Location: Forage Seed and Cereal Research Unit
Project Number: 2072-21500-001-001-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Aug 1, 2019
End Date: Sep 30, 2022
Objective:
The objective of this project is to develop new techniques to reduce or eliminate herbicide resistant weed seeds in cool-season grasses grown in Oregon.
Approach:
Development of herbicide bioassay procedures: Seeds of annual and Italian ryegrass will be subjected to dose response assays with commonly used herbicides in Oregon to obtain herbicide susceptibility thresholds values for weeds and crops.
Marker development for herbicide resistance: Molecular markers will be developed to identify commonly occurring types of herbicide resistance in Italian ryegrass. We will utilize a RAD-seq dataset from 192 Italian ryegrass individuals and annual ryegrass to identify indels/SNPs/structural variants that could be used to distinguish the weed species from the crop. Upon identification of potential markers, Kompetitive Allele Specific PCR (KASP) assays will be developed for the rapid identification of weed seed contamination in commercial seed lots.
Development of precision chemical management for controlling weeds in the field: Data from grid-sampling will be used to create maps of the within-field distribution of roughstalk bluegrass. Maps of weed distribution will be created and used to treat roughstalk bluegrass with a marginally-selective herbicide (glufosinate, 0.375 lbs/A). The data collected by spray monitors and yield monitors will be analyzed with spatially-weighted regression analysis to determine if there is a significant decrease in yield where precision-applied glufosinate is sprayed. These relationships (impact of glufosinate on yield and impact of weed density on yield) will be used to create decision support tools that allow growers to determine if spraying marginally-selective herbicides will improve yields.
