Pomology, plant physiology, apple, cherry, peach, plum, irrigation, plant bioregulators, chemical thinning, rootstocks, orchard systems, tree fruit nutrition, cultivars, soil management, cherry cracking

Research Interests:

SIMCOE - APPLES
The value of the Ontario apple industry, estimated to be valued at approximately $400 million, is the predominant fruit crop in Ontario. The wide diversity of growing regions, cultivars, rootstocks, and soil types which influence the cultural and production of this crop create a unique and challenging blend of research needs to help solve the apple industry's short and long-term problems. The Horticultural Experiment Station, Simcoe, has 15 hectares of orchard dedicated to apple research. Research and extension interests of this project are directed toward gaining and communicating a better understanding of apple tree physiology. Recognizing the factors that influence yield and fruit quality are one of its main thrust. Studies focus on the evaluation of new cultivars for suitability under Ontario's soil and climatic regime that can generate high market returns and/or develop niche markets and products. New cultivars that show resistance to pests and disease are being sought in order to reduce the amount of agri-chemicals and pesticide residues. Studies also focus on utilizing dwarfing Malus rootstocks and their influence on precocity, cropping efficiency, and tree vigour, and the performance of various cultivar/rootstock combinations in various intensive orchard production systems. Research on advanced horticultural technologies including new orchard training systems, advanced irrigation systems (such as sub-surface drip irrigation), and advances in the plant bio-substances such as gibberellins to regulate flowering and fruiting to minimize hand thinning, and prohexidione-calcium to reduce vegetative growth, are being actively pursued. Soil management studies to evaluate the benefits of soil amendments recycled from agricultural and industry sources on tree establishment, cropping, and ag-sustainability, and plant nutrition studies focusing on the improvement of fruit quality and yield are also an integral part of this research project. Our research endeavors are devoted to helping Ontario apple growers produce premium quality fruit consistently, competitively and profitably, using sustainable agricultural practices.

Project Objectives
Primary Goals:

1. To provide Ontario orchardists the technical information required to produce premium quality fruit consistently, competitively, and profitably using sustainable orchard practices.
2. To enhance our understanding of the physiological processing influencing tree growth, flowering, and fruit productivity.

Research Objectives:

1. Tree biology in relation to plant bioregulators (PBR) to regulate cropping, improve production efficiency and fruit quality.
2. Beneficial use of organic amendments and irrigation for reducing soil-borne disease and use of herbicides, improving fruit quality and plant health, minimizing soil groundwater contamination, and enhancing water conservation.
3. Quantify the performance of various rootstock/scion combinations under different orchard, environment and management systems.
4. Optimizing tree fruit mineral nutrition for enhanced fruit quality, tree growth, and with minimal consequence on the environment.
5. Identify adaptable tree fruit cultivars with a range of ripening dates useful for fresh market production.

VINELAND - CHERRIES, PEACHES, & PLUMS
The value of the Ontario tender fruit industry, estimated to be valued at approximately $100 million, and next to apples, is the most important tree fruit crop in Ontario. The wide diversity of tender fruit crops, cultivars, rootstocks, and soil types which influence peach, nectarine, cherry, and apricot production creates a unique and challenging blend of research needs to help solve the industry's short and long-term problems. Research and extension interests of this project are directed toward gaining and communicating a better understanding of the physiology processes affecting growth, yield and fruit quality. Research will focus on utilizing dwarfing precocious Prunus rootstocks and to determine their influence on cropping efficiency, tree longevity vigour, and fruit quality. New research on advanced horticultural technologies including new central leader and Fusetto (spindle) training systems, advanced irrigation and organic mulching systems, and plant bio-substances such as gibberellin, ethylene biosynthesis promoters and inhibitors to influence flowering and fruiting are being actively pursued. Our research endeavours are devoted to helping Ontario tender fruit growers the ability to produce premium quality fruit consistently, competitively and profitably, using sustainable agricultural practices.

Canadian tender fruit production is concentrated in Ontario (70%) and British Columbia (30%) with an annual production of 66, 550 metric tonnes and a five year average farm-gate value of nearly $59 million (Anonymous, 2002). Domestic production of peaches, plums and nectarines account for about 60%, 17% and 4%, respectively of the total Canadian supply of tender fruits. Imports of tender fruit, (mostly from the United States) however exceed domestic production by a ratio of 2:1; and have a marketed value of $188 million or 75% of the total market value of tender fruit sales in Canada. This deficit in market value (domestic value is 25% of the value of imports) and trade (32% of total consumption is produced domestically) indicates there is real potential for the domestic supply to offset imports when competing within similar production seasons.

