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Regulations restricting water use, competition for water with large urban sector, coupled with extreme high temperatures have placed a large strain on farming areas in south Texas. In addition, consumer demand for healthy vegetables has increased. The objective of this work was to determine yield and fruit quality to deficit irrigation rates and irrigation systems on poblano pepper cv. Tiburon. In 2002, an experiment was conducted at the TAES-Uvalde with a Center pivot using three irrigation rates, 100%, 80%, and 60% evapotranspiration rates (ETc). Transplants were established on beds 1.0 m apart with plants within rows 45 cm apart. In 2003, we compared production efficiency of four irrigation systems in a urban-rural environment near San Antonio. Beds were 0.9 m (single-row) or 1.8 m (double-row) between centers. Irrigation systems were: 1) furrow irrigation with one line/single beds, 2) subsurface drip (SDI)-no mulch, with one line/single bed, 3) SDI-no mulch, with two lines/double bed, and 4) SDI-white mulch with two lines/double bed. In 2002, summer ratooning of the spring-planted crop under deficit irrigation (<100% ETc) allowed a fall crop with a 2.0 fold yield increase, larger fruit size (greater than 10 cm length) and significantly lower defects caused by sunburn or blossom end rot compared to summer production. In 2003, SDI-white mulch had a 2.4-fold yield increase and 760 mm water savings compared to furrow. Fruit vitamin C content was not affected by irrigation, however, mature red fruits had a 3.6 fold increase compared to mature green fruits. Combining deficit irrigation with ratooning we were able to produce marketable poblano fruits. Additional water savings and increased yield were demonstrated by SDI technology.

Adoption of technology to achieve environmental stewardship and remain competitive is a high priority for greenhouse businesses. Zero runoff subirrigation (ZRS) technology offers great promise to manage fertilizer inputs while improving production efficiency. This study applied economic engineering methodology to quantify costs and returns associated with adopting ZRS systems and compare profitability of producing crops using alternative ZRS systems for greenhouse operations in the northeastern and north central United States. The production models showed that using ZRS systems to grow greenhouse crops can be profitable if growers select a system best suitable for their crop choices. Among the four ZRS systems studied (ebb-and-flow rolling benches, Dutch movable trays, flood floors and trough benches), the Dutch movable tray system returned the highest profit per square foot week (SFW) greenhouse area for small potted plant production ($0.244/SFW), and the flood floor system returned the highest profit when producing large potted plants ($0.002/SFW) and bedding crop flats ($0.086/SFW). The trough bench system was least profitable had the lowest profit for the two applicable crop categories—small potted plants ($0.183/SFW) and large potted plants (–$0.006/SFW). Sensitivity analysis showed that changes of cost variables generally did not affect the profitability rankings for alternative ZRS systems. Except for labor costs, as the hourly wage increased, the Dutch movable tray system gained advantages for small potted plant and large potted plant production. Among selected costs variables, changes in labor costs and tax rate had the highest impact on the profitability of small potted plant production, and changes in labor costs and initial investment costs had the highest impact on the profitability of large potted plant and bedding crop flat production.

Potato (Solanum tuberosum) is a high value crop in Florida. It consistently ranks in the top five valued vegetable crops produced in the state. The identification of new potato varieties that improve production efficiency is an imperative because of constantly evolving market and production demands. A chip potato variety evaluation experiment was conducted in northeast Florida in 2002 to compare the production characteristics of industry standards to advanced selections. The potato varieties evaluated in this experiment were bred specifically for processing by the potato chip industry. The experimental design was a four (site) by five (variety) factorial with four replications at each site. The sites were the University of Florida's research farm in Hastings, FL and three commercial farms in the surrounding area. Potato varieties were two seed sources of `Atlantic', as well as, `Snowden', B0564-8, and B0766-3. Marketable yield for each variety was 39.4, 33.4, 38.4, 33.6, and 33.6 t·ha^-1 (351, 298, 343, 300, and 300 cwt/acre), respectively. Total yield of B0564-8 was statistically equivalent to an `Atlantic' standard at all four locations and similar to `Snowden' at three of four locations. Specific gravity of B0564-8 and B0766-3 was significantly lower than that of `Atlantic' from both sources but within acceptable range for chip potatoes. B0564-8 tubers had the highest overall appearance ratings and the most consistent size and shape. B0564-8 and B0766-3 tubers had a significantly lower percentage of hollow heart and internal heat necrosis than `Atlantic' tubers. This resulted in overall better chip ratings for the numbered entries compared to `Atlantic' tubers. A potential fit for B0564-8 and B0766-3 in northeastern Florida production may be as a late season chip variety when the potential for the development of internal heat necrosis increases.

