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Steve Loewen

Processing Tomato Breeding
College Research Professor


B.Sc. (Agr.) Horticultural Science – University of Guelph
M.Sc. Horticultural Crop Breeding – University of Guelph

Research Interests:

In a general sense I am interested in variability in plants from the standpoints of increasing variability and managing variability. More specifically, my research efforts revolve around increasing genetic diversity in processing tomato breeding lines for Ontario tomato growers and processors. The theme of variability connects with the plant identification courses I teach since they focus on variability in ornamental plants, and recognizing and describing that variation.

Recent or current projects include:

  • Remediation strategies to address vine decline disease complex in processing tomatoes
  • Advancing the competitiveness of Ontario’s processing tomato sector by piloting innovative solutions to emerging root disease pressures causing vine decline
  • Enhancing the nutritional value of processing tomatoes using genes that dramatically increase lycopene and polyphenols
  • Increasing genetic diversity in processing tomatoes (Solanum lycopersicum) by releasing regionally adapted breeding lines using germplasm introgressed by V. Poysa based on S. arcanum, S. peruvianum, S. chilense, S. habrochaites, S. lycopersicoides and S. pimpinellifolium
  • Evaluation of modified mass selection as a breeding method to develop polygenic resistance to bacterial spot in processing tomatoes

Research Associates:

Richard Wright
Ridgetown Campus
Phone: 519-674-1500 x63659


I teach in the Horticulture Diploma program at Ridgetown Campus. Courses include:

Recent Publications and Reports:


2011 How do breeding lines get to my field rev 2.0 - The first video of two based on a presentation at Leamington Tomato Day, 2011

2011 How do seed companies get seed of our breeding lines - The second of two videos based on a presentation given at Leamington Tomato Day 2011

2007 Processing Tomato Cultivar Trials Research Report, 2007 - A summary of the results of the processing tomato cultivar trials conducted during the 2007 season.

2006 Processing Tomato Cultivar Trials Research Report, 2006 - A summary of the 2006 results of the multi-location cultivar trial.

View the complete list of reports by Steve Loewen on the reports page.

For potential partners:

Contract breeding, disease resistance screening and variety evaluation services are available. Custom seed increase of open-pollinated tomato cultivars for other research projects is available. Materials transfer agreements are developed through the Office of Research and accompany all germplasm releases. For more information, please email me.

Page reviewed 05/29/2018