Investigating Sustainable and Cost-Effective Strategies to Expand Production of Food Quality Winter Pea as a Viable Specialty Crop in the Palouse: Final Report

This project evaluated whether beneficial soil rhizobia can enhance growth and stress tolerance in winter pea, an emerging specialty crop in Washington’s Palouse region. Winter pea offers higher protein content, improved drought and heat tolerance, and strong market potential, but expansion is limited by pest and pathogen pressures, particularly pea aphids and pea enation mosaic virus (PEMV).

Greenhouse experiments compared multiple winter pea cultivars with and without rhizobia inoculation under aphid and virus stress. Rhizobia consistently increased shoot biomass and plant survival, though effects on root growth varied by experiment. Significant cultivar differences were identified in tolerance to PEMV, with Lynx, Dint, and Klondike showing greater resistance. Rhizobia reduced susceptibility in certain susceptible cultivars such as Melrose and MiCa. Molecular analyses demonstrated that PEMV suppressed key defense hormones, including jasmonic and salicylic acid pathways, helping clarify mechanisms underlying cultivar-specific responses.

Findings provide growers with evidence-based strategies for improving winter pea performance while potentially reducing reliance on synthetic fertilizers and insecticides.