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  • Author or Editor: Richard E. Widmer x
  • Journal of the American Society for Horticultural Science x
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Abstract

Cut flower yield of four greenhouse rose cultivars was primarily influenced by solar radiation, while atmospheric CO2, air temperature, and soil nutrient levels were of lesser importance. Cultivars responded differently to atmospheric CO2 level and soil fertilization method. Roses fertilized with 20-20-20 in solution produced equivalent or greater flower yields than roses fertilized with 10-10-10 in dry form. Roses grown in CO2 enriched atmospheres did not require additional soil fertilization.

Regression coefficients and yield prediction equations were determined using nine environmental parameters. Monthly yield predictions were generally reliable, but cropping cycles and cultural practices decreased accuracy.

Open Access

Abstract

Four Rosa hybrida cultivars were grown in 100 to 500, 700 to 1300, and 1500 to 2500 ppm CO2 atmospheres for at least half the daylight hours from November to May. Production was studied continually for 24 months.

Numbers of flowering stems and lateral buds, fresh weight, and stem length were greater in CO2 supplemented atmospheres on hybrid tea and floribunda roses. Non-flowering percentages were lower for floribundas in CO2 enriched atmospheres. Greater leaf abscission and less root development were noted for hybrid tea and floribunda roses in 1500 to 2500 ppm CO2. Higher yields in non-CO2 supplementation periods (May to October) largely reflected growing conditions rather than CO2 effects.

Open Access

Abstract

Vase life and floral characteristics were studied for Rosa hybrida (cvs. Forever Yours, Briarcliff Supreme, Red Garnette, and Rose Elf) flowers grown in atmospheres containing 300 ± 200, 1000 ± 300, and 2000 ± 500 ppm CO2 for at least half of the daylight hours. Only ‘Red Garnette’ flowers grown in CO2-supplemented air had significantly longer vase life (one-half day) than those produced in normal atmospheres.

Open Access

Abstract

Treatments with gibberellic acid (GA3), naphthaleneacetic acid (NAA), or their combination to Cyclamen persicum Mill. ‘Swan Lake’ plants resulted in separate, antagonistic, or cooperative effects on leaf lamina unfolding, days to flowering, number of leaves at first flower, and length of the first flower's peduncle. Generally, GA3 accelerated plant growth nonspeciflcally, resulting in plants which flowered earlier than untreated plants, but with a similar number of leaves at first bud flowering. The combination of GA3 plus NAA specifically accelerated flowering, but this effect diminished as the treatment frequency or quantity of the NAA application increased.

Open Access

Abstract

Slow and inconsistent germination of cyclamen, Cyclamen persicum Mill., seed appeared to be more related to seed and seedling vigor than to any type of seed dormancy. Pregermination and germination seed treatments such as immersion in hot water, still and flowing water, cool moist storage, alternating temperatures and fungicide treatments were of little value. Treatment with gibberellin (GA) solutions accelerated germination but created an expelled embryo problem. The grower is advised to surface disinfest fully imbibed seed in 5% sodium hypochlorite for 20 sec to 1 min.

Open Access

The generation time (0.75 to 1.5 years) in perennial, hexaploid chrysanthemums [Dendranthema grandiflora Tzvelv. (Chrysanthemum morifolium Ramat.)] impedes the rate of progress for sexual breeding programs in creating new clonal cultivars, inbred lines for hybrid seed production, and genetic studies. Modifications to the crossing environment and embryo rescue were evaluated to minimize the chrysanthemum generation cycle. One greenhouse chrysanthemum clone was outcross-pollinated using a bulk pollen source. Following emasculation, inflorescences were either left in situ or the peduncle bases were placed in styrofoam boards floating on a solution of 1% sucrose and 200 ppm 8-HQC under laboratory conditions. Embryogenesis occurred at a faster rate under laboratory conditions as tested with histological techniques; the heart stage appeared as early as the second day after pollination, compared with 11 days using in situ methods. Total embryogenic development time ranged from 25 (laboratory seed development) to 52+ days (in situ ripening). In a second test, embryo rescue (ER) significantly improved percent seed set, percent germination, and percent of progeny reaching anthesis relative to normal development. ER progeny from both garden parents were significantly earlier in total generation time than corresponding non-ER siblings. Laboratory seed development and ER were then used sequentially to obtain an average progeny generation time of =100 days, thus allowing for three generations per year. The potential impact of these two techniques on breeding chrysanthemums and other perennial crops with long generation times is discussed.

Free access