Warm Storage of Narcissus Bulbs in Relation to Growth,Flowering and Damage Caused by Hot-Water Treatment

Three experiments are described on the effects on flowering of warm storage of narcissus bulbs before (and in some cases after) hot-water treatment (h.w.t.) against eelworm infection. Almost complete loss of the flower crop occurs if the bulbs are not warm stored, compared with the production of about 90% marketable flowers following warm storage. Optimum temperatures and durations of warm storage are not clearly defined; there is very little difference between the two recommended treatments, 34° C. for 3 days and 30° C. for 7 days, with the latter giving slightly better results. In another experiment, best results were obtained following 32·5° C. for 8 days or 35° C. for 5 days, with some varietal differences. These combinations were superior to most at 30° C., and to all of only 2 days duration. Higher temperatures and longer durations generally result in earlier flowering, with no adverse effect on flower quality. Bulb yield in the field following h.w.t. is higher when the bulbs are warm-stored before h.w.t. and, when forced in the following season, they give more flowers. Post-h.w.t. warm storage reduces flower quality and bulb yield in the field; although some minor benefits were observed, this treatment cannot be recommended. The possible mechanism for the protection afforded by warm storage is discussed.