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Dr. Steve Loewen


  • Ph.D. Plant Breeding and Genetics – University of Guelph
  • M.Sc. Horticultural Crop Breeding – University of Guelph
  • B.Sc. (Agr.) Horticultural Science – 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, some of my research efforts revolve around increasing genetic diversity in processing tomatoes for Ontario tomato growers and processors.

My interests extend to enhancing the nutritional value of processing tomatoes for consumers, both as a food and as an ingredient in other foods, by elevating levels of carotenoids, especially lycopene, and by increasing nutritional value even further by breeding tomatoes that produce elevated levels of anthocyanins. I have an ongoing interest in improving other fruit quality characteristics such as soluble solids, that impact production efficiency and competitiveness for Ontario tomato processors.

In addition to traits that contribute to high yield and high fruit quality, the breeding program I lead emphasizes field traits like early fruit maturity and the ability of ripe fruit to retain their quality. In a country like Canada, with a limited growing season, these kinds of characteristics help to start the harvest season sooner in the summer and can lengthen the harvest season later into the autumn.

Recent or Current Projects

  • Incorporating a core set of disease resistance genes across all regionally adapted breeding lines developed
  • Processing tomato cultivar trials, which include field performance, pilot plant peeling performance and fruit quality measurements
  • Screening processing tomato cultivars for field tolerance to thifensulfuron methyl (Pinnacle®)
  • Development of the early fruit colouring tomato phenotype for commercial use
  • Breeding for elevated natural tomato soluble solids (NTSS) levels
  • Enhancing the nutritional value of processing tomatoes using genes that dramatically increase lycopene and anthocyanins
  • Evaluating genomic selection as a tool to supplement phenotypic selection in processing tomatoes
  • Using genomics tools to foster innovation in Canada’s processing tomato industry
  • Piloting innovative solutions to emerging root disease pressures causing vine decline
  • 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. cheesmaniae, S. chilense, S. chmielewskii, S. corneliomulleri, S. galapagense, S. habrochaites, S. lycopersicoides, S. pennellii, S. peruvianum and S. pimpinellifolium
  • Grow-out and roguing of Canadian heirloom tomato varieties

Research Technicians

Satinder Chopra

519-674-1500 Ext. 63659

Potential Partners

Custom seed increase of open-pollinated tomato cultivars in support of other tomato research projects is available. Tomato fruit quality measurements can be part of collaboration in research projects.

Seed companies interested in evaluating our breeding lines for use as open-pollinated cultivars, for use as parents in F1 hybrid cultivars or for further breeding and development, can contact me to discuss your objectives. A range of different materials transfer agreements can be developed through the Research Innovation Office to accompany all germplasm releases. For more information, please contact me using the information above.

Refereed Publications

View the complete list of Dr. Steve Loewen’s scientific publications on Google Scholar.