Colorado State Univ. recently underwent the development of a new all university core curriculum. All faculty were encouraged to submit proposals for new courses or revised courses, which would be reviewed for inclusion under specified categories. Basic Horticulture was redesigned te emphasize the scientific method, the understanding between science and society, and the use of handson and inquiry-based instruction in the laboratory. Horticultural Science is now an applied science course that includes the use of hypothesis formulation, experimentation, observation, data collection, summation and presentation in scientific format of reports of at least three laboratory exercises, as well as extensive general observation and presentation in both written and oral format. It teaches science in the context of everyday interaction with the environment in which the student lives, the interior and exterior plants that surrounds the student at CSU, and the controversies as well as the health aspects that surround the production of foods derived from plants that require intensive cultivation. Examples of such issues include sustainability, the organic movement, genetically modified organisms, ground water pollution form overfertilization, and water usage for landscaping and golf courses in a water short region. A review of the revisions as noted above and the use of technology in teaching the course will be presented.
The food crop concentration in the horticulture major was revised in response to discussions with students, faculty, and county agents to emphasis more service learning. A requirement for an internship or practicum was added. The practicum entails the design, maintenance, and data collection of the vegetable and small fruit display gardens. Emphasis will be on sustainable production and on collection of information for use in extension fact sheets for the citizens of Colorado. Other changes include the modularization of the commodity courses to provide greater flexibility and the addition of a capstone course. The capstone course will involve greater interaction with industry in the state and has a requirement for the development of both an enterprise budget as well as a production plan for a commercial operation.
Internship credit has been offered for nearly 30 years. In more recent years, it has been formalized with specific guidelines developed in setting up an individual student program. Internship opportunities are facilitated through a career day, which has moved from fall to spring semester in which over 25 firms come on campus to present their opportunities. A detailed packet of information is distributed to the perspective intern and cooperator. A memorandum of agreement is developed with student, cooperator and internship coordinator which details credit, description of the program and hourly wage. Students are required to submit weekly reports and upon returning to campus must present an oral report to a student group and a written report to the internship coordinator. The cooperator does a summary evaluation, which is submitted to the coordinator. A final interview with each student is done with the internship coordinator and a S/F grade is assigned.
Hrvoje Rukavina* and Harrison Hughes
Efforts are ongoing at Colorado State Univ. to develop cultivars of saltgrass for turf use. Crossing among genotypes have been limited because of the species' short flowering period that generally occurs in late May or early June. Therefore, this study was made to establish a floral induction procedure for saltgrass to facilitate winter crosses in the greenhouse. The effects of vernalization/photoperiod, nitrogen and burning on the flowering induction of three saltgrass genotypes were investigated in the Colorado State Univ. greenhouse. Genotypes 49 and C66 from South Dakota and Nevada, respectively did not respond to flowering induction treatments. Only genotype A54 from the Colorado Front Range gave adequate response to flowering induction treatments. Saltgrass genotype (origin of clone) is a major factor relative to floral induction with the treatments used. All three treatment factors significantly influenced the number of spikes or flowering in saltgrass clone A54. There was a highly significant effect of vernalization/photoperiod (P < 0.01) and burning treatment (P < 0.01), with a smaller but significant interaction (P <0.05) among these two factors. There was also a significant effect of nitrogen (P <0.05). Burning had a significant influence on flowering only in treatments without vernalization/photoperiod effect. Vernalization/photoperiod levels significantly influenced flowering regardless of the burning treatment. Since flowering induction requirements differ among saltgrass genotypes originating in different areas, further studies will evaluate more Colorado genotypes as well as different lengths of vernalization/photoperiod on efficiency of flower induction.
Fahrettin Goktepe and Harrison Hughes*
Watermelon plants are susceptible to Gummy stem blight disease that considerably reduces yields worldwide. In order to develop non-specific resistance, watermelon cv. Crimson Sweet was transformed with copper inducible isopentenyl transferase (ipt), the rate-limiting step in cytokinin biosynthesis, gene via Agrobacterium tumafaciences (LBA4404). Transformed (ipt) and nontransformed plants were grown at approximately 28-30 °C day, 20-22 °C night and 16 hours daylight under greenhouse conditions. Once the plants initiated new growth both transgenic plants and wild type plants were sprayed with one of three different concentrations (0, 10 & 50 μm) of CuSO4. Plants were sprayed twice to run-off in a twenty-four hour time period before inoculation with the pathogen. Cultures of the pathogen Didymela bryonia (W353) were grown for about 3 weeks and an inoculum containing 105 conidia per mL was sprayed with the prepared suspension until initial run-off in a humidified chamber. The disease symptoms were evaluated after one week with resistance demonstrated in all treated transgenic plants. All nonsprayed transgenic and wild type plants showed similar disease symptoms. Infected leaf samples were surface sterilized and re-cultured on V8 medium. The characteristics of the recovered pathogen confirmed that it was identical to the stock culture of W353. The same experiment has been conducted on seedlings from transgenic (T1 generations) and non-transformed plants. The non-transformed seedlings showed the first disease symptoms on their cotyledons and lower leaves. Disease resistance was observed in seedlings of the treated transformed plants as compared to nontransformed ones.
