John T.A. Proctor

John Proctor
College Professor Emeritus



Bachelor's University of Reading;
M.Sc. Cornell University;
Ph.D. Cornell University



Perennial crops, assimilate partitioning, photosynthesis, phytohormones

My research consists of development of integrated sustainable production systems for perennial horticultural crops such as ginseng and fruit. The emphasis in these studies has been on microclimate and leaf and whole plant photosynthesis, respiration, assimilate partitioning, exogenous and endogenous phytohormones. Specific studies with ginseng include seed management strategies to optimize seed stratification and germination, tissue culture, somatic embryogenesis and ginsenoside analysis.

North American ginseng is grown extensively in Ontario and sold to markets worldwide for its medicinal and therapeutic properties. The estimated 2000 value of the cultivated crop in Ontario was $70 million. The crop requires a 4-year time period to harvest and presents unique management challenges. There are several inherent problems during the production of ginseng plants: 1) A high degree of genetic variability leads to a range in phenotypic traits, including root quality, size and ginsenoside levels; 2) Increased cultivation has led to a high incidence of foliar and root diseases that reduce crop yield and quality, and for which there are few control options; 3) The extended reproductive cycle of the plant (3-4 years) has discouraged efforts at crop improvement and cultivar development through breeding; 4) The prolonged constitutive dormancy period for seed germination (12-18 months) and low seed germination rates (50-60%) make plant establishment problematic. My research uses many techniques in the plant sciences to enhance the potential of ginseng production with the long-term goals of overcoming the above problems. I am working to achieve superior root quality, vigorous plant growth, high levels of ginsenosides, and reduce disease incidence.


Relevant Links:

Selected Publications:

Proctor, J.T.A., D. Louttit and J.M. Follett. (2001). Controlled temperature, above-ground stratification of North American ginseng seed. HortTechnology 11: 100-103.

Wang, X., J.T.A. Proctor, S. KrishnaRaj, P.K. Saxena and J.A. Sullivan. (1999). Rapid somatic embryogenesis and plant regeneration in American ginseng: effects of auxins and explants. J. Ginseng Res. 23: 148-163.

Percival, D.C., J.T.A. Proctor and J.P. Privé. (1998). Gas exchange, stem water potential, and leaf orientation of Rubus idaeus L. are influenced by drought stress. J. Hort. Sci. and Biotechnology 73: 831-840.

Proctor, J.T.A. (1996). Ginseng: old crop, new directions. p. 565-577. In: J. Janick and J.E. Simon (eds.). Proc. 3rd New Crops Conf., Amer. Soc. Hort. Sci., Alexandria, VA.

Proctor, J.T.A., T. Slimmon and P.K. Saxena. (1996). Modulation of root growth and organogenesis in thidiazuron-treated ginseng (Panax quinquefolium L.). Plant Growth Regulation 20: 201-208.