Location: Forage Seed and Cereal Research Unit
Project Number: 2072-21500-001-021-I
Project Type: Interagency Reimbursable Agreement
Start Date: Feb 15, 2026
End Date: Feb 14, 2028
Objective:
The overall goal of this grant proposal is to understand heat and drought stress tolerance in Lolium perenne (perennial ryegrass).
Objective 1: Identify genetic loci controlling heat and drought tolerance in perennial ryegrass.
Objective 2: Evaluate post-germination recovery potential of perennial ryegrass following heat and drought stress.
Approach:
Cool-season grasses like perennial ryegrass have value as forage, turf, and cover. However, seed production and end-use of these grasses are currently geographically limited by perennial ryegrass’s level of tolerance for abiotic stresses like extreme heat and drought. This limitation may be exacerbated by changing climate. Improving tolerance to these stresses in perennial ryegrass would be accelerated by better understanding of the genetics of heat and drought tolerance. ARS scientists will perform a genome-wide association study (GWAS) by growing plants from 200 perennial ryegrass collections from USDA NPGS under irrigated and non-irrigated conditions in Corvallis, OR (milder summers) and Hermiston, OR (hotter summers). Plant growth, survival, and seed production traits will be monitored for two seasons, and the plants will be genotyped using genotyping-by-sequencing (GBS). Genome-wide association will show which genetic loci are associated with specific heat and drought tolerance traits. In addition, plants from the same USDA NPGS perennial ryegrass collections will be germinated in the greenhouse, immediately subjected to heat or drought stress, and then allowed to recover. Data from this experiment will show how well these collections can survive brief extreme weather events during a critical early period for grass stand development.