Potato (Solanum tuberosum) is an important agricultural crop for Florida. From 1996 to 2000, the winter and spring potato crop was grown on an average of 15,782.7 ha (39,000 acres) and valued at $117 million. Variety evaluation and selection is an important tool to improve production efficiency and increase the competitiveness of Florida growers. A red-skinned potato variety evaluation was conducted in northeastern Florida in 2002. The experimental design was a 4 (site) × 5 (variety) factorial with four replications at each site. The four sites were the University of Florida's Plant Science Research and Extension Unit and three local commercial farms. Potato varieties in the trial were `Red LaSoda', `LaRouge', B0984-1, B1145-2, and B1758-3. Marketable tuber yields were 36.3, 35.6, 30.2, 20.3, and 21.4 t·ha^-1 (324, 318, 269, 181, and 191 cwt/acre) respectively, with tuber yields of the two named varieties significantly higher than the numbered entries. Specific gravity ranged from 1.060 (`Red LaSoda') to 1.070 (B0984-1). There were no significant differences among entries for total cull weight or the incidence of hollow heart, brown rot, or corky ringspot. However, a higher percentage of B0984-1 tubers showed symptoms of internal heat necrosis than all other varieties. Potato varieties ranked from lowest to highest in overall appearance were `LaRouge', `Red LaSoda', B1758-3, B0984-1, and B1145-2. Higher appearance ratings in the numbered entries were attributed to darkerred skin color, rounder tuber shape, and shallower eyes compared to `Red LaSoda' and `LaRouge'. `Red LaSoda' and `LaRouge' will continue to be recommended as the standard redskinned potato varieties for Florida. However, B0984-1 and B1145-2 had desirable characteristics and should be planted in larger plantings to further evaluate quality and production characteristics.

Although zero runoff subirrigation (ZRS) technology has great promise to manage fertilizer inputs while improving production efficiency in greenhouse operations, high initial investment costs and inadequate technical background are major impediments for initiating the change. In a world of uncertainty, greenhouse operators face the challenge of making an optimal investment decision to satisfy environmental compliance expectations and meet the companies' financial goals. Using Monte Carlo simulation, cost risk was analyzed to compare the relative risks of investing in alternative ZRS systems for greenhouse crop production. An investment model was defined for greenhouse production with alternative ZRS systems. Each cost variable was allowed to vary based on a probability distribution. Random numbers were generated to determine parameters for the probability distributions for the uncertain variables. The simulation process was repeated 300 times for each production model. Simulation results showed that among the four ZRS systems studied (ebb-and-flow benches, Dutch movable trays, flood floors, and trough benches), the Dutch movable tray system returned the highest average profit for small potted plant production and the flood floor system returned the highest average profit for large potted plant and bedding crop flat production. Risk of the production models were compared by the variability of simulation results. The Dutch movable tray system is the least risky for small potted plant production, and the flood floor system is the least risky for large potted plant and bedding crop flat production. Despite its low initial costs of adoption, the trough bench system was least competitive as a ZRS technology for a greenhouse operation because of the relative low profitability and high risk of production due to volatile profitability.

Abstract

The influence of Mailing (M)26, M9, M27 rootstocks and stempiece/rootstock combinations M9/Malling-Merton (MM)106, M9/MM111, M27/MM106, and M27/MM111 on growth, leaf nutrition, and fruit quality of ‘Empire’ apples (Malus domestica Borkh.) was evaluated. After 8 growing seasons, height and spread of trees on M26, M9/MM106, M9/MM11, M27/MM106, and M27/MM111 were similiar and were greater than those of trees on M9 and M27. Mn concentration in leaves from trees on M27 was higher than that of leaves from trees on other rootstock and stempiece/rootstock combinations. Production of trees on M26, M9/MM106, and M27/MM106 was greater than that on M9/MM111, M9, and M27. When fruitfulness was related to trunk area, trees on the various rootstock and stempiece/rootstock combinations did not differ in production efficiency. Effect of rootstock or stempiece/rootstock on fruit size was inconsistent. Fruit from trees on M27/MM111 entered in to their climacteric later than those from trees on M26 and M 27 for 2 years and from trees on M9 and M9/MM106 for 1 year, but the delay was small. No fruit flesh firmness differences were detectable. Soluble solids content of fruit from trees on M27 was higher than that of fruit on M26, M9/MM111, and M27/MM111. Senescent breakdown was more prevelant in fruit from trees on M26 than on M9, M27, M9/MM111, and M27/MM111.

