Search Results

You are looking at 31 - 37 of 37 items for

  • Author or Editor: Tim D. Davis x
Clear All Modify Search

Seeds of Aquilegia chrysantha Gray were germinated under a variety of temperature regimes. Germination was nearly 90% under a day/night cycle of 25/20C, but was reduced to ≤ 40% under constant 25C or a 25/10C day/night cycle. With days between 25 and 29C (night = 20C), germination percentage dropped gradually to ≈ 60% with increasing temperature. With days >29C, germination declined dramatically such that no germination occurred at 31C. Neither kinetin (4.6 to 46 μm) nor ethephon (6.9 to 207 μm) was able to reverse the inhibitory effects of 33C days. Our results indicate that germination of A. chrysantha seed is sensitive to temperature and that germination ≈ 75% can be obtained under a 25 to 27C day/20C night regime. Chemical names used: 2-chloroethylphosphonic acid (ethephon); 6-furfurylaminopurine (kinetin).

Free access

Factors affecting the greenhouse propagation of firebush (Hamelia patens) by leafy stem cuttings during winter were studied. Without bottom heat (BH), mid-day rooting medium temperature was 22 ± 3 C. About half of the auxin-treated cuttings without BH rooted. Maintaining the rooting medium at 29-39 C increased rooting for auxin-treated cuttings to 96-100% and increased root length and visual rating scores several-fold. Rooting percentage, root length, and visual ratings were consistently high in perlite and low in peat. Stem-tip cuttings and sub-terminal stem segment cuttings with basal stem diameters of 3-5 mm rooted slightly better than stem segment cuttings with basal diameters of 6-8 mm. Stem-tip cuttings not treated with auxin but with BH had rooting percentages of 81-86%. Treatment of stem-tip cuttings with auxin generally yielded 90% rooting or above. Despite this, plants grown from auxin-treated cuttings were indistinguishable from plants grown from non-treated cuttings 2 months after the rooting period. Of the variables studied, BH had the most dramatic effect on rooting of firebush cuttings during winter months.

Free access


A 2-year study involving 15 garden vegetables and 5 different-sized gardens was conducted to assess land, labor, and production efficiency. As garden size increased, total production increased, but yield per unit area decreased. Relative labor inputs varied with garden size, but were greatest for harvesting (38%) followed by planting (23%), miscellaneous (22%), and weeding (17%). The highest production in relationship to labor and land use was obtained with beets, carrots, cucumbers, onions, tomatoes, and summer squash. The poorest yielding crops were pole and bush beans, sweet corn, peas, peppers, and radishes. Total vegetable yield for the 2-year study averaged 6.2 kg/m2.

Open Access

Plant trialing and marketing assistance programs have become popular in recent years with several state and some regional programs emerging. Successful implementation requires considerable labor, facilities, and monetary resources for evaluation of large numbers of taxa over several years to ensure that plants are well adapted to the region of interest. Research and development funds, dedicated facilities, and cooperator commitment to trialing programs can be limiting during the early years of the programs. Involvement in plant trialing programs allows students to be exposed to plot layout planning, statistical design, plant maintenance, data collection and analysis, and professional communication of trial results. Construction of facilities for conducting plant trials, growing plants for use in trials, trial installation, and maintenance of plants all provide practical hands-on horticultural training. Replicated plant trials provide the latest information on regionally adapted taxa for inclusion in classroom instruction and publications. Plant trialing programs benefit from labor assistance, development of dedicated facilities, and the opportunity to share equipment and supplies among teaching, trialing, and student research projects.

Full access

The Coordinated Educational and Marketing Assistance Program identifies outstanding landscape plants for Texas and provides support for the nursery industry, thereby making superior plants available to Texans. CEMAP funding comes directly from industry and from consumers through the sale of plant tags bearing the Texas Superstar logo. Additionally, the Texas Nursery and Landscape Association and Texas Department of Agriculture is conducting a Texas Superstar publicity campaign. An estimated $10 million in new plant sales have been generated during the first 10 years of this program. Because plants are chosen based on their performance under minimal input conditions, Texas SuperStars greatly reduce their impact on the urban environment.

Full access