Evaluation of Pea Accessions Differing in Flower and Seed Coat Pigmentation for Resistance to Fusarium avenaceum Root Rot

Abstract

Pea production across the world is significantly limited by root rot disease, which is caused by many fungal and oomycetes pathogens. In Canada, Fusarium avenaceum is the most devastating pathogen of the Fusarium root rot complex of pea. Host genetic resistance is the most effective control method for this disease. Evaluation of global pea accessions and Canadian varieties for F. avenaceum root rot resistance has not been reported to date. This study evaluated 20 pea accessions of different market classes with pigmented or nonpigmented seed coats and flowers for F. avenaceum resistance under controlled conditions. The pea accessions CDC Acer, CDC Vienna, PBA OURA, Morgan, CDC Blazer, CDC Dakota, and PI 280609, which have pigmented flowers and seed coats, were identified as resistant or partially resistant to F. avenaceum. This was based on their root rot severity scores and ability to tolerate F. avenaceum infection without significant (p > 0.05) reductions in plant height, shoot dry weight, and root dry weight. Among the varieties with nonpigmented flowers and seed coats, only Cameor showed partial resistance to F. avenaceum when challenged with reduced conidial concentration. Root dry weight (R = −0.86), plant height (R = −0.82), and shoot dry weight (R = −0.78) had a strong negative correlation (p < 0.001) with disease severity, suggesting that F. avenaceum root rot can negatively impact the growth and development of pea seedlings. F. avenaceum resistance identified in this study can be utilized to study the molecular basis of the resistance and develop disease-resistant varieties. While our findings suggest a relationship between pigmentation and F. avenaceum resistance, future research with a larger, more diverse panel is warranted to validate these initial results.