2013 ASHS Annual Conference

Leaf length above the bulb at topping, or drying length has been considered one of the important factors for storage quality, but varies, depending on labors or growing regions. The study was executed to evaluate the effect of topping timings, drying length, and leaf length above the bulb at topping in relation with different harvesting times on storage quality of onion bulbs. For topping timing treatments, onions were topped at the harvest date and after field drying for a couple of days. For drying length treatment, onions were dried in the field for 1, 3, and 5 days. For leaf length treatments, onions were cut at 1 cm, 4 cm, 7 cm and 10 cm above the bulb at 90% top-down and 10 days after 100% top-down. Bulb rot loss was not affected by topping timings in cold storage. Longer leaf drying decreased bulb rot loss. Storage bulb rot decreased with increased leaf length above the bulb at topping, the effect of which was enhanced by harvesting at 10 days after 100% top-down. When leaf length above the bulb was short at topping, topped site was main target for some diseases such as Botrytis bulb rot or bacterial soft rot.