Interaction of root-lesion nematode (Pratylenchus thornei) and crown rot fungus (Fusarium culmorum) associated with spring wheat resistance under simulated field conditions

The root-lesion nematode, Pratylenchus thornei, and the crown rot fungus, Fusarium culmorum, cause tremendous damage to a wide range of grain crops, resulting in significant economic losses in the global yield production. The presence of both pathogens simultaneously in cereal fields puts more pressure on breeding programs, restricting new resistant cultivars to express their potential. This study investigated 150 spring wheat lines of the 18KASIB-CORE nursery for their host suitability to P. thornei and F. culmorum, inoculated singly or in combination. Forty-eight lines were resistant to P. thornei, while 16 lines were moderately resistant to F. culmorum. Among these, nine lines maintained their resistance reaction against the complex disease involving both pathogens, while only four lines provided resistance against individual and combined infestations. Infestation scenarios of both pathogens were monitored for each resistant variety and predicted using both reproduction factor and disease index. Pratylenchus thornei downgraded all resistant lines to F. culmorum, facilitating infestation and making their severity more pronounced (169% cumulative damage) with a negative impact on yield performance. These findings are useful for improving nematode x fungus resistance in wheat and selecting promising germplasm for breeding purposes against both diseases.

Automated summary

The root-lesion nematode and the crown rot fungus cause significant damage to grain crops and pose challenges to breeding programs. This study identified resistant wheat lines to both pathogens, providing valuable insights for improving resistance and selecting promising germplasm.