High tunnels are becoming an increasingly important production tool for vegetable, small fruit, and cut flower growers in many parts of the United States. They provide a protected environment relative to the open field, allowing for earlier or later production of many crops, and they typically improve yield and quality as well as disease and pest management. Producers, ranging from small-scale market gardens to larger scale farms, are using high tunnels of various forms to produce for early markets, schedule production through extended seasons, grow specialty crops that require some environmental modification, and capture premium prices. The rapid ongoing adoption of high tunnels has resulted in numerous grower innovations and increased university research and extension programming to serve grower needs. An informal survey of extension specialists was conducted in 2007 to estimate numbers (area) of high tunnels and crops being grown in them by state, and to identify current research and extension efforts. Results of this survey provide an indication of the increasing importance of these structures for horticultural crop production across the country.
Changes in the amounts of F1-V, an antigen fusion protein and a candidate subunit vaccine against plague, and total soluble protein (TSP) in green fruit of transgenic tomato plants were investigated to identify the optimum harvest timing to maximize the F1-V yields. Two T 2 progenies of the transgenic plant, ‘22.11.21’ and ‘22.11.5’, were grown. The F1-V concentration rapidly decreased at the beginning of the green stage and decreased to less than 5% of the initial concentration at the late green stage in ‘22.11.21’. The F1-V concentration also decreased as fruit size increased in ‘22.11.5’, but the pattern of the decrease was linear and different from that in ‘22.11.21’. The concentration of TSP also decreased with fruit growing in both plants. When calculated on a whole fruit basis, the F1-V content linearly decreased with increasing fruit size in ‘22.11.21’. In ‘22.11.5’, the F1-V content per fruit also tended to decrease from the middle to late green stage. Based on these observations, collecting small green fruits without pruning was proposed as a harvest practice that may maximize the F1-V yields. Thus, the optimum protocols for harvesting and pruning for plant-made pharmaceutical production may be substantially different from those currently used in commercial hydroponic greenhouses for fresh market tomato.
Using greenhouse tomato (Solanum lycopersicum) as a model system to produce pharmaceutical proteins, electrical conductivity (EC) of hydroponic nutrient solution was examined as a possible factor that affects the protein concentration in fruit. Transgenic tomato plants, expressing F1-V protein, a plant-made candidate subunit vaccine against plague (Yersinia pestis), were grown hydroponically at high (5.4 dS·m−1) or conventional EC [2.7 dS·m−1 (control)] with a high-wire system in a temperature-controlled greenhouse. There was no significant difference in plant growth and development including final shoot dry weight (DW), leaf area, stem elongation rate, or leaf development rate between high EC and control. Net photosynthetic rate, transpiration rate, and stomatal conductance (g S) of leaves were also not significantly different between EC treatments. For both EC treatments, immature green fruit accumulated DW at a similar rate, but dynamics observed in fruit total soluble protein (TSP) and F1-V during the fruit growth were different between the two ECs. Fruit TSP concentration per unit DW decreased while TSP content per whole fruit increased as fruit grew, regardless of EC. However, TSPs were significantly lower in high EC than in control. Fruit F1-V concentration per unit DW and F1-V content per whole fruit were also lower in high EC than in control. Our results found that increasing EC of nutrient solution decreased TSP including the vaccine protein in fruit, suggesting that adjusting nutrient solution EC at an appropriate level is necessary to avoid salinity stress in this transgenic tomato.
fumigation due to the added expense, management, and negative impact on the environment. Most farms are monitoring and improving soils and using crop rotation as alternatives to soil fumigation. Interest in controlled-environment agriculture (CEA) of
Economics and logistics have greatly reduced or eliminated the ability of horticulture instructors to use field trips or on-site visits as educational tools. This is especially problematic in the field of greenhouse management and controlled environment agriculture, since the facilities and technologies used are essential to the discipline. To address this problem, we developed 15 DVD-based virtual field trips (VFT's) that instructors may use to demonstrate to students the most up-to-date facilities, technologies, and management strategies used in greenhouse management (ornamental and food crops) and controlled environment agriculture (GCEA). Each VFT included a preface with background information about the company, a tour organized by subject chapters, self-examination, and a teacher's guide with additional information and case studies. Each land-grant institution with an instructional program in greenhouse management of controlled-environment agriculture will be provided a free copy of each VFT, which will benefit all instructors of GCEA in the United States.
February ( Korczynski et al., 2002 ). Supplemental lighting is often needed to produce high-quality crops in controlled-environment agriculture but can substantially increase production costs. For example, van Iersel and Gianino (2017) estimated that the
Our inability to control adequately the greenhouse environment is probably the main reason for the present interest in the use of controlled environments for commercial production. Actually the controlled environment concept is not revolutionary, since it can be regarded as a logical step in the evolutionary development of protected cropping, i.e., cold house to heated house, to heated house with supplementary lighting to controlled environment growing room. Many of the chambers used in controlled environment agriculture in operation today were built after the grower tried supplementary lighting in the greenhouse, and found that he needed a greater degree of control than the present method.
Agricultural Experiment Station paper D-03130-07-96, supported by State funds and CCEA, the Center of Controlled Environment Agriculture, and NJ-NSCORT. Reference to commercial products implies no endorsement, nor discrimination of other products.
The diversity of coverings for the greenhouse and other plant production structures has increased dramatically during the past 4 decades. This has resulted from the availability of new types of covering materials and enhancements of previously existing materials, as well as the demands for technological improvements within the expanding controlled environment agricultural industry. The types of coverings currently available are dominated by plastics. These range from traditional glass to the recent advent of polymer plastics, such as thin films or multilayer rigid thermoset plastic panels. Available enhancements such as ultraviolet radiation (UV) degradation inhibitors, infrared radiation (IR) absorbency, and anti-condensation drip surfaces, as well as their physical and spectral properties are discussed. The selection of specific covering alternatives has implications for the greenhouse superstructure and its enclosed crop production system.
Center for Complementary and Alternative Medicine. CEAC Paper D-412380-01-06, Supported by CEAC, The Controlled Environment Agriculture Center, College of Agriculture and Life Sciences, The University of Arizona. Special thanks to Bruce Walsh at the