Postharvest Losses from Delayed Harvest and during Common Storage of Short-day Onions

Abstract

A 2-year field study was conducted to evaluate the effects of maturity and storage on fresh-market onion (Allium cepa L.) quality. Four short-day onion cultivars (`NuMex BR1', `NuMex Sunlite', `NuMex Starlite', and `Buffalo') were seeded in early October each year. Bulbs were harvested at five times; the first and second harvests were when 20% and 80 %, respectively, of the bulbs in a plot had mature necks; the third, fourth, and fifth harvests were at 5,10, and 15 days after the second harvest date, respectively. After curing for 3 days, bulb firmness, weight, and incidence of disease were evaluated for all harvests. Bulbs were re-evaluated after 10 and 20 days storage in a shed under ambient conditions. `Buffalo' and `NuMex Surdite' bulbs had the lowest incidence of disease before storage. For all cultivars, average bulb weight increased and firmness decreased with delayed harvest. Percent diseased bulbs increased for all cultivars as harvest was delayed in 1991 but not in 1992. The optimum harvest time was at 80% maturity. In storage, average bulb weight and firmness decreased, and the incidence of bulb diseases increased.