University of Nevada Cooperative Extension (UNCE) faculty members have taught horticulture to inmates of correctional facilities for over 8 years. The training material used was the Master Gardener curriculum. Because inmates in Nevada have few opportunities to meet requirements for certification as Master Gardeners, this program was described simply as a horticulture class. Over the past 3 years, we have redirected it toward job readiness to assist inmates after release. The curriculum was first expanded to do intensive teaching on such topics as irrigation, landscape plant selection and maintenance, and problem solving. Even with these changes, horticulture jobs generally limited to low-paying, entry level ones. To improve employment opportunities, UNCE obtained the involvement of the Nevada Department of Agriculture. After inmates have passed the horticulture program, they may take the state pesticide applicator training and examination. This year, a mini course in “Developing a Business Model” will be added to the initial curriculum. To date, 36 inmates have received PAT certification. Conversations with potential employers indicate that this significantly enhances their likelihood of employment at a higher-than-entry level.
Measurements of flowering, yield, vegetative and root growth were begun in Spring 1992 to establish a phenological model for `Hass' avocado. Although rootstock (Thomas', Topa Topa', Duke 7' and `D9') did not affect the timing or intensity of bloom, differences in yield were observed. Flowering occurred in March - April in both years, although the intensity of bloom in 1993 was drastically reduced due to an extremely heavy 1992-93 crop. Vegetative flushes occurred in April (following bloom) and July in both years. In 1993, however, cumulative growth was ca. 10-fold greater. Rootstock did not affect the timing or intensity of vegetative growth in either year. In both years, vegetative growth preceded root growth. In 1992, there were no differences detected in the timing or intensity of root growth related to rootstock. In 1993, however, the `Topa Topa' rootstock produced more roots throughout the growing season. The timing and intensity of root growth during the spring flush were similar in both years. During Fall 1993, root growth rates, however, were consistently higher than those observed in 1992. Additionally, while root growth ceased in November 1992, roots have continued to grow through January 1994.
Monthly samples were taken from 9-year-old `Hass' avocado trees on Duke 7 rootstock grown at the UC Southcoast Research and Extension Center in Irvine, Calif. Changes in starch and total soluble sugars were monitored from fine and coarse roots, trunk (above the bud union), small diameter stems, leaves, and fruit. When possible, seasonal carbohydrate changes were compared to root and shoot flushing patterns. In all of the vegetative plant organs monitored, total soluble sugars accounted for most of the carbohydrate. Starch accounted for ≈10% of the sample dry weight, whereas the total soluble sugars accounted for ≈18%. D-mannoheptulose and perseitol, both C7 sugars, were the predominant soluble sugars throughout the year. Fructose, glucose, and sucrose accounted for <5% of the total soluble sugars. During fruit development, soluble sugar content of the exo- and mesocarp tissues >25% of the dry weight. The significance of these findings will be discussed in relationship to tree phenology and carbohydrate partitioning.
We performed an economic analysis of five orchard production systems [Slender Pyramid/M.26 (840 trees/ha), Vertical Axis/M.9 (1538 trees/ha), Slender Axis/M.9 (2244 trees/ha), Tall Spindle/M.9 (3312 trees/ha), and Super Spindle (5382 trees/ha)] using composite yield and labor usage data from several replicated research plots in New York state. Other costs and fruit returns were averages from a group of commercial fruit farms in New York state. The systems varied in costs of establishment from a low of $18,431/ha for the Slender Pyramid system to high of $47,524/ha for the Super Spindle system. The large differences in establishment costs were largely related to tree density. All of the systems had a positive internal rate of return (IRR) and net present value (NPV) after 20 years. They ranged from a low of 7.5% IRR for the Slender Pyramid system to a high of 11.1% IRR for the Slender Axis system. Profitability, as measured by NPV, was curvilinearly related to tree density with intermediate densities giving greater profitability than the highest densities. The optimum density was 2600 trees/ha when NPV was calculated per hectare, but only 2200 trees/ha when NPV was calculated per $10,000 invested. The earliest break-even year was 10 for the Slender Axis and Tall Spindle systems. The latest break-even year was 13 for the Slender Pyramid. An estimate of the number of hectares required to produce a $100,000 annual profit to the business was 222 for the slender pyramid system and 84–104 ha of the three best systems (Super Spindle, Tall Spindle, and Slender Axis). The analysis revealed that efforts to control establishment costs of land, trees and support system can substantially increase lifetime profits.
