for MBr + Pic, whereas the performance of the soil-applied metam was even lower. Recently, various reports have suggested improved MK performance on nutsedges ( Vaculin et al., 2003 ). However, MK rates, distribution in the soil, water delivery volumes
Bielinski M. Santos and James P. Gilreath
Christopher S. Brown, William M. Cox, Thomas W. Dreschel, and Peter V. Chetirkin
A nutrient delivery system that may have applicability for growing plants in microgravity is described. The Vacuum-Operated Nutrient Delivery System (VONDS) draws nutrient solution across roots that are under a partial vacuum at ≈91 kPa. Bean (Phaseolus vulgaris L. cv. Blue Lake 274) plants grown on the VONDS had consistently greater leaf area and higher root, stem, leaf, and pod dry weights than plants grown under nonvacuum control conditions. This study demonstrates the potential applicability of the VONDS for growing plants in microgravity for space biology experimentation and/or crop production.
Kimberly K. Moore, George E. Fitzpatrick, and Jane E. Slane
The University of Florida College of Agriculture and Life Sciences offers the Bachelor of Science degree program in Environmental Horticulture at the Fort Lauderdale Research and Education Center (FLREC). Instructors at the FLREC deliver course work and course work is also presented using a variety of distance education (DE) technologies. These DE technologies include interactive video conferencing, videotape, and web-based courses. The question often arises as to how many courses should be delivered using DE versus live onsite instruction. This survey was conducted to ascertain how students perceive the quality of education they are receiving using a mixture of delivery methods.
J.R. Clark, J. Naraguma, and R.A. Allen
A planting of sawdust-mulched highbush blueberries (cv. Bluecrop) was established on a Captina silt loam at the Univ. of Arkansas Research and Extension Center, Fayetteville, in 1994. Nitrogen rate and method of delivery treatments were begun that year and continued through the first two fruiting years (1996 and 1997). Rates included 0, 67, 134, 201, and 268 kg·ha-1 N using ammonium sulfate during the fruiting years (one-half and two-thirds these rates in 1994 and 1995, respectively), and methods of delivery included dry, surface-applied, and fertigation. Total N for the year was applied in three applications for the dry application and in 12 applications using fertigation. Neither yield nor berry mass were statistically significantly affected by N rate or method of delivery. Also, method of delivery had little effect on foliar levels of any macro- and microelements. Rate of N influenced foliar N most years, with the highest N rate increasing foliar N the greatest. The N rate required to consistently achieve adequate foliar N levels (minimum of 1.6% N) was 134 kg·ha-1. Foliar levels >2.0% were common with the two highest N rates. Foliar Mg and Mn were also influenced by N rate, with the lowest Mg level found for the highest N rate, while excess foliar Mn (800 to 100 ppm) was common with the higher N rates in 1997.
John G. Richardson, James Stephenson, Gwyn Riddick, Allen Caldwell, and Maurice McAlister
To provide educational opportunities for small and part-time farmers, a project was implemented using selected extension delivery methods. Individual methods or combinations of these were used to meet farmer informational needs. A comparison was made between person-to-person and self-directed (or nonperson-to-person) methods to see which means of receiving extension information farmers preferred. Findings indicated that person-to-person methods were not as useful as the self-directed methods.
Ellen B. Peffley, Kevin Lombard, Cynthia McKenney, and Richard Durham
A plant propagation course was developed for delivery on the World Wide Web. Plant Propagation Methods is one of two foundation courses required of students with either a major or minor in horticulture. The course is accessed via the Texas Tech Univ. Horticulture website, www.pssc.ttu.edu. The delivery software is Web-CT Tutorial and access is password protected. The course has been offered two semesters, Fall 1999 and Spring 2000. Overall, student evaluations have been very favorable. The ratings for the first time offering were a 100% excellent rating was given for stimulating student interest and concepts pointed out; 67% excellent rating for effectiveness of the course, presents challenging ideas, stresses important points, uses visual materials, defines new terms, and provides an overview/objective. Students gave an overall rating of good for the organization of the course. The only negative response by the students was that they said the class was very hard because it was not in a structured classroom setting.
