Search Results

You are looking at 1 - 10 of 11 items for

  • Author or Editor: J. D. Caldwell x
Clear All Modify Search
Author:

Abstract

Blackberry [Rubus (Tourn.) L. subgenus Eubatus] propagators utilize a variety of asexual techniques and many different types of vegetative material to propagate desirable genotypes. Traditional methods include propagation through removal of sucker plants, tip layering, and various types of cuttings. Although some traditional methods still are used commonly, tissue culture methods eventually may become the preferred means of propagation, especially as techniques become refined and familiar to propagators.

Open Access

Abstract

Certified, fresh-dug plants of ‘Apollo’ and ‘Earlibelle’ strawberries (Fragaria × ananassa Duch.) were set in single plant rows on 23 Sept., 7 Oct., 21 Oct., and 5 Nov. 1982 at in-row spacings of 7.5, 15, 22.5, and 30 cm. After harvest in 1983, plants were mowed and maintained as hill rows or mowed or not mowed for conversion to matted rows. Crown number, leaves, inflorescences and flowers per crown, fruit size, and fruit number and yield were determined in Spring 1984. Mowing had no effect on yields of matted rows, which, except from the 23 Sept. set plants, were higher than hill rows. Hill rows produced larger fruit than matted rows, but the latter had higher fruit numbers and averaged 57 % more crowns per unit area. The 23 Sept. hill row yields were higher than later plantings, but original planting date had no effect on matted row yields. Fruit number of the three later plantings of both training systems and hill row yields decreased as plant spacing increased. ‘Apollo’ had higher yields and individual yield component values than ‘Earlibelle’ in both training systems.

Open Access
Authors: and

Abstract

Certified, fresh-dug plants of ‘Apollo’ and ‘Earlibelle’ strawberry (Fragaria × ananassa Duch.) were set in single plant rows on 23 Sept., 7 Oct., 21 Oct., and 5 Nov. 1982 at in-row spacings of 7.5, 15, 22.5, and 30 cm. Leaf, inflorescence, flower and fruit number per plant, and fruit size and yield were determined in Spring 1983. The highest yield and fruit numbers were obtained from the 23 Sept. plantings. Yields decreased with each delay in planting through 21 Oct., but the affected yield components varied with planting date, plant spacing, and cultivar. Total yield increased as plant spacing decreased for each planting date. Plant spacing had no effect on fruit size.

Open Access

Abstract

Twelve seedling populations involving large, intermediate, and small-fruited parental clones of tetraploid blackberries were evaluated for fruit size inheritance. The amount and type of variation and the significant deviations from the mid-parent means in seedling distributions indicated that inheritance was quantitative with partial dominance for small fruit size. Maximum heritability, estimated by the genetic variance/phenotypic variance, was 0.76. Narrowsense heritability, estimated by regressing progeny on the mid-parents, was 0.62, indicating that most of the genetic variability (82%) was transmittable through the sexual cycle (gametes). These results suggest that simple breeding procedures based on inter-mating parent clones selected on the basis of their phenotypic performance are likely to produce significant genetic gains in fruit size of blackberries.

Open Access

The commercial strawberry Frageria × ananassa and several clones of F. chiloensis and F. virginiana were preconditioned in growth chambers under the following conditions: 500 μmol m-7s-1 PAR and 20° day, 10° night or 30° day and 20° night. After at least 3 weeks of preconditioning at the two different temperature regimes, leaf photosynthetic rate (A) was determined for temperatures ranging from 10 to 35° in 2-3° increments with an open gas exchange system under laboratory conditions. The objective was to determine if F. virginiana and F. × ananassa can photosynthesize at higher temperatures than F. chiloensis, and if any of these would acclimate to higher temperatures. F. chiloensis did not acclimate to higher temperatures, and bad maximum A between 16 and 20°. F. virginiana did acclimate to higher temperatures, with maximum A for the low temp treatment between 18 and 24°, and for the high temp treatment between 24 and 30°. The commercial cultivars of `Earliglow' and `Redchief' acclimated to higher temperature and responded similar to F. virginiana.

Free access

Abstract

The influence of hormone concentration, date of cutting collection, rooting medium, shoot position, cutting type, and wounding on the rooting of semi-hardwood ‘Hayward’ kiwifruit [Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson var. Deliciosa] cuttings was evaluated. The highest percent rooting was obtained with cuttings from the apical (88%) and medial (66%) portion of current season's growth. Higher rooting percentages were obtained when shoots were collected mid-June to mid-July rather than September. Two-node cuttings wounded through the lower bud were given higher root quality ratings than wounded one-node cuttings, although rooting percentages were similar. Treatment with IBA at 4.0 or 6.0 g·liter–1 resulted in similar rooting percentages (58% and 69%, respectively) of two-node cuttings, but root ratings were higher with 6.0 g·liter–1. Cuttings rooted in vermiculite were given higher root quality ratings than those in perlite or 1 peat : 1 perlite (v/v) and had a higher percentage of rooted cuttings than those in peat:perlite. Chemical name used: 1H-indole-3-butyric acid (IBA).