Irrigation of container-grown ornamental crops can be very inefficient, using large quantities of water. Much research was conducted in the 1990s to increase water efficiency. This article examined water management, focusing on three areas: water application efficiency (WAE), irrigation scheduling, and substrate amendment. Increases in WAE can be made by focusing on time-averaged application rate and pre-irrigation substrate moisture deficit. Irrigation scheduling is defined as the process of determining how much to apply (irrigation volume) and timing (when to apply). Irrigation volume should be based on the amount of water lost since the last irrigation. Irrigation volume is often expressed in terms of leaching fraction (LF = water leached ÷ water applied). A zero leaching fraction may be possible when using recommended rates of controlled-release fertilizers. With container-grown plant material, irrigation timing refers to what time of day the water is applied, because most container-grown plants require daily irrigation once the root system exploits the substrate volume. Irrigating during the afternoon, in contrast to a predawn application, may increase growth by reducing heat load and minimizing water stress in the later part of the day. Data suggest that both irrigation volume and time of application should be considered when developing a water management plan for container-grown plants. Amending soilless substrates to increase water buffering and reduce irrigation volume has often been discussed. Recent evidence suggests that amending pine bark substrates with clay may reduce irrigation volume required for plant production. Continued research focus on production efficiency needs to be maintained in the 21st century.

Field experiments were conducted in 1996 and 1997 to examine the effects of plant density on yield and quality of fruit and seeds of muskmelons (Cucumis melo L.). Two open-pollinated cultivars, Noy Yizre'el (Ha'Ogen type) and TopMark (western U.S. shipper type), were grown at plant densities ranging from 0.5 to 16.0 plants/m² under commercial conditions. The highest marketable fruit yields were achieved with plant densities of 2 to 4 plants/m². In contrast, the highest seed yields were obtained at 8 to 12 plants/m². Seed yield index [seed yield (g)/fruit yield (kg)] was used as a parameter to define seed production efficiency. High seed yield was closely related to high value of the seed yield index. High seed yield indexes resulted from high plant densities (up to 12 plants/m²), at which the crops produced many, but relatively small fruit. In all cases, the seed yield per fruit (seed number and seed size) increased with increasing fruit weight. However, the sum of the seed yield of two small fruit was always greater than the seed yield of one, double-sized fruit. There was a clear exception with extremely small fruit (<500 g), which produced both low seed yields and poor seed quality. A positive relationship was found between fruit size and seed size in both cultivars. Nevertheless, relatively small seeds (25 to 30 mg) extracted from relatively small fruit (500 to 1000 g) showed the best performance in terms of germination and emergence percentages and rates, and in the vegetative development vigor of the seedlings.

Interploid hybridization was conducted using `Key' lime [Citrus aurantifolia (Cristm.) Swing.], `Lakeland' limequat hybrid [C. aurantifolia × Fortunella japonica (Thumb.) Swing.], Palestine sweet lime (C. limettioides Tan.), `Etrog' citron (C. medica L.), and seven lemon [C. limon (L.) Burm. F.] varieties as female progenitors and five allotetraploid somatic hybrids {`Hamlin' sweet orange [C. sinensis (L.) Osbeck] × `Femminello' lemon (C. limon)]; `Key' lime × `Valencia' sweet orange (C. sinensis); `Valencia' sweet orange × rough lemon (C. jambhiri Lush); Milam lemon (purported C. jambhiri hybrid) × `Femminello' lemon (C. limon); and `Valencia' sweet orange × `Femminello' lemon} and two autotetraploids [`Giant Key' lime (C. aurantifolia) and `Femminello' lemon] as pollen progenitors. A few tetraploid × diploid crosses were also performed. Thirty-five parental cross combinations were accomplished in 2000, 2001, and 2002. The breeding targets were seedlessness, cold-tolerance, and disease resistance. Triploid hybrids were recovered through embryo culture. Generation of triploid citrus hybrids was affected by several factors including sexual compatibility, cross direction, embryo developmental stage, pollen viability, as well as horticultural practices and climatic conditions. Efficiency of triploid hybrid production was higher in diploid × tetraploid crosses than the reciprocal. Many more triploid hybrids were generated from lemon seed progenitors compared to the other acid citrus fruit progenitors. `Todo el Año', `Lisbon', and `Limonero Fino 49' showed the highest sexual compatibility. Embryo germination rate and normal plant recovery were also higher in lemons as compared to the other seed progenitors. Low winter temperatures might have affected the hybrid production efficiency from tropical acid fruit progenitors. A total of 650 hybrids (mostly triploid) were transferred to soil. The novel genetic combinations of these progenies should be valuable for the genetic improvement of acid citrus fruit (lemons and limes).