|Dr. Stephen S. Miller|
USDA-ARS-AFRS 2217 Wiltshire Road Kearneysville, WV 25430 Voice: (304) 725-3451 x325
2217 Wiltshire Road
Kearneysville, WV 25430
Voice: (304) 725-3451 x325
Professional Biographical Information:
Ph.D. in Plant Physiology (1971),
M.S. in Horticulture (Pomology) (1968),
B.S. in Agricultural Science (1966),
1979 - present; Research Horticulturist; USDA-ARS, Appalachian Fruit Research Station,
1974 - 1979; Associate Professor of Horticulture and Extension Horticulturist,
1972 - 1974; Horticulturist and Instructor, James Rumsey Vocational
Description of Research Project:
Research goals focus on developing and evaluating cultural management techniques for apple and peach that improve annual cropping and increase efficiency for growers, and enhance the quality of fruit delivered to consumers. Studies focus on integrating cultural management techniques such as cultivar selection, training and pruning, bioregulators, and soil and water management with the whole orchard system. Special emphasis is placed on integrating cultural management techniques with pest control knowledge and practices.
Current Research Topics and Past Accomplishments:
1. Training and performance of new and novel peach tree growth types.
Background: Standard growth habit peach trees are large and have traditionally been trained to an open center spreading system. This management technique results in low tree density per acre and is associated with very low per acre peach yields in the
Goal: Develop training systems for new peach tree growth types that are adapted to higher density planting systems and evaluate the performance of these systems over time.
Approach: New peach tree growth habits (pillar and upright) developed by the AFRS breeder have been planted at various in-row spacings to develop orchards ranging from low to high densities. Several training systems have been imposed on these novel growth habits and a like planting of standard growth habit peach trees for comparison. The field plots utilize sufficient tree numbers and acreage in order to demonstrate the commercial production potential of these novel growth habits for high-density peach production in the eastern
Accomplishments: Field studies demonstrated the potential when planting pillar (also known as columnar) and upright peach tree growth habits at high density with significantly higher yields than conventional standard peach tree growth types.
Dr. Ralph Scorza, Research Horticulturist/Stone Fruit Breeder, USDA-ARS,AFRS-ARS-USDA
2. Evaluate the performance of new apple varieties (cultivars) and develop horticultural management techniques for the most promising varieties.
Background:Commercial apple growers are seeking new varieties with improved pest resistance and high fruit quality that will bring greater returns than many of the current varieties. Consumers are looking for high quality apples with good shelf life and unique flavors. There is a need for the systematic evaluation of new apple varieties developed by breeders or discovered as natural mutations that may fulfill grower and consumer desires.
Goal: Using a cooperative regional project, evaluate a large number of new apple varieties for their horticultural qualities and pest resistance. Identify the most promising varieties for the mid-Atlantic growing region.
Approach: Two identical replicated orchards consisting of 23 apple cultivars or numbered selections were planted in 1995. The first orchard was used to evaluate the horticultural characteristics (growth, yield, and fruit quality) of the newer apple cultivars. The second orchard was used to determine the pest susceptibility (disease and insect) of the newer cultivars. A third orchard was added in 1999 with an additional 20 replicated cultivars with the objective to examine horticultural characteristics. The "rough skin" problem associated with one of the most promising cultivars, 'GoldRush', is being studied in detail and treatments to ameliorate the malady are underway.
Accomplishments: Several new apple cultivars have been identified that are well adapted to the mid-Atlantic fruit growing region. Information on disease and insect susceptibility has been developed and published along with production and horticultural characteristics. Presentations have been made to various fruit growing and professional organizations describing the findings.
Dr. Alan Biggs, Plant Pathologist,
Dr. Henry Hogmire, Entomologist,
3. Develop methods and new knowledge in the use and action of plant bioregulators to affect tree growth and cropping and enhance fruit quality.
Background: Consistent annual cropping in apple requires moderate vegetative growth and annual return bloom. In many apple growing regions of the
Goal: Develop practical methods for using plant bioregulators that affect growth, flowering, thinning, and fruit quality in today's orchard and a better understanding of the mode of action of select bioregulators, particularly those used for thinning.
