Interactions among cereal cyst nematode Heterodera filipjevi, dryland crown rot Fusarium culmorum, and drought on grain yield components and disease severity in bread wheat

Authors: AHMADI, MAHIN - University Of Shahrekord; MIRAKHORLI, NEDA - University Of Shahrekord; ERGINBAS-ORAKCI, GUL - International Maize & Wheat Improvement Center (CIMMYT); ANSARI, OMID - Ecofibre Ltd; BRAUN, HANS-JOACHIM - International Maize & Wheat Improvement Center (CIMMYT); Paulitz, Timothy; DABABAT, ABDELFATTAH - International Maize & Wheat Improvement Center (CIMMYT)

Submitted to: Canadian Journal of Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/29/2021
Publication Date: 5/4/2022
Citation: Ahmadi, M., Mirakhorli, N., Erginbas-Orakci, G., Ansari, O., Braun, H., Paulitz, T.C., Dababat, A. 2022. Interactions among cereal cyst nematode Heterodera filipjevi, dryland crown rot Fusarium culmorum, and drought on grain yield components and disease severity in bread wheat. Canadian Journal of Plant Pathology. 44(3):415-431. https://doi.org/10.1080/07060661.2021.2013947.
DOI: https://doi.org/10.1080/07060661.2021.2013947

Interpretive Summary: A study was undertaken to determine the effect of cereal cyst nematode (Heterodera filipjevi), Fusarium crown rot, and drought. What is unique is that they tested all combinations in a factorial experiment to look at interactions, and tested a range of accessions of wheat. Fusarium crown rot was exacerbated by drought stress, but the number of cysts of Heterodera was reduced when co-inoculated with Fusarium. Yield components were significantly reduced by each of the single stresses and losses were greater when plants were exposed to double or triple stresses. In conclusion, water stress accelerates the damage caused by both soil borne pathogens. Planting drought-resistant varieties would be an ideal solution to reduce losses by these diseases.

Technical Abstract: The cereal cyst nematode of the genus Heterodera and the crown rot caused by Fusarium species are considered two significant soil borne diseases limiting cereal production and their yield potential. The losses increase when both diseases coexist in the same field especially under water stress conditions. The main objective of this study was to investigate the interaction among Heterodera filipjevi, Fusarium culmorum, and drought on a set of wheat germplasm with differing levels of resistance/tolerance to both diseases as well as drought. The obtained results showed that plant emergence was significantly reduced (56% seedling death) when seeds were planted under a water stress environment where both F. culmorum and H. filipjevi were present. Crown rot assessment showed that damage of F. culmorum under the water stress condition was greater compared to the Fusarium inoculation alone. Interestingly, the results indicated that the number of cysts fell significantly when H. filipjevi was co-inoculated with F. culmorum, revealing antagonistic interaction between the two diseases. The highest number of nematode cysts was found on the susceptible accession ‘Seri’ under water stress conditions. Water stress caused significant reduction in plant height while F. culmorum inoculation did not, unless combined with water stress. Yield components were significantly reduced by each of the single stresses and losses were greater when plants were exposed to double or triple stresses. Water stress and F. culmorum inoculation caused significant reduction in spike weight and seeds per spike. Chlorophyll content of wheat leaves was negatively affected by water stress and inoculation by both pathogens. In conclusion, water stress accelerates the damage caused by both soil borne pathogens. Planting drought-resistant varieties would be an ideal solution to reduce losses by these diseases.