Maritza I. Tapia, P.E. Read, H.F. Kaeppler, and P.L. Herman
Direct DNA delivery via microprojectile bombardment has been successfully used to transform a wide range of species. Transformation using this system is dependent on the optimization of several parameters. These parameters involve the explant, the gene construct, and parameters in the bombardment system. DNA was delivered into bisected axillary buds of grape hybrids `Chancellor' and `Valiant'. Target tissues were bombarded with gold microprojectiles coated with GUS::NPTII fusion gene construct(pBI426). Several experiments with varying parameters were conducted in order to increase the frequency of DNA delivery. Data were analyzed as a completely random design with 6 single petri dish as a replication and 50-60 bisected axillary buds per replication in each treatment. The treatment design was the single-factor method. Higher frequencies of transient transformation were obtained using microprojectiles of 1.6 μm diameter, adding 0.15 m mannitol and 0.15 m sorbitol, under a pressure of 68.6 cm Hg and a target distance of 6 cm. After 40 days on the selection medium containing 50 mg kanamycin/L regenerated plantlets were obtained and 40% of them expressed the GUS gene. The biolistic approach using bisected axillary buds as target tissue could be a method to achieve stable transformation and transgenic grape plants.
Sharon Henss*, Jayne Zajicek, and R. Daniel Lineberger
The performance and satisfaction of students enrolled in a traditionally structured lecture/lab floral design course and a Web-based version of the same course were compared. Students were assigned randomly to course sections by available seating. Data collected included a demographic survey, design and course evaluations, and test grades. Significant differences were noted in class grades, with students in the traditionally taught course outperforming the Web-based students in both lecture and lab grades. Results from a survey instrument designed to determine whether students were suited to the distance learning environment (given only to the Web-based students) indicated a direct correlation between distance preparedness and course grades. A higher level of distance course preparedness correlated with a higher grade in the course. There was also a direct correlation between grades and whether the student was in the course with the delivery method they preferred. Students who were assigned to the course they preferred had significantly higher grades than students who did not. These results indicate that overall, a course such as floral design may be more effectively taught through traditional teaching techniques. However, certain students with adequate computer skills and a preference for Web-based courses may be successful in courses such as floral design.
Robert D. Berghage, Alan Michael, and Mike Orzolek
Current and future plans for reductions in federal and state funding suggest that government supported programs must find ways to reduce costs while maintaining or expanding programs. The current model of extension, with an agent for each commodity in every county is not likely to survive. Furthermore, the days when university-based specialists could afford to make house calls also are probably limited. Yet, the need for extension support in the floriculture industry is as great as ever. Increased chemical costs and regulatory pressure are restricting grower options and making it increasingly important that information dissemination and technology transfer occur in timely and appropriate ways. To try to meet the needs of the floriculture industry in Pennsylvania, we have begun a program to help develop independent greenhouse crop management associations to work with milti-county and university-based extension specialists to improve program delivery to the member greenhouses. The first of these associations has been established in the Capital Region in central Pennsylvania and is providing IPM scouting and crop management services to member greenhouses. Development of associations and linkages with and the role of extension are discussed.
Hideyuki Takahashi, Christopher S. Brown, Thomas W. Dreschel, and Tom K. Scott
Orientation of root growth on earth and under microgravity conditions can possibly be controlled by hydrotropism-growth toward a moisture source in the absence of or reduced gravitropism. A porous-tube water delivery system being used for plant growth studies is appropriate for testing this hypothesis since roots can be grown aeroponically in this system. When the roots of the agravitropic mutant pea ageotropum (Pisum sativum L.) were placed vertically in air of 91% relative humidity and 2 to 3 mm from the water-saturated porous tube placed horizontally, the roots responded hydrotropically and grew in a continuous arch along the circular surface of the tube. By contrast, normal gravitropic roots of `Alaska' pea initially showed a slight transient curvature toward the tube and then resumed vertical downward growth due to gravitropism. Thus, in microgravity, normal gravitropic roots could respond to a moisture gradient as strongly as the agravitropic roots used in this study. Hydrotropism should be considered a significant factor responsible for orientation of root growth in microgravity.