced plants that were taller and had greater leaf, stem, and total dry weights when grown with 175 than with 250 mg N/liter. The higher fertilizer concentration led to increased N, P, Fe, and Mn concentration in the foliage. Nitrogen concentration was higher in top-irrigated plants than in subirrigated plants. The ebb-and-flow system produced the greatest total dry weight per liter of water applied and per liter of runoff; capillary mat watering was the least efficient in regard to water applied and runoff.

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Janet C. Cole, John M. Dole, and Vicki L. Stamback

Water quality has become a significant issue in the nursery industry. Local testing of runoff contamination from nursery production is, however, of little value to other growers because of the variation in management practices and nursery layouts. Two nursery blocks have been designed and constructed to test runoff from production with sprinkler and drip irrigation systems in combination with constant liquid fertilization and controlled release fertilizers. Management practices using various combinations of irrigation systems with fertilizer application rates are being tested in a small area with reasonable control of inputs. Preliminary data has shown no difference in plant response to irrigation method, but runoff was significantly reduced with drip irrigation. Plant quality was better with controlled release fertilizer, which generally yielded less N and P contamination in runoff, than constant liquid fertilization except during extremely hot weather.

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Bridget K. Behe, Paul B. Redman, and John M. Dole

Consumer flower-color preferences are of interest to market researchers, plant producers, and retailers because this information can help them to anticipate accurately the sales product mix. Our objective was to determine consumer bract-color preferences for 47 poinsettia (Euphorbia pulcherrima Willd. ex Klotzsch) cultivars. Visitors (124) to the Franklin Park Conservatory in Columbus, Ohio, rated `Sonora', a red cultivar, highest (4.6 of 5.0) of any cultivar. Nine of ten highest rated cultivars were red. We compared the ratings of poinsettia buyers with those of nonpoinsettia buyers and found only one difference: nonpoinsettia buyers rated `Jingle Bells III', a marble cultivar, higher (4.3) than poinsettia buyers (3.8). We also compared consumers who had purchased a red poinsettia to those who had purchased nonred colors and found that red poinsettia buyers rated `Sonora' higher (4.9) than nonred poinsettia buyers (4.5). Men rated `Red Elegance' higher (3.7) than women (3.3), whereas women rated `Freedom White' higher (3.1) than men (2.4). We found few differences between men and women, buyers and nonbuyers, and nonred buyers and red buyers, which may indicate a relatively homogeneous market that does not greatly differentiate among poinsettia bract color.

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Iftikhar Ahmad, John M. Dole, and Frank A. Blazich

Effects of harvest time (morning, noon, or afternoon) on water uptake, fresh weight changes, termination symptoms, leaf relative water content (LRWC), carbohydrate status, and vase life of cut ‘ABC Purple’ lisianthus (Eustoma grandiflorum Salisb.), ‘Double Eagle’ African Gold Coin Series marigold (Tagetes erecta L.), and ‘Deep Red’ Benary’s Giant Series zinnia (Zinnia elegans Jacq.) were studied. For stems of lisianthus harvested and then stored in the dark with the basal ends in water for 2 weeks at 3 ± 1 °C, those harvested at noon (1200 hr to 1300 hr) or in the afternoon (1700 hr to 1800 hr) had longer vase life compared with stems harvested in the morning (0700 hr to 0800 hr). However, stems of lisianthus evaluated without storage had no differences in vase life. Stems of marigold harvested in the afternoon had longer vase life than morning- or noon-harvested stems. Time of harvest had no effect on cut flower longevity of zinnia. However, vase life was considerably shorter for stems of all species when tested after 2 weeks storage compared with freshly harvested stems. Stems of zinnia harvested at noon had lower LRWC than morning- or afternoon-harvested stems. Marigold stems harvested in the afternoon and evaluated without storage had lowest LRWC on Day 7 of vase life. Harvest time or storage did not influence LRWC of lisianthus. Stems of marigold and lisianthus harvested at noon or in the afternoon had higher levels of carbohydrates compared with morning-harvested stems, whereas freshly harvested stems had higher concentrations of glucose and sucrose, which decreased during storage or the vase period. Sucrose concentrations varied more significantly among various tissues than other sugars presumably as a result of translocation during vase life. In summary, carbohydrate status of stems harvested at different times of the day varied greatly and affected postharvest longevity of cut marigold and lisianthus, but not zinnia.

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Nathan J. Jahnke, John M. Dole, and H. David Shew

Postharvest environments during storage and shipping are often conducive to plant stress and disease development. Liners of four cultivars of geraniums (Pelargonium ×hortorum) were evaluated every 2 days for their susceptibility to gray mold (Botrytis cinerea) and leaf yellowing over an 8-day simulated shipping period at either constant air temperature of 15 °C or variable air temperatures cycling every 24 hours between 10 and 30 °C. The latter treatment was created using air temperature logs of commercial liner shipments sent to five locations during Spring 2016 and Fall 2016. We sprayed a spore suspension of 2 × 104 or 2 × 106 to inoculate liners before they were subjected to the two temperature treatments. Disease ratings did not reach significant levels for the dry control until day 6 of storage. Regardless of the spore concentration, ratings were similar for inoculated cuttings. Independent of the storage temperature and spore concentration, liners developed minor lesions by day 2 of storage. Cultivars varied slightly in disease ratings, with Tango Dark Red being the most susceptible, followed by Patriot Bright Red, Patriot Rose Pink, and Americana Red. During the 8-day incubation period, ‘Patriot Rose Pink’ developed the most leaf yellowing compared with the other three cultivars. Liners that experienced variable air temperatures had marginal leaf yellowing by day 2, and this yellowing increased throughout the experiment. Liners placed at 15 °C had ≈50% less leaf yellowing compared with liners exposed to variable air temperatures until day 8, when leaf yellowing was similar between the two air temperature treatments. Disease caused by B. cinerea was avoided when simulated shipping was 2 days or fewer, and a stable air temperature of 15 °C reduced leaf yellowing on geranium liners compared with variable air temperatures.

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Jaime K. Morvant, John M. Dole, and Janet C. Cole

Pelargonium ×hortorum Bailey `Pinto Red' plants were fertilized with equal amounts of N, P, and K derived from: 1) 100% constant liquid fertilization (CLF); 2) 50% CLF plus 50% controlled-release fertilizer (CRF); or 3) 100% CRF per pot and irrigated using hand (HD), microtube (MT), ebb-and-flow (EF), or capillary mat (CM) irrigation systems. The treatment receiving 100% CRF produced greater total dry weights, and released lower concentrations of NO3-N, NH4-N, and PO4-P in the run-off than the 100% CLF treatment. The percentage of N lost as run-off was greatly reduced with the use of CRF. MT irrigation produced the greatest plant growth and HD irrigation produced the least. The EF system was the most water efficient, with only 4.7% of water lost as run-off. Combining the water-efficient EF system with the nutrient-efficient CRF produced the greatest percentage of N retained by plants and medium (90.7) and the lowest percentage of N lost in the run-off (1.7).