Identifying Bulb Fennel Cultivars Suitable for Production in the Northwest United States

摘要

Two studies were performed in Mount Vernon, WA, to identify bulb fennel (Foeniculum x vulgare) cultivars and seeding practices best suited for the region. The first study evaluated 13 cultivars (Bronze, Finale, Florence, Genesi, Idillio, Orazio, Orion, Perfection, Preludio, Solaris, Tauro, Tenace, and Zefa Fino) over the course of 2 years; during the second year, the additional main factor of the seeding date was included. The second study evaluated three bulb fennel cultivars (Finale, Tauro, and Zefa Fino), four seeding dates (17 May, 31 May, 14 June, and 28 June 2018), and two planting methods (direct and transplant). Results of the two studies demonstrated that 'Finale', 'Orazio', 'Preludio', 'Solaris', and 'Tenace' had the greatest bulb production rate and yield and good bulb quality that met marketability standards. 'Genesi', 'Orion', and 'Perfection' had good bulb production during only 1 of the 2 years, whereas 'Bronze', 'Florence', 'Idillio', and 'Zefa Fino' had very low bulb productivity both years due to bolting. 'Perfection' and 'Tauro' exhibited internal cracking both years (incidence rates of 9.5% and 12.8%, respectively). The first harvest was 94 to 112 days after seeding during the first study. Direct seeded bulb fennel required 32 fewer days to harvest than transplanted bulb fennel during the second study. The average bulb circumference was 28.1 cm, with little variation between studies. Bulb tenderness for both studies was 617 g-force, on average, and the soluble solids concentration of bulbs in both studies was 4.9%. Ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry based on 38 tentatively identified compounds demonstrated no difference in the phenolic content of bulb fennel due to the cultivar. In conclusion, bulb fennel cultivars well-suited for production in northwest Washington were identified and direct seeding was demonstrated to be a better planting method than transplanting.