Evaluation location: Kentucky, United States
Part of SAC HEMP PATHOLOGY, UKY GERMPLASM TRIAL, FUSARIUM HEAD BLIGHT, 2024 USDA-PGRU/UKY CA (https://www.ars.usda.gov/research/project/?accnNo=445654). Trial in Lexington Kentucky. Trial Planting July 11, 2024, with last rating Sept 25, 2024. Hurricane Sept 27, plants fell over and were not ratable. Note, disease severity increased dramatically after the hurricane (6” rain in two days), but plants were broken and fallen into adjacent plots. General weather 2024: excessive heat and drought. July heat index max 104.5, mean 92.2; high temperature max 94.7, mean 87.4; high RH mean 92.8%, Precip 2.5 inch. August heat index max 101.5, mean 89.5; high temperature max 97.5, mean 85.8; high RH mean 94.1%; Precip 3.3 inch. September head index max 95.5, mean 81.0; high temperature max 91.0, mean 80.1; high RH mean 92.5%; Precipitation 6.2 inch.
FHB Disease Severity:
Plot 144 disease emergence Aug 28, final ratings 20-40% severity
Plot 145 disease emergence Aug 28, final ratings 0-30% severity
Plot 163 disease emergence Aug 28, final ratings 20% severity
Plot 204 disease emergence Aug 7, final ratings 20-30% severity
Plot 219 disease emergence Sept 11, final ratings 10-20% severity
Plot 254 disease emergence Aug 14, final ratings 0-30% severity
Plot 323 disease emergence Aug 28, final ratings 20-30% severity
Plot 353 disease emergence Sept 11, final ratings 10-20% severity
Plog 385 disease emergence Sept 25, final ratings 0-10% severity
*all other plots, disease 0% incidence, 0% severity
To assess accessions for resistance to Fusarium head blight, seed of each accession will be sown in 144-cell trays and grown for 3 to 4 weeks before transplanting into the field at the University of Kentucky North Farm Complex near Lexington, KY. Transplants will be planted into conventionally tilled soil using the production model typically practiced for burley tobacco production (no raised beds and no plastic) in rows spaced 1.07 m apart with 0.3 m between plants within the row. Drip irrigation will be provided as needed. Accessions will be planted in the field in a randomized complete block design with 10 plants per plot and 3 replications. Previous research at this location has shown that Fusarium head blight is endemic in this area so we will use natural inoculum to assess resistance. Wheat will be planted in early spring to increase inoculum in the area, and artificial inoculations will supplement natural infections, as needed. Fusarium disease will be assessed for incidence and severity using a quantitative rating scale (Gauthier, unpublished). Because accessions are expected to have varied and inconsistent maturity, ratings will take place every two weeks beginning at flowering. Disease assessments and plant development stage will be recorded. The area under the disease progress curve (AUPDC) will be calculated and means separated using Tukey’s HSD. All statistics will be performed using R statistical packages. Samples of plants with delayed disease development or signs of tolerance to FHB will be sent to the USDA PGRU greenhouses for genotyping and hybridizations.