Fahrettin Goktepe and Harrison Hughes*
The watermelon cv. Crimson Sweet was transformed with the copper inducible isopentenyl transferase, the rate-limiting step in cytokinin biosynthesis, gene via Agrobacterium tumafaciences (LBA4404). Transformed (ipt) and nontransformed plants were regenerated from tissue culture and clonally propagated by the rooting of leaf node cuttings. Twelve plants of each were grown in 1-gal. pots. Once the plants initiated new growth both transgenic plants and wild type plants were sprayed with one of four different concentrations (0, 5, 10, & 50 μm) of CuSO4. The experimental unit was a single plant with three replicates. The growth rate, number of leaves, flowers, lateral shoots, and chlorophyll content were measured weekly for five weeks. Treated transgenic plants had greater numbers of leaves, flowers and lateral branches as well as higher chlorophyll levels. Pollen viability was examined in all treatments with no differences among treatments. Plants of both types were self pollinated to generate seeds. Female flowers were bagged before opening and then selfed. Selfed flowers were bagged for at least two days. The fruits were grown for eight to ten weeks with support. Once they reached maturity, fruits were harvested and fruit shape, flesh color, brix, number of normal seeds, number of colored but empty seeds and number of white seeds were recorded. Significant differences were observed only in seed number between wild type and transgenic (both treated and nontreated,) watermelon fruits. The number of seeds in transgenic watermelon plants treated with CuSO4 was reduced to about 5% to 7% of wild type plants. Transgenic plants which received no CuSO4 had approximately 33% to 50% of the seed of wild type.
Harrison G. Hughes
The merging of the Landscape Architecture Program (LA) with the Department of Horticulture had no effect on visibility of horticulture at Colorado State University and in the state. It did enhance the stature of the merged department as it became second only to the Department of Animal Sciences in terms of undergraduate majors and graduates in the College of Agricultural Sciences. The merger had only a limited impact on the budget. The LA is accredited. Accreditation standards aided the LA in justification of a new position. Since the merger, the Landscape Design and Contracting Program has become accredited through the Associated Landscape Contractors of America (Reston, Va.). Horticulture, which has no accrediting agency, is at a disadvantage in competing for open positions.
Jennifer Crane and Harrison Hughes
Plantlets of Solarium tuberosum L. `Russet Burbank', `Sangre', and `Centennial Russet' were grown in vitro from nodal cuttings. A medium overlay was used to reduce the humidity of the in vitro environment. This treatment was tested for its effect on plant growth and on the rate of water loss from detached leaves. The latter was assayed as indicative of hardening and consequent survival of plantlets once removed from in vitro culture. The paraffin medium overlay reduced the rate of water loss from detached leaves of cultured plantlets, but also reduced root growth.
Imed Dami and Harrison Hughes
Micropropagated grapes (Vitis sp. `Valiant') were subjected to water stress while rooting with the addition of 2% (w/v) PEG 8000. PEG-treated plantlets exhibited reduced growth, as compared to control (in vitro, no PEG), but developed greater leaf epicuticular wax. PEG-treated plantlets had three times the wax level of control. Although treated plantlets showed changes in leaf anatomy, no effect on stomatal frequency or stomatal index was evident. Differences in epidermal cell configuration were also observed among leaves from different treatments. PEG-treated plantlets resembled those grown in the greenhouse, morphologically and anatomically, and exhibited a higher survival rate than control upon transfer to the greenhouse.
Imed Dami and Harrison Hughes
Grape cv. Valiant was micropropagated in an MS medium with and without 2% (W/V) of polyethylene glycol (PEG, MW 8000). Leaf anatomy of control (in vitro, no PEG), treated (in vitro, PEG), field grown and greenhouse grown plants were compared under light microscopy. Cell size, palisade layer formation, relative intercellular air space and apparent chloroplast number varied between the leaves of control and PEG treated (high osmoticum) plantlets. These leaf characteristics in the high osmoticum medium appeared more similar to the leaves of the greenhouse and field grown plants. Leaves from control plantlets contained cells of larger size, lacked normal palisade layer formation, greater intercellular pore spaces and fewer chloroplasts. Leaves of PEG treated plantlets had smaller cells, a more defined palisade layer, reduced intercellular pore spaces and greater number of chloroplasts. Leaves of greenhouse and field grown plants had small cells, a well-defined palisade layer, least intercellular pore space and greatest number of chloroplasts. These results demonstrate that a high osmoticum medium may be used to induce more normal leaf development.