The effect of CO2 and temperature on Fusarium crown rot incidence, severity, pathogen colonisation, toxigenic potential and host resistance in a selection of wheat germplasm

Abstract

Rising atmospheric CO 2 may impact on host and pathogen interactions to the benefit or detriment of crop productivity. The wheat disease Fusarium crown rot (FCR), caused by the pathogen Fusarium pseudograminearum, is predicted to increase in incidence with rising CO 2 due to changes in wheat resistance. Fusarium spp.regularly reduce the quantity and quality of wheat yields around the globe. Reported here are a collection of studies which show FCR incidence and susceptibility in wheat plants is likely to increase in a future with higher atmospheric [CO 2 FCR resistance, susceptibility and crown rot induced crop losses through lower grain weight, were dependent on host genotype. On average genotype L2-120, 2-49, and Sunco showed the highest resistance to FCR while Tamaroi, Janz and Wyalkatchem showed the lowest resistance. Overall, increasing atmospheric [CO 2 ] is likely to lead to a greater build-up of FCR inoculum in wheat, encouraging an increased disease incidence in susceptible varieties of wheat. With greater FCR incidence and subsequent changes to toxin production is likely to boost DON in plant stems. From this research it is likely that e[CO 2 ] will lower crop productivity where FCR is present and negatively impact on the quantity and quality of future crop yields. The consequences of these changes may be mitigated through crop breeding programs with the purpose of developing wheat varieties with improved FCR resistance, FCR tolerance and the ability to detoxify DON mycotoxin.iv