Effects of crown rot severity caused by Fusarium culmorum on agronomic performance of wheat genotypes.

Global climate change, characterized by extreme temperatures, drought, and irregular precipitation, has intensified environmental stress conditions. In Middle Anatolia, harsh ecological conditions and monoculture-based agricultural practices further increase the incidence and severity of fungal diseases. The study aimed to determine the effects of crown rot disease on the grain yield and some agronomic characteristics of bread wheat cultivars. The experiments were conducted during the 2024-25 growing season in Yozgat and Yerköy locations, using 35 registered bread wheat cultivars, in a randomized block design and with three replications. Fusarium culmorum inoculation was applied twice under field and pot conditions; first on the seeds just before planting, second stem elongation stage using the grain colonization method. Bread wheat cultivars showed disease severity ranging from 6.3 to 54.2% under field conditions and 16.4–82.7% under pot conditions. Under field conditions, Fusarium culmorum inoculation caused 9.3% loss in plant numbers in the plot during the post-emergence period and 11.3% loss during the post-winter period, as well as an average reduction of 6.2% in plant height, 5.3% in thousand-kernel weight, and 17.9% in grain yield. In the pot experiment, Fusarium culmorum inoculation resulted decrease in flag leaf chlorophyll content (5.4%), plant height (5.8%), and grain yield (7.8%). The total physiological stress caused by fungal inoculation on the wheat cultivars studied was assessed by spike yield. A standardized yield value was then calculated for all spikes using a formula developed. Based on the standardized yield, 77.8% and 42.1% yield reduction was noted in inoculated spikes under field and pot conditions, respectively. These results indicate that crown rot disease poses a serious risk to wheat production. Therefore, developing strategies to prevent the disease and the losses it causes, especially the breeding of resistant varieties, is of great importance.