Approach: Apply thinning bioregulators to apple trees in the field at various times and concentrations and examine the response to fruit set and carbohydrate levels. Subject data from thinning studies to the Cornell Apple Tree Carbon Model. Test low rate multi-spray bioregulator programs as a means for controlled suppression of shoot growth in young apple trees. Evaluate various plant bioregulators and environmentally friendly compounds (e.g., particle films or natural oils) to improve fruit finish in select apple cultivars. Develop novel applications for plant bioregulatorsintegrated with sustainable orchard cultural techniques that lead to improved cropping, fruit set and/or fruit quality and aid in reducing pest pressures within the orchard environment.
Accomplishments: Worked with BASF Corp., Ag products Div. and colleagues at several state experiment stations to develop the plant bioregulator prohexadione-calcium, which was registered as Apogee? for use to control vegetative growth in apple. Was one of first in
Dr. Mark Brown, Entomologist, USDA-ARS, AFRS
Dr. D. Michael Glenn, Soil Scientist, USDA-ARS, AFRS
Dr. John Norelli, Plant Pathologist, USDA-ARS, AFRS
Dr. Thomas Tworkoski, Plant Physiologist, USDA-ARS, AFRS
4. Study the effect and interaction of temperature, shade, light, and whole tree gas exchange on flowering, fruiting, fruit drop, and growth in apple.
Background: Environmental factors play a significant role in the growth and productivity of apple trees. The mid-Atlantic fruit growing region presents a unique temperate climate and soil environment to examine physiological changes resulting from environmental factors and the ultimate effect on tree growth, productivity, and fruit quality. A better understanding of these processes and their effect(s) could lead to new cultural management techniques and increased production efficiency.
Goal: Under field conditions manipulate and monitor the orchard and/or canopy environment to gain a better understanding of key processes in apple tree physiology and annual cropping.
Approach: Young bearing apple trees in an established orchard will be shaded at specific intervals on a daily basis throughout the growing season and/or for specific periods of time after petal fall to determine the effect on growth, flowering, fruit set, fruit quality, yield, and carbon partitioning. Detailed records of light and temperature conditions within treated and control tree canopies will be collected and incorporated with growth, fruit set, and yield data for analysis in the Cornell Apple Tree Carbon Model. The effect of select thinning bioregulators will be closely monitored along with changes in shoot carbon levels. Field planted trees will be treated with supplemental lighting to determine the effect on carbon partitioning within the tree.
Accomplishments: Preliminary data has shown significant differences in tree response to constant (24 hours) vs partial (3 to 6 hours) shading and suggests that light at specific time periods during the day (morning) may have a more positive effect on growth and fruiting than at other time periods (afternoon).
Dr. D. Michael Glenn, Soil Scientist, USDA-ARS, AFRS
Developed technique and label recommendations for the control of rootsuckers and watersprout growth on apple trees using the bioregulators, NAA (Tre-Hold).
Conducted studies on nitrogen fertilization of apple that demonstrated the annual application of nitrogen fertilizers could be reduced without loss in productivity. Studies provided basis for new fertilizer recommendations that were incorporated by extension fruit specialists. Recommendations resulted in reduced N soil residues.
Conducted studies and provided data that played a significant role in developing the use of gibberellin sprays for the control of the "Stayman apple cracking" disorder.
Developed the first replicated data to support recommendations for pruning peach trees injured by low winter temperatures.
The first to demonstrate the effectiveness of plastic reflective groundcovers for improving red color on selected apple cultivars in the mid-Atlantic region. These materials are now commercially available for fruit growers in the eastern
Together with a colleague was the first to recognize and characterize a novel disorder in nectarine named nectarine pox. Based on our research, nectarine growers can take steps to reduce the incidence of the disorder.
Together with a colleague at AFRS demonstrated the potential for mechanically harvesting semi-dwarf free-standing apple trees and identified limitations.