Stress Protection in Spring Canola
Date: January 1995
Term: 2 years
Status: Completed
Researchers: Dr. D. Hume, D.E. Dewar, and R.A. Fletcher, University of Guelph
SaskCanola Investment: n/a
Total Project Cost: n/a
Funding Partners: n/a
Project Summary
A group of compounds known as triazoles, which exhibit varying degrees of both plant growth regulating and fungicidal activity, have been shown to increase the hardiness of plants to many types of environmental stresses. Researchers at the University of Guelph conducted a two-year trial in 1992 and 1993 to determine if Paclobutrazol (PBZ) protected spring canola against environmental stress, and to assess rates and seed treatment formulations on different cultivars. Overall, the research showed that PBZ was a potent growth regulator when used as a seed treatment, and that slow release formulations of PBZ were unnecessary.
Increasing the efficiency of future agricultural production involves the ability of crop plants to withstand damage by environmental factors such as frost, drought, heat and atmospheric pollutants. A group of compounds known as triazoles, which exhibit varying degrees of both plant growth regulating and fungicidal activity, have been shown to increase the hardiness of plants to many types of environmental stresses, particularly in areas of drought stress.
Researchers at the University of Guelph launched a two-year project in 1992 and over the winter tested a number of triazoles for their ability to protect selected cultivars against heat and drought stress. Paclobutrazol (PBZ), which is a growth regulator and fungicide that also protects plants against stress, was selected. Field trials were conducted in 1993, with three objectives: to assess the effects of rates of PBZ applications and seed treatment formulations on growth and yield of spring canola; to determine cultivar responses to PBZ; and to determine if PBZ protected spring canola against environmental stress.
PBZ was tested in three field trials at Elora and Cambridge, Ontario as a seed treatment for spring canola. The trials involved four replications of two seed treatments, both regular (Bonsai formulation) and slow-release formulations, three cultivars, Global, Kristina and Stallion, and four rates of PBZ at 0, 12.5, 25 and 50 mg/ha (0, 1.25, 2.5 and 3.75 mg/kg active ingredient).
Research results showed that PBZ was a potent growth regulator when used as a seed treatment. PBZ increased yields in three of the six comparisons at rates from 6.25 to 12.5 mg/ha. Yield increases, when they occurred, averaged 9.2% across all three cultivars. Yield increases were 14.5% larger with the stress-susceptible, triazine-tolerant cultivar Stallion than with Global or Kristina. However, stands decreased significantly at the highest rate of application.
At Elora in 1993, PBZ also increased the seed oil concentration in Stallion by 45.6% as compared to 42.7% in the untreated control, decreased free fatty acids by 0.46% as compared to a 1.12% decrease in the untreated control, and increased meal glucosinolates. Quality parameters were unaffected at other locations and with other cultivars.
Overall, the results showed that low rates of PBZ seed treatment can protect against stress. The research also shows that seed treatment appears to be an effective way of delivering PBZ to the crop at rates low enough so that stand establishment was not impaired, and that slow release formulations of PBZ were unnecessary.