Targeted Breeding of Fusarium Wilt Resistance in Spinach Using a Hydroponic Selection Assay
Lynch , Ryan T
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Fusarium wilt of spinach (Fusarium oxysporum f. sp. spinaciae) is an economically important fungal pathogen endemic to nearly all global spinach production regions, posing a significant threat to both vegetable and seed crop yields. Infected fields often require a decade plus of crop rotation away from spinach before new crop can safely be re-introduced. Soil amendments and soil bioassay risk assessments can help mitigate crop losses, but high-level genetic resistance in commercial cultivars is urgently needed to preserve the viability of diminishing production acreage. Soil based screening assays are the current standard for resistance breeding efforts but lack a high degree of specificity for targeting resistance genes due to the difficulty of successful selection and inbreeding of resistant germplasm. A hydroponic assay was successfully developed that produced significantly different responses in resistant and susceptible check lines that were comparable to traditional soil assay results. Resistant selections from segregating F2 lines taken from the hydroponic assay were successfully inbred through self-pollination to produce F3 progeny lines. Hydroponic screening of F3 lines found a significant increase in resistance levels to Fusarium oxysporum f. sp. spinaciae in two of the three progenies. Overall, the results provide a promising proof of concept for a hydroponic selection assay that offers the potential for increasing breeding efficiency and genetic gain for Fusarium oxysporum f. sp. spinaciae resistance.
CC0 1.0 Universal, 2023