Characterization of the Virulence and Yield Impact of Fusarium Species on Canola (Brassica napus)

Abstract

Multiple species of Fusarium can contribute to the development of root rot in canola (Brassica napus), making disease management difficult. We conducted field and greenhouse experiments to investigate the impacts of Fusarium avenaceum and Fusarium proliferatum, and the interaction between Fusarium oxysporum and F. proliferatum on root rot severity and canola yields. Inoculation with any of the three Fusarium spp. resulted in significant disease severity and reduced seedling emergence compared with non-inoculated controls, leading to yield reductions of up to 35%. Notably, there was a strong correlation (r = 0.93) between root rot severity at the seedling stage and at maturity. Regression analysis indicated a linear decline in seedling emergence with increasing disease severity. Furthermore, disease severity at maturity adversely affected the pod number per plant and the seed weight per plant, with both parameters ultimately approaching zero at a severity of 4.0 on a 0–4 scale. Co-inoculation with F. oxysporum and F. proliferatum induced more severe root rot than inoculation with each species on its own, suggesting synergistic interactions between these fungi. Knowledge of these interactions and the relative virulence of Fusarium spp. will contribute to the improved management of root rot in canola.

The Host Range of Fusarium proliferatum in Western Canada

“…Similarly, QTLs associated with resistance to Fusarium root rot have also been identified in peas [45,46], as has a partial resistance or tolerance to root rot in soybeans [42]. There are limited reports, however, of a resistance or an enhanced tolerance in faba beans [47], canola [29], lentils [48], or lupine [49]. Nonetheless, the milder severity of root rot caused by F. proliferatum observed on barley and wheat in this study suggests that cereal crops may be less favorable In an earlier study, barley demonstrated a yield tolerance to the Fusarium crown rot caused by Fusarium pseudograminearum [50], while wheat genotypes with tolerances to Pythium root rot have also been reported [51].…”

“…Briefly, a grain inoculum was mixed with a Promix PGX potting medium (Sun Gro Canada Inc., Seba Beach, AB, Canada) at grain inoculum-to-potting medium ratios of 1:300 (v:v) (0.33%, 'low inoculum' concentration) or 1:150 (v:v) (0.67%, 'high inoculum' concentration), corresponding to 3 × 10 4 or 6 × 10 4 colony-forming units (cfu) per g of potting medium, respectively. These inoculum levels were based on an earlier study [29]. Each host variety was sown in 473 mL cups (Uline, Toronto, ON, Canada) filled with 400 mL of the inoculated potting medium at a density of 10 seeds per cup and was maintained under greenhouse conditions at approximately 25 • C, with a 12 h photoperiod and supplemental light intensity ranging from 250 to 450 µmol/m 2 /s.…”

“…Among the most prevalent species of Fusarium, F. avenaceum has demonstrated aggressiveness on legumes, cereals, and canola [24,27,28]. Recently, F. proliferatum has been reported to cause severe reductions in the emergence and yield of canola under both field and controlled conditions [29]. To our knowledge, however, there are no reports on the host range of F. proliferatum or its impact on the plant germination or growth of other field crops in this region.…”

Plant growth–promoting rhizobacteria: Peribacillus frigoritolerans 2RO30 and Pseudomonas sivasensis 2RO45 for their effect on canola growth under controlled as well as natural conditions

“…Bacterial isolates were screened for inhibition against fungal pathogens: Alternaria alternata 783, Botrytis cinerea 873, Fusarium culmorum 2333, Fusarium oxysporum 872, Fusarium solani 25, Phytophthora cactorum 1925, and Phytophthora megasperma 404, which can affect canola plants ( Fernandez, 2007 ; Krasnow and Hausbeck, 2015 ; Al-Lami et al., 2019 ; Romero et al., 2008 ; Monnier et al., 2018 ; Ismaiel et al., 2021 ; Yu et al., 2023 ). Plant pathogenic fungi were obtained from the Plant Pathogenic Bank of the Institute of Plant Protection in Poznan (Poland).…”

Diversity and Pathogenicity of Fusarium Root Rot Fungi from Canola (Brassica napus) in Alberta, Canada

“…In Alberta and other provinces of western Canada, root rot represents an important constraint to canola (syn. oilseed rape; Brassica napus L.) production, causing yield losses of up to 35% [ 8 ]. This is a cause for concern, as canola contributes CAD 29.9 billion annually to the national economy [ 9 ], with the vast majority of production in western Canada.…”