Pathogenicity of Asymptomatically Residing <i>Fusarium</i> Species in Non-Gramineous Plants and Weeds to Spring Wheat under Greenhouse Conditions

Abstract

Despite significant efforts in recent decades to combat Fusarium head blight (FHB), this disease remains one of the most important and widely studied diseases of wheat and other cereal plants. To date, studies have focused on small grain cereals as hostplants for these pathogens, but it was recently discovered that asymptomatic non-gramineous plants and weeds can serve as alternative sources of fungi associated with FHB. The aim of this study was to evaluate the pathogenicity of Fusarium avenaceum, F. culmorum, F. graminearum and F. sporotrichioides isolated from non-gramineous plants and weed species to spring wheat under greenhouse conditions. A total of 91 Fusarium isolates, including 45 from weeds and 46 from non-gramineous plants were floret inoculated at mid anthesis. The FHB incidence and severity (%) of inoculated heads and the area under the disease progress curve (AUDPC) were calculated. To determine yield losses, the weight of 1000 grains (TGW) was evaluated. Results of the research showed that FHB severity (%) values in Fusarium spp.-inoculated heads from non-gramineous plants varied from 9.3% to 69.6% and AUDPC values ranged from 161.5% to 1044.6%. TGW was most significantly reduced by the F. culmorum isolates BN26r and BN39fl from Brassica napus and isolates BV15.1l and BV142.1pe from Beta vulgaris (37%, 30%, 28.8% and 31.8% respectively, compared to the water control). In Fusarium-inoculated heads from weeds, FHB severity values ranged from 6.2% to 81.0% and AUDPC values varied from 134.2% to 1206.6%. TGW was most significantly decreased by CBP1401r isolate from Capsella bursa-pastoris (52%). The study results suggest that the pathogenicity of Fusarium species isolated from different hosts to wheat more strongly depends on the Fusarium species and strain than the hostplant. Under greenhouse conditions, F. culmorum strain groups obtained from weeds, non-gramineous plants and Triticum were more pathogenic to wheat than the water control and other Fusarium species.

Keywords

• asymptomatic alternative hosts
• Fusarium head blight
• grain yield losses