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Abstract

Recent interest in the production of Rhododendrons as potted plants has raised many questions concerning propagation, dormancy, flower initiation, and general patterns of growth and development. Cathey (1) has shown that general growth habit may be altered to give a more compact plant through the use of Phosphon or by B-nine. He found further that flower initiation could be stimulated after the production of 4-5 flushes of growth instead of the normal 8-9 flushes required under natural conditions, thus making this plant useful as a potted plant. Myhre (3) showed that large applications of phosphate fertilizer increased the number of terminal apices initiating flowers in ‘Cynthia’. In 1920, work in the Netherlands by Luyten and Versluys (2) indicated that leaf and flower initiation occurred early in the growth cycle, May 31 to June 8.

Open Access
Authors: and

Abstract

Time and temp requirements for floral induction in the Amazon lily were found to be 12 days at 29.4°C (85°F) or 3 weeks at 19.4°C (67°F). Greater numbers of bulbs flowered, however, when heated for 16 days at 29.4°C or 3 weeks at 20.6°C (69°F). No detrimental effects, as indicated by percent flowering and flowers per scape, were apparent when bulbs were heated for 4, 5, 6, 7, 8, or 9 weeks at 29.4°C. Total production time was increased as treatment period was extended, but appeared to be definitely modified by season. Days after heating to first flower progressively decreased and total flowers per scape increased as growing conditions improved in spring. The fall crop showed an opposite response.

Open Access

Abstract

Breakage in the floret area of the stem which occurs during harvesting or post-harvest handling in commercially mature snapdragons was investigated. The point of breakage was not influenced by the number of open florets on the stem, provided many unopened buds remain at the apex. Breaking occurred lower on the stem in crops harvested during fall as opposed to summer months. The break point appears to be related to the end of the concentric column of safranin stainable, lignified xylem. Although not without exception, breakage also appears related to flower pigmentation in that anthocyanin (red) containing cultivars tend to break high whereas aurone (yellow) containing cultivars break low in the floret area. These factors suggest a competition for phenyl propanoid precursors which are consumed in both lignification and pigmentation.

Open Access
Authors: and

Abstract

Floral initiation was induced by heating leafy bulbs for 3 weeks at 70 or 75°F, or 2 weeks at 80, 85 or 90°. Bulbs held at 65° remained vegetative. Heating bulbs for periods longer than 2 weeks (5 weeks max) merely extended the time to flower and indicated that little floral development took place until plants were removed from heating.

Open Access

Abstract

Dormant, excised shoot segments from peach [Prunus persica (L.) Batsch.] seedlings previously identified as tolerant, intermediate, or susceptible to Leucostoma persoonii were evaluated for longitudinal canker necrotic length after incubation in contact with a culture of L. persoonii growing on clarified oatmeal agar. The differences in seedling canker necrotic lengths were significant and corresponded with field ratings of disease susceptibility. Seedling Yennoh 1-39 and NJ672017002 1-8 were the most tolerant, whereas Loring 14-20 and Elberta 8-25 were the most susceptible. The excised-shoot assay is sufficiently quick, reliable, and related to field disease reaction to be used as a screening procedure in the breeding of peach cultivars tolerant to L. persoonii.