Research Objectives

1. Fruit Tree Water Relations and the Physiology of Rain-Induced Cracking of Sweet Cherries
2. Research Based Evaluation of Peach Tree Forms
3. Tree physiological research leading toward better management practices for stone fruit orchards
4. Quantify the performance of various Prunus rootstock/scion combinations under different orchard, environment and management systems.
5. Fruit tree biology in relation to plant bioregulators (PBR) to regulate cropping, improve production efficiency and fruit quality

For further information please visit:
http://www.plant.uoguelph.ca/treefruit

Selected Publications:

Greene, D., R. Crassweller, C. Hampson, R. McNew, S. Miller, A. Azarenko, B. Barritt, L. Berkett, S. Brown, J. Clements, J. Cline, C. Embree, E. Fallahi, E. Garcia, G. Greene, T. Lindstrom, I. Merwin, J.D. Obermiller, D. Rosenburgerm and M. Stasiak. Multidisciplinary Evaluation of new apple cultivars: The NE-183 Regional Project 1999 Planting. (2007). Journal of the American Pomological Society 61(2):78-83.

Crassweller, R., R. McNew, D. Greene, S. Miller, A. Azarenko, B. Barritt, L. Berkett, S. Brown, J. Clements, J. Cline, W. Cowgill, C. Embree, E. Fallahi, B. Fallahi, E. Garcia, G. Greene, T. Lindstrom, I. Merwin, J. Obermiller, D. Rosenburger and M. Stasiak. I. Growth and Yield Characteristics of Apple Cultivars in the 1999 NE-183 Regional Project Planting. (2007). Journal of the American Pomological Society 61(2):84-96.

Miller, S., R. McNew, R. Crassweller, D. Greene, C. Hampson, A. Azarenko, L. Berkett, W. Cowgill, E. Garcia, T. Lindstrom, M. Stasiak, J. Cline, E. Fallahi, and G. Greene II. (2007). Performance of Apple Cultivars in the 1999 NE-183 Regional Project Planting: II. Fruit Quality Characteristics. Fruit Varieties Journal 61(2):97-114.

Cline, J.A. and M.C.T Trought. (2007). Effect of Gibberellic Acid (GA3) on Fruit Cracking and Quality of 'Bing' and 'Sam' Sweet Cherries. Canadian Journal of Plant Science (Manuscript Number P06-132) Accepted for publication Jan 4, 2007 (In Press)

Robinston, T., L. Anderson, W. Autio, B.H. Barritt, J.A. Cline, R.M. Crassweller, W. Cowgill, C. Embree, D. C. Ferree, E. Garcia, G.M. Greene, C. Hampson, K. Kosola, M. Parker, R. Perry, T. Roper, and M. Warmund. (2007). A multi-comparison of Geneva 16, Geneva 41, and M.9 apple rootstocks across North America. Acta Horticulturae (In Press)

Robinston, T., L. Anderson, W. Autio, B.H. Barritt, J.A. Cline, R.M. Crassweller, W. Cowgill, C. Embree, D. C. Ferree, E. Garcia, G.M. Greene, C. Hampson, K. Kosola, M. Parker, R. Perry, T. Roper, and M. Warmund. (2007). A multi-comparison of Geneva 16, Geneva 41, and M.9 apple rootstocks across North America. Acta Horticulturae (in press)

Autio, W.R., J.L. Anderson, B.H. Barritt, J.A. Cline, R.M. Crassweller, C.G. Embree, D.C. Ferree, M.E. Garcia, G.M. Greene, E.E. Hoover, S. Johnson, K. Kosola, J. Masabni, M.L. Parker, R.L. Perry, G.L. Reighard, T.L. Robinson, and M. Warmund. (2007). Early Performance of ‘Fuji’ and ‘McIntosh’ Apple Trees on Several Semidwarf Rootstocks in the 1999 NC-140 Rootstock Trial. Acta Horticulturae 732 p. 127-133.

Autio, W.R., J.L. Anderson, B.H. Barritt, J.A. Cline, R.M. Crassweller, C.G. Embree, D.C. Ferree, M.E. Garcia, G.M. Greene, E.E. Hoover, S. Johnson, K. Kosola, J. Masabni, M.L. Parker, R.L. Perry, G.L. Reighard, T.L. Robinson, and M. Warmund. (2007). Early Performance of ‘Fuji’ and ‘McIntosh’ Apple Trees on Several Dwarf Rootstocks in the 1999 NC-140 Rootstock Trial. Acta Horticulturae 732 p. 119-125.

For a complete listing of Dr. Cline's publications, please visit the Pomology website.