|ELLIS, MARGARET - Fresno State University|
|MADDOX, ANN - Fresno State University|
|GARCIA, JORGE - Fresno State University|
|HUTMACHER, ROBERT - University Of California, Davis|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 12/18/2022
Publication Date: 1/10/2023
Citation: Ellis, M.L., Maddox, A.M., Garcia, J., Wallis, C.M., Hutmacher, R.B., Ulloa, M. 2023. Evaluation of the Fungal Interaction between Fusarium Oxysporum f. Sp. Vasinfectum Race 4 and Rhizoctonia Solani on Disease Development in Pima and Upland Cotton. Meeting Abstract. NA.
Technical Abstract: Fusarium oxysporum f. sp. vasinfectum race 4 (FOV4) and Rhizoctonia solani are important soilborne pathogens of cotton. The aim of this study was to evaluate the interaction of both pathogens with varieties Pima and Upland cotton that differ in FOV4 susceptibility/resistance. A greenhouse study was used to evaluate the interaction of these two fungal pathogens. Briefly, seeds were planted into pots with a layer of infested-oat seed inoculum with the following treatments: FOV4 alone, R. solani alone, co-inoculation with both pathogens, and non-inoculated oats were used as a control. At two weeks, one of five replications was collected for the measurement of stress/defense related compounds associated with disease development. Data from the other four replications for stand counts, shoot and root weight, foliar, vascular, and root rot data were collected at five weeks after inoculation. The experiment was replicated for a total of two times. Results showed that significantly more disease development in the co-inoculation and R. solani treatments occurred for stand counts, shoot weight, and root rot data (P<0.05). Additionally, symptoms increased in the co-inoculation treatment when compared to the FOV4 treatment (P<0.05) for FOV4 foliar and vascular data. Disease development was most severe in the FOV4 susceptible varieties. Disease also increased in the more resistant FOV4 varieties when co-inoculated with both pathogens. These results provide evidence that R. solani may compromise FOV resistance in Pima and Upland cotton plants. Additionally, the measurements of phenolic compounds, volatile compounds, sugar content, and amino acid levels was completed and we hope that this will further provide evidence of the FOV4 and R. solani interaction and the response in the plant host when co-infected with both pathogens.