Winter Cereal Reactions to Common Root Rot and Crown Rot Pathogens in the Field

Abstract

In Australia, Fusarium pseudograminearum and F. culmorum are the two main fungi causing crown rot, while Bipolaris sorokiniana is the causal agent of common root rot. Fusarium graminearum is typically linked with Fusarium head blight; however, it has been associated with crown rot in Australia and other parts of the world. This study investigated the reactions of single cultivars of barley, bread wheat, durum wheat, oat, and triticale to inoculation with strains of F. pseudograminearum, F. culmorum, F. graminearum and B. sorokiniana in field trials across two seasons. Fusarium pseudograminearum and F. culmorum caused greater visual discolouration than F. graminearum and B. sorokiniana on both stems and sub crown internodes of all hosts. Fusarum pseudograminearum caused the greatest reduction in plant dry weight across hosts in both years. Durum wheat (cv. Hyperno) barley (cv. Grimmett), bread wheat (cv. Livingston) and triticale (cv. Endeavour) observed significantly high levels of visual discolouration on stems when inoculated with F. pseudograminearum, while oat (cv. Genie) exhibited the least visual discolouration. Despite variation in the visual discolouration, the DNA of all pathogens were detected in all cultivars. This research further highlights the complicated nature of the pathogen × strain × cultivar × environment interaction, which remains a challenge in breeding for genetic resistance. The specific infection of each fungus and the host responses in these field trials improves our understanding of disease development and its importance in cropping systems.