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Open access

Richard H. Mattson and Richard E. Widmer

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

Richard H. Mattson and Richard E. Widmer

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

Richard H. Mattson and Richard E. Widmer

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.

Free access

Brian E. Corr and Richard E. Widmer

The influences of irradiance level, day length, temperature, and leaf area on growth and flowering of Zantedeschia elliottiana Engl. W. Wats (yellow calla lily) and Z. rehmannii (pink calla lily) were determined. Plants grown with 45% or 15% of natural irradiance were taller than those grown under full natural irradiance but flowered at the same time and produced a similar number of flowers. Leaf removal treatments had no effect on any characteristic measured. Plants grown with a night interruption (NI; 2200 hr to 0200 hr) were taller than those under short days (SD = 8 hours), but flowered at the same time and produced a similar number of flowers. Plants were grown with air at 15 or 20C in combination with medium temperatures at ambient level (1C less than air temperature) or a constant 20 or 25C. Z. rehmannii grown with the medium at 20 or 25C and air at 1.5 or 20C flowered faster and were taller than plants grown with air at 15C and with the medium at ambient temperature, but plants from all temperatures produced the same number of flowers over a 120-day cycle. When plants grown with a NI in the first cycle were replanted and grown through a second cycle, they were taller than plants grown from SD treatment first-cycle plants. No first growth-cycle treatment influenced flowering in the second growth cycle.

Free access

Brian E. Corr and Richard E. Widmer

Growth and flowering of Zantedeschia elliottiana W. Wats. and Z. rehmannii Engl. were studied. Rhizomes of both species were produced either in a glasshouse or outdoors in California. Plants grown from glasshouse-produced rhizomes flowered within 90 days only when a preplant rhizome soak of 500 ppm GA, was applied. Control plants of both species flowered when grown from field-produced rhizomes, but a GA3 preplant rhizome soak significantly increased the number of flowers (spathe and spadix) produced. Paclobutrazol, applied as a preplant rhizome soak or as a soil drench when shoots were 2 to 3 cm long, significantly limited plant height of Z. rehmannii from either source if not treated with GA,. Paclobutrazol and GA, treatments interacted significantly to affect height and number of flowers of Z. rehmannii grown from field-produced rhizomes. Treatment with GA3 overcame the dwarfing effect of paclobutrazol, while paclobutrazol treatment limited flower production. Z. rehmannii rhizomes >6.5 cm in diameter produced more shoots and leaves than smaller rhizomes, regardless of GA3 treatment. Emergence, number of shoots, and number of leaves from Z. elliottiana were not significantly affected by the rhizome size-GA3 variable combination. Production of normal flowers was increased by GA3 treatment of all sizes of Z. rehmannii rhizomes except the smallest, with the most flowers being produced by plants from the largest rhizomes. Production of deformed flowers was greatest from rhizomes treated with 500 ppm GA3, with no deformed flowers on control plants.

Open access

Brian E. Corr and Richard E. Widmer

Abstract

Zantedeschia elliottiana Engl. and Z. rehmannii W. Wats. rhizomes replanted immediately after leaf removal (without a period of storage) did not grow. Rhizomes replanted after leaf senescence, induced by withholding water, sprouted without an additional storage period, but height and number of leaves and shoots per rhizome were greater from rhizomes stored for ≥3 weeks. Rhizomes stored at 22°C for 6 weeks lost significantly more weight than rhizomes stored at 4° or 9°. Height and number of leaves and shoots per rhizome were greatest after 9° storage for both species, but differences were significant for Z. rehmannii only.

Open access

Brian E. Corr and Richard E. Widmer

Abstract

Gibberellic acid (GA3) was applied to Zantedeschia elliottiana (W. Wats.) and Z. rehmannii (Engl.) (yellow and pink calla lily) at 0, 50, 100, 500, or 1000 ppm, either as a preplant rhizome 10-min soak or as a foliar spray. Soaking rhizomes in 500 ppm GA3 prior to planting increased number of flowering shoots and flowers per shoot. Leaves on treated plants were narrower, but length was unaffected. Flower height was not affected. Foliar sprays did not alter any measured parameter. A preplant GA soak may be useful in the production of Zantedeschia as flowering potted plants. Chemical name used: (1α, 2β, 4aα, 4bβ, 10β)-2,4a,7-trihydroxy-1-methyl-8-methylenegibb-3-ene-1,10-dicarboxylic acid 1,4a-lactone (GA3).

Open access

Robert E. Lyons and Richard E. Widmer

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

Robert G. Anderson and Richard E. Widmer

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.

Free access

Neil O. Anderson, Peter D. Ascher, Richard E. Widmer, and James J. Luby

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.