Thesis
Cold season tolerance and prevalence of seedling blights in sweet corn in the Columbia Basin of Washington
Washington State University
Master of Science (MS), Washington State University
12/2020
DOI:
https://doi.org/10.7273/000004203
Handle:
https://hdl.handle.net/2376/125258
Abstract
Washington State is a major producer of sweet corn in the United States with ~36,400 ha planted in the semi-arid Columbia Basin annually. Cold spring soil conditions and soilborne pathogenic species of Fusarium, Pythium, and Rhizoctonia can cause significant losses. In 2018, conventional (n = 31) and organic (n = 16) sweet corn fields were surveyed in the Columbia Basin to assess the prevalence of seedling blights. Stand losses ranged from 3.3-47.5% (14.9 ± 10.9%, mean ± standard deviation) and the incidence of stunting ranged from 3.7-23.4% (10.1 ± 5.3%), demonstrating the opportunity to improve sweet corn production. Of 14 species identified from 350 Fusarium isolates obtained from stunted seedlings, F. oxysporum, F. verticillioides, F. solani, and F. equiseti were the most prevalent. Five species and anastomosis groups (AGs) were identified from 66 Rhizoctonia isolates, with R. solani AG 4 the most prevalent. Pythium ultimum was the most prevalent of four species identified from 63 Pythium isolates. Approximately 60% of the Pythium isolates were resistant to the fungicide mefenoxam at 10 and 100 ppm, which might account for some stand losses. Isolates of P. irregulare, P. ultimum, and P. sulcatum were highly virulent on the sweet corn cv. SuperSweet Jubilee, as were isolates of R. solani AG 4 and AG 2, and F. acuminatum, F. graminearum, F. fujikuroi, F. oxysporum, F. proliferatum, F. solani, and F. verticillioides. There was variation in virulence among isolates of a species. Seed germination and seedling vigor are impeded when sweet corn seed is planted in cold soils. Accessions from the sweet corn breeding association panel of the USDA National Institute of Food and Agriculture Specialty Crops Research Initiative Project No. 2018-51181-28419 were planted in the Columbia Basin in spring of each of 2019 and 2020 to screen for cold tolerance. In 2019, 24 of 182 lines tested had greater emergence and vigor than the processing sh2 hybrid GSS 3071. In 2020, 223 of 580 lines evaluated displayed better emergence and vigor than the processing sh2 hybrid GSS 3951. The trials demonstrated significant potential for improving cold tolerance in sweet corn cultivars.
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Details
- Title
- Cold season tolerance and prevalence of seedling blights in sweet corn in the Columbia Basin of Washington
- Creators
- Ryan Keith Solemslie
- Contributors
- Lindsey J du Toit (Advisor) - Washington State University, Plant Pathology, Department of
- Awarding Institution
- Washington State University
- Academic Unit
- Plant Pathology, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Identifiers
- 99900896437701842
- Language
- English
- Resource Type
- Thesis