|CHAGOYA, JENNIFER - Texas A&M Agrilife|
|MONCLOVA-SANTANA, CECILIA - Texas A&M Agrilife|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/26/2021
Publication Date: 3/23/2021
Citation: Chagoya, J., Monclova-Santana, C., Ulloa, M. 2021. Soil quantification of fusarium oxysporum f. sp. vasinfectum race 4 and infection response on cotton cultivars [abstract]. Conference on Soilborne Plant Pathogens. Washington State University. Session I -P03.
Technical Abstract: Fusarium oxysporum f. sp. vasinfectum race 4 (FOV4) adversely impacts cotton production causing plant wilt and death. FOV4 is an inoculum density-dependent disease, thus continual growing of susceptible host plants may lead to uneconomical production in infested fields. Two separate trials were planted in different areas of the same FOV4-infected field in El Paso, TX in 2020. Trial 1 consisted of four Pima (G. barbadense L.) and eight Upland (G. hirsutum L.) cultivars of known varying reactions to FOV4 planted in four replications. Trial 2 consisted of four cultivars (a resistant Pima, a susceptible Pima, a tolerant Upland, and a susceptible Upland) planted in sixteen replications. To evaluate plant survival and root vascular infection, stand counts were recorded at 20 and 55 days after planting (DAP), along with visual ratings of root necrosis at 55 and 162 DAP. Additionally, soil samples were collected at planting (0 DAP), 55 DAP, and 143 DAP for DNA extraction and quantification of FOV4 by quantitative real-time PCR. Differences were observed among genotypes for soil FOV4 quantity at 55 and 143 DAP in both trials, with known susceptible cultivars having greater quantities of FOV4 present in the soil. Significant correlations were observed between field measures (survival, necrosis, and yield) and FOV4 quantity at 55 and 143 DAP. Due to the increased replications in Trial 2, significant correlations were also observed between field measures and FOV4 quantity at planting. In the first year of this research, these two separate trials showed that planting of resistant Pima and Upland cultivars prevented an increase of FOV4 in the soil during the growing season. Additionally, results from this research confirmed that FOV4 field inoculum density affects disease progress during the growing season. This is the first study in which cultivar FOV4 infection response and FOV4 soil inoculum quantity has indicated that host plant resistance is effective to manage FOV4.