Open Access

Abstract

Net photosynthesis (Pn) rates of greenhouse-grown apple leaves were unaffected for at least 24 hours after shoot detachment. With shoots detached from orchard trees, overnight holding did not affect Pn rates nor stomatal resistance. Use of detached shoots for Pn and dark respiration (Rd) determinations in apple leaves was concluded to be a valid technique.

Open Access

Anthurium cultivars are being produced primarily as cut-flower plants. Whether Anthurium can be used as a flowering interiorscape plant is not well documented. Therefore, five finished Anthurium cultivars were evaluated in interior acclimatization rooms under two light intensities provided by cool-white fluorescent lamps for 12 hours daily: 16 mmol·m–2·s–1 (low light) and 48 16 mmol·m–2·s–1 (high light). Temperature of the rooms was maintained at 24 °C with a relative humidity of 60%. Total number of open flowers and number of senesced flowers were recorded weekly over 5 months. In addition, plant canopy height and width and total number of leaves were measured monthly. Number of open flowers per week ranged from 1.4 to 4.7 under low light and 2.4 to 6.3 under high light. The cultivar Red Hot showed the best performance with a weekly average flower count of 4.7 under low light and 6.3 under high light. All cultivars continued to produce new leaves, ranging from one to five per month under low light and two to five leaves under high light. Leaves were dark green and shiny under the interior conditions. Growth index of `Red Hot' increased 31% under low light and 20% under high light. Results from this study demonstrate that Anthurium can continue to grow and produce flowers under interior environmental conditions. Variation among cultivars indicates that genetic potential exists for selecting improved cultivars based on interior performance.

Free access

Aglaonema is among the most popular tropical ornamental foliage plants used indoors because of its bright foliar variegation, low light and humidity tolerance, and few pests. Aglaonema, however, has been labeled as one of the most chilling-sensitive foliage plants. The dark, greasy-appearing patches on leaves injured by chilling can result in completely unsalable plants. With recent breeding activity, more and more Aglaonema cultivars have been developed and released. How new cultivars respond to chilling temperatures is, however, mostly unclear. This study was undertaken to evaluate cultivar chilling responses to identify chilling-resistant cultivars. Twenty cultivars were chilled at 1.7, 4.4, 7.2, 10, and 12.7 °C for 24 h using a detached single-leaf method and also whole-plant assay. Results indicate that great genetic variation exists among the cultivars, ranging from no injury at 1.7 °C to severe injury at 12.7 °C. A popular cultivar, Silver Queen, is the most sensitive, while the cultivar Stars is the most resistant. There was also a chilling response difference based on leaf maturity. Young leaves showed less injury than did either mature or old leaves. In addition, there was a significant correlation between the single-leaf and whole-plant assay for chilling resistance in Aglaonema'; the single leaf assay could be particularly useful for a quick test.

Free access

Potted anthurium is becoming an important indoor flowering foliage plant because of its unique attractive appearance and continuous growth and flowering under interior conditions. However, an interior environment, with controlled optimal temperatures and relative humidity and living plants, is an ideal niche for pest development. Pests such as thrips and two-spotted spider mite on Anthurium have been great challenges to the interiorscape industry because many pesticides have been rigorously restricted for interior use. Thus, exploiting the genetic potential of cultivar resistance may be the best approach for the control of these pests. In this study, eight of the most popular Anthurium cultivars were evaluated for their resistance to a natural infestation of thrips (Hercinothrips femoralis) and two-spotted spider mite (Tetranychus urticae) under three light levels: 4, 8, and 16 μmol·m-2·s-1, temperatures of 23.8 to 26.7 °C and a relative humidity of 60%. Results indicated that significant resistant differences exist among cultivars. The cultivars most resistant to thrips were not the most resistant to mite and vice versa. Cultivars that exhibited moderate resistance to thrips were also moderately resistant to mite. Low light intensity appeared to be a factor influencing thrips infestation since control plants that grew under a light intensity of 200 μmol·m-2·s-1 had no observed thrips damage. On the other hand, two-spotted spider mite infestation was not influenced by light intensity.

Free access