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Poinsettia `Eckespoint Freedom' (Euphorbia pulcherrima), grown as single pinched plants in containers in a shade house (30% light exclusion) during 1992 and 1993, were provided interrupted night lighting from 2200 to 0200 hr. to determine the effect of extended lighting on vegetative and reproductive development. Plants were moved to short days at 2 day intervals from 14 Sept to 26 Oct 92 and from 26 Sept to 26 Oct 93 and were compared to plants grown with ambient daylengths. Dates of first bract in full color for ambient-day plants were 31 Oct 92 and 04 Nov 93. Marketable dates (5 bracts in color) for ambient-day plants were 21 Nov 92 and 18 Nov 93. Bract development was delayed in direct proportion to lighting beyond 02 Oct 92 and 04 Oct 93. Number of vegetative nodes increased from 7.4 to 12.8 and from 6.3 to 12.0 when ambient-day plants were compared to plants lit to 26 Oct of 1992 and 1993, respectively. Lateral stem caliper, measured 2 cm above the axil, was significantly greater on plants lit beyond 10 Oct. Plant stature was more upright when lit beyond 16 Oct, which was 30 days from pinching.
Abstract
Mature fruit and viable seed were produced from gladiolus spikes which were harvested in tight bud, placed in vases containing water, and hand pollinated. The addition of 600 ppm 8-hydroxyquinoline citrate + 2% sucrose (8-HQC + S) greatly increased fruit size, wt and the no. of viable seed. Nutrient solution decreased fruit and seed wt as compared to water alone and reduced the effect of 8-HQC + S.
Abstract
Leaf area required for development of flowering-size corms following simulated mowing of gladiolus spikes was determined and mowing height was compared to leaf area retained. Plants were sheared from 12 to 40 cm above the top of the beds in 4 cm increments. Shearing plants 12, 24, or 36 cm above the soil level left 5, 18, and 38% of the leaf area, respectively, compared to intact plants. Mowing at these heights reduced corm weight 76, 65, and 39%, total cormel weight 92, 62, and 22%, and number of corms ≥3.8 cm in diameter 96, 76, and 33%, respectively. Minimum shearing height for development of usable daughter corms for subsequent flower production was 28 cm.
Abstract
Various rates, types, and formulations of controlled-release fertilizers were evaluated as potential components in a trickle irrigation production system for spray chrysanthemums (Chrysanthemum morifolium Ramat.). Optimum rates of total-N, with 34 kg N/ha as soluble 6-2.6-5 (N-P-K) and the remainder as 14-6.1-11.6 Osmocote, were estimated to be from 489-501 kg per planted hectare in 2 tests. Other formulations or ratios of Osmocote and urea formaldehyde fertilizers at similar rates did not improve production or were not comparable to Osmocote 14-6.1-11.6 or to the commercial practice of weekly overhead liquid fertilization. A water savings of 70-80% was estimated with the controlled-release fertilizer-trickle irrigation system compared to overhead irrigation, while yields (marketable stems and height) were similar to those produced with overhead-liquid fertilization practices.
Abstract
Meiotic behavior was examined in 33 interspecific hybrids derived from 6 sections of the genus Dendrobium Swartz. The mean number of bivalents per pollen mother cell (PMC) of intrasectional Ceratobium hybrids was 18.9 as compared to 17.5 for Phalaenanthe × Ceratobium offspring. Mean bivalents of the intersectional hybrids of Ceratobium × Eleutheroglossum, Latourea × Ceratobium, Latourea × Phalaenanthe, Phalaenanthe × Eleutheroglossum, Phalaenanthe × Eugenanthe, and Phalaenanthe × Nigrohirsutae were 14.5, 9.0, 9.6, 11.8, 6.0, and 6.4, respectively. Percent of microspore tetrads formed reflected the chromosome homology of the parental species. Cytological observations indicated that species of the Ceratobium and Phalaenanthe sections are closely related, Eleutheroglossum is more closely related to Ceratobium than Phalaenanthe, and Latourea is equally related to Ceratobium and Phalaenanthe.
Abstract
Stored ‘Candidum,’ ‘Carolyn Whorton,’ and ‘Frieda Hemple’ caladium tubers were soaked for 0, 4, 8, 16, 32, or 64 hours in 0, 250, 500, or 1000 mg/liter gibberellic acid (GA3) solutions to determine if flowering could be enhanced during the subsequent forcing period. Mean number of inflorescences produced per plant with no soaking was 0.2, 0.7, and 0.0 for ‘Frieda Hemple,’ ‘Candidum,’ and ‘Carolyn Whorton’ respectively, while tubers soaked in 250 mg/liter GA3 for 16 hours at 23°C averaged 2.4, 3.7, and 4.0 inflorescences per plant, respectively. There was no significant difference in number of inflorescences per plant from tubers treated with 250, 500, and 1000 mg/liter GA3. Optimum soaking time was 8 hours for ‘Frieda Hemple’ and ‘Carolyn Whorton,’ and 16 hours for ‘Candidum.’
Gladiolus (G. grandiflorus) seed germination was light-independent, but temperature influenced the germination rate. Constant 20C promoted higher total germination (97%), fewer days (4.3) to 50% of final germination, and shorter span of days (4.8) between 10% and 90% germination than other constant temperatures, although similar results were achieved by alternating 12-h cycles of 20 to 25C. Total germination was unchanged after seed treatment for 7 days at 10 to -20C, but longer germination periods were required after treatments below -10C. Reducing seed moisture contents from 11.8% to 4.2% caused no reduction in total germination, but moisture contents below 6.6% delayed achieving 50% of final germination and extended the periods from 10% to 90% of germination. Temperature and relative humidity (RH) during storage were important in retaining seed viability, with RH having a larger effect. Smallest declines in total germination during 12 months of storage occurred at 11% and 33% RH at 15C. The statistical analysis estimated the optimum seed storage at 14C and 26% RH.
Abstract
Single applications of 500 ppm GA3 on ‘Iceberg’ and ‘Midnight Blue’ statice made at 87, 101 and 115 days after seeding reduced mean flowering time 90, 72, and 45 days, respectively, compared to unsprayed plants. Applications made 129 days after seeding had no significant effect on flowering. Repeated sprays were not beneficial and, in some cases, delayed flowering as compared to single applications.
Abstract
Costs for growing 10 cm and 15 cm potted chrysanthemums (Chrysanthemum morifolium Ramet.) under shade cloth on capillary mats in Florida were estimated to be $0.42 and $1.52 per plant, respectively. If 10 cm and 15 cm potted chrysanthemums wholesale at $0.60 and $2.00 per plant, respectively, annual return above growing costs from a 2 ha structure would be $37, 514 and $13, 667 for 10 cm and 15 cm plants, respectively. Growers would need to wholesale 15 cm pot chrysanthemums at about $2.25 to equal annual return from 10 cm plants.