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Theresa Bosma and John M. Dole

Various postharvest treatments were evaluated for effect on longevity and quality of cut Campanula medium L. `Champion Blue' and `Champion Pink' stems. Stems stored at 2 °C either wet or dry had no difference in vase life or percent flowers opened; however, flowers stored dry had a slightly greater percentage of senesced flowers at termination. Increasing storage duration from 1 to 3 weeks decreased vase life. Stems pretreated for 4 hours with 38 °C floral solution (deionized water amended to pH 3.5 with citric acid and 200 mg·L-1 8-HQC) or a 1-MCP pulse followed by a 5% sucrose pulse solution produced the longest vase life (10.3 or 10.4 days, respectively). Flowers opening after treatments commenced were paler than those flowers already opened and a 24-hour pretreatment with 5% or 10% sucrose did not prevent this color reduction. Stems had an average vase life of only 3.3 days when placed in floral vase foam but lasted 10.0 days without foam. Optimum sucrose concentration was 1.0% to 2.0% for stems placed in 22 °C floral vase solution without foam and 4% for stems placed in foam. High (110 μmol·m-2·s-1) or low (10 μmol·m-2·s-1) light levels did not affect postharvest parameters, but the most recently opened flowers were paler under low light conditions than under high light conditions. Chemical names used: 8-hydroxyquinoline citrate (8-HQC); 1-methylcyclopropene (1-MCP).

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Theresa Bosma, John Dole, and Niels Maness

Marigold flower pigments can be extracted and used as a natural source of food colorants in the poultry and dairy industry. These pigments impart an orange color to egg yolks and a yellowish color to dairy products. We examined four African marigold cultivars for their ability to be commercially grown and harvested mechanically. `E-1236' yielded the highest quantity of lutein (22 kg/ha), a carotenoid pigment, using a spectrophotometer for quantification. `E-1236' and `A-975' were the earliest flowering cultivars, 11 June 1998 for transplants and 9 July 1998 for direct-seeded, at 8 weeks after sowing regardless of field establishment method. `E-1236' produced the greatest number of flowers in a production season, both as transplants (68 flowers/plant) and direct-seeded (57 flowers/plant) at 363,290 plants/ha. Transplants resulted in two more harvests in a single season than direct-seeded plants. Subsequently, more flowers and petal material were produced for pigment extraction than with direct-seeded plants. A one-time application of ammonium nitrate (28.02 kg/ha) at mid-season did not significantly effect flower number, flower weight, or pigment yield. Experiment was repeated in 1999 with four cultivars, two field establishment methods, seven harvest dates, and five nitrogen applications.

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Kenneth E. Conway, John M. Dole, Theresa L. Bosma, and Niels O. Maness

Field seedling emergence of four african marigold (Tagetes erecta) breeding lines, A-975, E-1236, I-822, and `Orange Lady', was examined using three or four spring sowing dates and either osmotic or solid matrix priming. Delayed sowing decreased emergence time. Sowing from middle to late April [average soil temperatures 77.0 to 84.2 °F (25 to 29 °C)] resulted in the highest total emergence percentages. Greater fl ower quantities [4.9 to 5.1 million/acre (12.11 to 12.60 million/ha)] and estimated yield [7.5 to 10.8 tons/acre (16.81 to 24.20 t·ha-1)] indicate mid to late April is the optimum time period for direct sowing unprimed seed in the southern Great Plains. Differences between lines were evident in emergence parameters and fl ower harvest data for each year examined, but results were inconsistent from year to year. However, A-975 and E-1236 produced harvestable fl owers most quickly, about 15 d before I-822, which could result in an additional harvest during a season. Osmotic priming of E-1236 and I-822 seed shortened emergence time, increased emergence uniformity, and increased total emergence percentage at early sowing dates as compared to both solid matrix primed and unprimed seed.

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Theresa L. Bosma, Janet C. Cole, Kenneth E. Conway, and John M. Dole

Canterbury bells (Campanula medium `Champion Blue') seeds were primed using calcined clay at 68 °F (20 °C) for 1, 3, or 5 days at water potentials (Ψ) of -25, -20, -18, or -16 bars (-2.5, -2.0, -1.8, or -1.6 MPa). Germination was fastest (3.0 to 3.1 days) after priming with a Ψ of -18 or -16 bars for 5 days. Seeds primed for 3 or 5 days with moisture present germinated faster than nonprimed seeds, but time to 50% germination (T50) was longer when seeds were primed for 1 day regardless of Ψ compared to nonprimed seed. Germination uniformity decreased (time from 10% to 90% germination, T10-90, increased) as Ψ increased. Although a curvilinear relationship existed between T10-90 and priming duration, T10-90 did not differ between nonprimed seeds and seeds in any priming treatment except those primed for 3 days with 20% moisture (-16 bars). Priming did not affect total germination percentage (97%).