PROJECT RESULTS

Novel Methods for Managing Fusarium Head Blight (FHB)-Infested Wheat Seed

Applicant: 

Dr. Jeannie Gilbert

Cereal Research Centre

Agriculture and Agri-Food Canada

Winnipeg, Manitoba  R3T 2M9  Canada

Table of Contents:

• Background and Objectives
• Procedure and Project Activities
• Results and Discussion
• Conclusions

ARDI Project:

#01-491

Total Approved:

$19,500

Date Approved:

January 31, 2003

Project Status:

Completed March, 2004

Background and Objectives:

The progress in registering fusarium head blight (FHB)-resistant wheat has been slow and measures for disease management have assumed an important role.  Among these, reduced survival, or eradication of the fungus from infested seed, and improved agronomic performance, have become important issues in light of recent measures to restrict movement of infested seed into western Saskatchewan and Alberta.  Several novel methods have been, and continue to be, tested to identify economical ways to control seed-borne FHB.

Procedure and Project Activities:

• Seed was treated with 9 different heat treatments ranging from 30°C to 90°C for 5 days.

• Seed was treated with two concentrations of acetic acid.

• Gustafson treated infested seed with 3 Raxil products: Raxil, Raxil + Thiram, and Raxil  JAU.

Germination and levels of F. graminearum were assessed before and after treatment.  Plots, 7 rows wide and 6 m in length, were seeded in a complete randomized block design with 4 replicates at Glenlea, Manitoba on May 29, 2003.  Assessments included emergence at 2 weeks on June 13, 2003.  Heading, height, and maturity were taken during July and August.  After harvest on August 27, yield, thousand kernel weight (TKW), and hectoliter weight were measured.

Results and Discussion:

Heat Treatments

Field emergence was very low after heat treatment at 90°C and the analysis was therefore restricted to the other treatments.  In 2003, anomalous results with two treatments suggest that there was a mechanical error with the ovens (Table 1).  The extremely low field emergence indicated a problem with treatments of Fusarium seed for 10 and 12 days at 70° C (Table 1), and resulted in significant differences for all variables in all treatments (Table 2).  When treatments for 10 and 12 days at 70° C were removed from the analysis, mean squares for emergence were the only values showing significant differences among treatments (Table 3).  These results were similar to those obtained in the first year of tests in 2002.

Table 1.  Effects of Heat Treatments on Emergence, Yield, Thousand Kernel Weight (TKW), Hectolitre Weight, and Height of Fusarium-Free and Fusarium-Infested Seed of Glenlea Wheat - 2003. 

^Z Seed treated at 38° C for 2 days before treatment.

^y Values in columns followed by the same, or no letter, are not significantly different at P  0.05.

Table 2.  Mean Squares from Analysis of Variance from Full Data Set in 2003.

** P # 0.0001, ^z Thousand kernel weight.

Table 3.  Mean Squares from Analysis of Variance in 2003 Excluding Treatments for 10 and 12 Days at 70° C. 

** P # 0.0001, ^z Thousand kernel weight.

Acetic Acid and Raxil-Based Fungicides

Treatment with acetic acid vapour at 0.8 ml resulted in poor germination and yield in both Fusarium-free and Fusarium-infested seed (Table 4).  When this treatment was removed from the analysis there were no significant differences among the remaining treatments.

Table 4.  Effects of Acetic Acid and Fungicide Treatments on Emergence, Yield, Thousand Kernel Weight (TKW), Hectolitre Weight, and Height of Fusarium-Free and Fusarium-Infested Seed of Glenlea Wheat - 2003. 

Values followed by the same letter are significantly different according to Tukey grouping at P#0.05.

Germination and Levels of Fusarium Graminearum Surviving Seed Treatments

Germination of treatments of Fusarium-free seed after 70°C for 10 and 12 days was poor, similar to field emergence, and again reflected a probable problem with the oven (Table 5).  There was also indication that there was contamination with seed treated at 70°C for 10 and 12 days with a pre-heat treatment of 2 days at 38°C as F. graminearum was found associated with both Fusarium-free and -infested  treated seed.  The experiment was repeated with remnant seed from the heat treatments (Experiment 2).  No F. graminearum survived the 70°C treatments.  The lower levels of F. graminearum on infected seed in Experiment 2 compared to Experiment 1 is likely because the seed after treatment had been exposed to room temperature for 4 months.  Under such conditions F. graminearum loses viability (Gilbert et al. 1997).

Acetic acid and fungicide treatments did not impair germination, except for acetic acid at a 0.8 ml concentration (Table 6).  However, only Raxil JAU eradicated the fungus from the seed.  The amount of seed available for these tests was small, and the experiments should be repeated to confirm the findings.

Table 5.  Effects of Heat Treatments on Germination of, and Survival of Fusarium graminearum (F.g.) in Fusarium-Free and Fusarium-Infested Seed of Glenlea Wheat - 2003.