Open Access

The experiment was conducted at the Cunningham Research Station in Kinston, N.C. (coordinates: N35 18.372; W77 34.937), on Goldsboro loamy sand. Three cultural systems (bare ground + overhead irrigation bare ground + drip irrigation, black plastic + drip irrigation) and seven fungicide treatments were evaluated in a split-plot design with cultural system as the main plot and fungicide treatments as subplots. The cultivar used was `Mickey Lee'. The trial was installed 18 July. Soil moisture was monitored in each of the cultural regimes using soil moisture sensors (Spectrum Technologies, Inc, Plainfield, IL) and rain gauges. The cultural systems using drip irrigation were irrigated to 10 cb starting when soil moisture reached 40 cb. Overhead irrigation was used to maintain at least 2 inches per week total precipitation beginning 12 Aug. Cultural systems and fungicide treatments were replicated 4 times. To prevent gummy stem blight and powdery mildew, Pristine (14.5 oz/acre) and Quintec (6 oz/acre) were alternated with Bravo Weather Stik (2 pt/acre) and Flint (4 oz/acre) on a 7-day interval, beginning 16 Aug. Experimental fungicide treatments were applied using a CO2 backpack sprayer equipped with a 3-nozzle (19-inch spacing) handheld boom with hollow cone nozzles (TXVS-26) delivering 40 gal/acre at 45 psi. Treatments were initiated when the largest fruit were about 6 inches in diameter. All treatments were applied on a 7-day interval with applications on 25 Aug. and 2, 9, 16, and 23 Sept. Plots were inoculated on 12 and 19 Sept. by hand-scattering 0.5 lb of 1-cm cubes of naturally P. capcisi-infected acorn squash fruit per plot. Disease severity was evaluated on 26 Sept. as fruit rot incidence and percent foliar necrosis. Captan was most effective in suppressing fruit rot regardless of cultural regime. Captan and NOA-446510 were both effective in reducing vine collapse across all cultural regimes. Incidence of fruit decay was significantly greater in the bare ground + overhead irrigation (overhead) cultural regime while plasticulture (plastic) and bare ground + drip irrigation (drip) resulted in similar levels of fruit decay and vine collapse. No interaction of cultural regime with treatment was detected. Watermelon stems and foliage are typically very resistant to Phytophthora blight, but significant vine collapse occurred in many plots. P. capsici was consistently isolated from diseased foliage and stems and is considered the primary cause of vine collapse.

Free access

Abstract

In each of 2 cultivars of dry bean, populations of fruits having either low or high abscission potentials were established by removing early opening flowers from half the plants and leaving all flowers on the remainder. Fruits were harvested 4 to 5 days after anthesis and separated according to length, which was negatively correlated with abscission potential. Abscisic acid (ABA), phaseic acid (PA), and dihydrophaseic acid (DPA) contents were determined in methanol extracts of both pods and pedicels, using electron capture gas liquid chromatography. The content of these 3 compounds in pedicels was not significantly affected by cultivar, fruit size or flower removal. ABA content of pods was positively correlated with fruit load but was not related to fruit size. Phaseic acid content increased with fruit size and with fruit load but was not affected by cultivar. Content of DPA was unaffected by pod size or fruit load. We conclude that levels of extractable ABA, PA, and DPA do not regulate fruit abscission in dry bean.

Open Access

Abstract

Open-pollinated progeny from 15 peach (Prunus persica) cultivars, two peach × P. kansuensis hybrids, and one peach almond (P. amygdalus) hybrid were evaluated for their cold hardiness and for tolerance to Cytospora canker following artificial inoculation with Leucostoma persoonii. Winter hardiness was negatively correlated with canker necrotic length (r = −0.26**) and positively correlated with canker rating (r = 0.26**), as indicated by qualitative ratings. The half-sib families differed for canker necrotic length following fall inoculation, indicating that individuals with increased tolerance to L. persoonii canker could be selected from the population. Progeny from the cultivar Yennoh exhibited the shortest canker necrotic length following fall inoculation, and all the inoculated branches were visually healthy. ‘Yennoh’, a plant introduction from Russia, may have a higher tolerance to Leucostoma than has previously been found in U.S. germplasm.

Open Access

Abstract

A computer system consisting of several programs and files, developed for management of information generated in all phases of a dry, edible bean (Phaseolus vulgaris L.) breeding program, is described. The interactive system both produces field books and prints labels for field stakes and planting and harvesting bags.

Open Access

Sixty clones (four clones from each of 15 provenances) were micropropagated and planted in replicated plots in lowland and upland sites in Carbondale, IL in 1991. Data were collected on tree growth, including basal caliper, height, branching, crown volume, dates of bud break, bud set, and leaf fall. There were significant and strong positive genotypic and phenotypic correlations between tree height and basal caliper throughout the three years of growth. During 1993, bud break was not significantly correlated with any growth parameters. After three years in the field, tree height was significantly negatively correlated with the amount of callus that had formed after one month during the in vitro micropropagation phase. However, all shoots that formed in vitro were of axillary origin.

Free access