|CHAGOYA, JENNIFER - Texas A&M Agrilife|
|WHEELER, TERRY - Texas A&M Agrilife|
|ARCE, HEATHER - Texas A&M Agrilife|
|ARCE, JOEL - Texas A&M Agrilife|
|MONCLOVA-SANTANA, CECILIA - Texas A&M Agrilife|
Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Abstract Only
Publication Acceptance Date: 1/6/2022
Publication Date: 5/30/2022
Citation: Chagoya, J., Ulloa, M., Wheeler, T.A., Arce, H., Arce, J., Monclova-Santana, C. 2022. Fusarium oxysporum f. sp. vasinfectum race 4 soil inoculum quantification in response to resistant and susceptible cotton cultivars. National Cotton Council Beltwide Cotton Conference. Paper No. 495.
Technical Abstract: Fusarium oxysporum f. sp. vasinfectum race 4 (FOV4) is a virulent soilborne plant pathogen that causes devastating losses in cotton. More research is needed to understand the soil inoculum dynamics and dispersal for the management of this pathogen. The objective of this research is to evaluate the use of host plant resistance for the management of FOV4 by quantifying pathogen reproduction and plant infection on susceptible and resistant or tolerant cultivar hosts using a molecular quantitative PCR assay. Two FOV4 field trials were planted in El Paso, Texas, in 2020 and 2021, each consisting of both Pima and Upland cultivars varying in response to FOV4. Plant survival, root vascular necrosis, and yield data were collected in the field. Soil samples were collected at planting, midseason, and harvest for DNA extraction and quantification of FOV4 by real-time PCR using FOV4-specific primers. Resistant cultivars had higher survival, lower root necrosis, and higher yield than susceptible cultivars in both trials and years. Significant differences among cultivars were observed for FOV4 quantity at midseason and harvest, with DP 340 Pima, Pima 3-79, Pima S-7, PHY 72 Acala, and DP 357 Pima having significantly greater FOV4 quantities than other cultivars. The above cultivars are known to have different levels of susceptibility when planted in infested FOV4. Resistant Upland PSS-U77 (recently released as PSSJ-FRU14) had the highest survival and lowest root necrosis and was among the lowest FOV4 quantities observed. Field measures were correlated with FOV4 quantity at different time points, showing that survival and yield decreased, and root necrosis increased as FOV4 quantity increased. This research shows that planting resistant cultivars prevented an increase of FOV4 in the soil during the growing season, indicating that host plant resistance is an effective strategy to manage FOV4 populations in soils.