Phytophthora cinnamomi Rands, the causal pathogen of phytophthora root rot (PRR) of chestnut, is one of the main obstacles to growth of american chestnut [Castanea dentata (Marsh.) Bork.] in the southern part of its distribution. To facilitate introgression of PRR resistance of chinese chestnut (C. mollissima Blume) into a C. dentata genetic background, we assessed the disease resistance of 10 interspecific hybrid families derived from potentially resistant C. mollissima cultivars. Hybrid progeny were inoculated with P. cinnamomi in the nursery and assessed for root lesion severity after 1 year of growth. Asymptomatic plants were transplanted to a P. cinnamomi-positive orchard and evaluated for survival midway through the following growing season. During the nursery experiment, 8 of 10 hybrid families were not significantly different from susceptible C. dentata controls for average disease resistance scores. However, multiple asymptomatic individuals were identified in each of the eight families. Two of the 10 hybrid families were not significantly different from the resistant C. mollissima and C. henryi controls. In the P. cinnamomi-positive orchard, the prescreened hybrid families displayed a greater proportion of survivors than backcross families that had not been prescreened for P. cinnamomi resistance. Hybrid plants that have survived 2 years of growth in P. cinnamomi-infested potting media and soils represent an important step toward the production of genetically diverse chestnut populations in the southeastern United States that combine the PRR resistance of C. mollissima with the morphology and local adaptation of C. dentata.
Three experiments were conducted on `Empire' apple (Malus ×domestica Borkh.) to evaluate the effects of hard water, calcium chloride (CaCl2), water conditioners, surfactants, and captan fungicide on the growth reduction and fruit cracking caused by prohexadione-calcium (PC). Two applications of 63 mg·L-1 PC provided season-long growth control in two studies. Adding a water conditioner to PC reduced shoot growth more than an application of PC in hard or soft water in one New York study. Ammonium sulfate (AMS) and Choice were equally effective water conditioners. PC provided no growth control of water sprouts and had no effect on fruit set or yield. PC applied at 250 mg·L-1 reduced fruit size. `Empire' fruit cracking and corking was severe, despite the use of only 63 mg·L-1 PC in two of the three experiments. This damage was exacerbated by the addition of a water conditioner, however AMS applied with a surfactant but without PC had little or no effect on either the severity or extent of fruit injury. In a third experiment, the addition of surfactants, CaCl2, or captan to 250 mg·L-1 PC plus a water conditioner had no effect on the severity of fruit damage. Fruit cracking caused by PC increased preharvest drop in two of three experiments, and increased postharvest rot in the Geneva, N.Y., experiment where fruit were stored prior to grading. Application of PC plus a water conditioner reduced estimated gross return per hectare for `Empire. We conclude that the fruit injury is caused by the formulated PC product itself under certain environmental conditions, and that this product should not be used on `Empire. Chemical name used: calcium 3-oxido-4-proprionyl-5-oxo-3-cyclohexine-carboxylate [prohexadione-calcium (PC)].
ReTain™, a commercial plant growth regulator containing aminoethoxyvinylglycine, an inhibitor of ethylene production, was applied 4 weeks before normal harvest to `Jonagold' trees and the effects on fruit maturity and quality at harvest, and quality after air and controlled atmosphere storage was investigated. When fruit were harvested from 3 to 6 weeks after treatment, fruit ripening was inhibited as indicated by lower internal ethylene concentrations, delayed starch hydrolysis, and lower levels of skin greasiness. A number of factors indicated that other aspects of fruit metabolism were affected by the compound. Treated fruit were softer than nontreated fruit at the first harvest, and the benefits of ReTain on firmness appeared only at the later harvests. Also, at each harvest date, average fruit weight of ReTain-treated fruit was lower than nontreated fruit. We have investigated the possibility the ReTain and/or the accompanying surfactant, Silwet, inhibited leaf photosynthesis, thereby leading to altered carbon metabolism. Trees were unsprayed, or sprayed with surfactant, and ReTain plus surfactant. No treatment effects on photosynthesis were detected. However, leaf photosynthesis rates were generally low and quite variable. Measurements of fruit diameter confirmed that the increase in fruit volume following treatment was ≈2% less on the ReTain plus surfactant-treated fruit than nontreated fruit. The increase in fruit volume for the Silwet treatment was ≈1.5% less than in untreated fruit. The data indicates a rapid change in fruit volume as fruit changed in color. Inhibition of ethylene by ReTain may be an important factor influencing fruit size.
Researchers have collected a considerable amount of data relating to apple (Malus ×domestica) cultivars and rootstocks over the past 30 years, but much of this information is not easily accessible. The long-term goal of our working group is to increase access to this information using online technology available through eXtension. In eXtension, researchers and extension personnel are developing a community of practice (CoP) to increase the quality and amount of online information for individuals interested in our work [referred to as a community of interest (CoI)]. For this project, our CoI is broadly defined as commercial apple producers, nursery professionals, county extension educators, Extension Master Gardeners, home gardeners, and consumers. Our CoP is developing diverse educational tools, with the goals of increasing productivity, profitability, and sustainability for commercial apple production. Additionally, we will provide other members of our CoI access to research-based, reliable information on the culture of apples. We chose to begin our focus on cultivars and rootstocks adapted to the eastern United States and will add other U.S. regions as our resources and interest in our project grows.