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Four green apple (Malus domestica Borkh.) cultivars, `Granny Smith', `Mutsu', `Newtown', and `Shamrock', were subjected to a factorial experiment of two rates of nitrogen fertilization and three concentrations of foliar urea sprays for 4 years. The higher rate of N (160 kg N/ha) had no effect on ground color or fruit quality relative to the lower rate of 80 kg N/ha. Urea sprays enhanced green pigmentation in `Granny Smith' and `Newtown' at harvest and retarded yellowing of fruit in all cultivars during air storage at 0C. Response was similar for urea at 0.5% and 1%, and urea sprays did not adversely affect quality. Urea sprays increased fruit N by 23% and 47% for the 0.5% and 1% concentrations, respectively.
The inheritance of resistance to the root lesion nematode [Pratylenchus penetrans (Cobb) Filip. and Stek.] in red raspberry (Rubus idaeus L.) was studied in a four-member half diallel, involving two resistant genotypes and two susceptible genotypes. Estimates of general and specific combining abilities (GCA and SCA, respectively) were determined for nematode densities in roots alone and soil alone, nematode densities per plant, and plant root and foliage biomass. GCA were significant for nematodes in soil and for root and foliage biomass; SCA were significant for nematodes in the soil and for root biomass. Neither GCA nor SCA was significant for number of nematodes in the roots or per plant.
Abstract
Pseudomonas syringae van Hall, an ice nucleation active (INA) bacterium, increased frost susceptibility of tomato (Lycopersicon esculentum Mill.) and soybean (Glycine max L.) when sprayed on leaves prior to low temperature stress. Tomato and soybean plants inoculated with INA bacteria were nucleated and frozen at −4° and −5°C respectively. Control plants that were free of INA bacteria supercooled and survived to −8°. A threshold INA bacterial concentration of about 4 × 105 cells/ml was necessary for ice nucleation. Ice nucleating active bacteria preconditioned at 2° showed a marked increase in efficiency of ice nucleation. Preconditioned INA bacteria had ice nucleation temperatures 5° higher than INA bacteria held at 21°.
Apple fruitlet growth responses to temperature were studied, for different durations following bloom (DAFB), under controlled environment (CE) conditions. Container-grown trees of `Red Delicious', `Golden Delicious', `Braeburn', `Fuji', and `Royal Gala' were placed in different maximum/minimum temperature regimes, ranging from 9/3 to 25/15°C for various periods, including 10–40, 10–80, and 40–80 DAFB. Temperature treatments were selected to identify possible differences between mean and maximum/minimum differential effects Trees were placed outdoors following the CE treatment to allow impacts on subsequent fruit development to be determined. The impact of temperature was dramatic. For example, fruit expansion rate for `Red Delicious' varied from 0.12 mm/day at 9/3°C to 0.98 mm/day at 25/15°C. Furthermore, the cell division phase was considerably longer under cooler temperatures. The influence of post-bloom temperature, for even short durations, was evident at harvest in both fruit size and in different fruit maturity indices. Differences in temperature sensitivity were evident amongscultivars. A detailed model has been developed to integrate the responses that have been determined.
Abstract
Chemicals deposited on foliage varied by a factor of three to five times when sprays were applied with an airblast sprayer to apple (Malus domestica Borkh.) trees in various training systems. Deposits were higher with vertical than horizontal training systems, smaller tree sizes, and less-dense tree canopies of spur-type trees. The Lincoln canopy tree training system prevented good spray penetration because the airblast spray pattern was split by the horizontal nature of the canopy.
The U.S. nursery and landscape industry generates 1.9 million jobs and had an annual payroll of greater than $3 billion in 2002, yet little is known about nursery and landscape workers. This lack of information is even more pressing considering that labor generally accounts for greater than 40% of production costs and 31% of gross sales. Labor shortages, immigration reform, and legal status of employees are widely reported as the industry's most critical issues. We hypothesized that relevant data regarding the nursery industry workforce may raise an appreciation of the industry's diversity, increase political power and public awareness, and help stakeholders evaluate policy decisions and plan corrective strategies in a more informed manner. A total of 4466 self-administered questionnaires were sent in 2006, attempting to reach 30 nurseries in each of nine states with 1561 returned (35% response rate). Hispanics constituted 70% of the average nursery workforce, including general laborers (76%), crew leaders (61%), and sales/managers (others) (21%). Across firms, labor retention was less than 51% after 5 years and only 22% of employees understood English, raising questions regarding availability and access to training. Sixty percent of nursery employees had not received work-related training, although 81% of men and 72% of women were interested, and an association between training and employee retention existed. The highest rated training topic of interest was English/Spanish (respective of Spanish/English primary language respondents). There was a positive correlation between developing fluency and worker turnover, making the laborer attrition rate even more unfavorable for employers who not only lost employees with acquired experience, but also with acquired English skills.