Variation in the growth and development of narcissus in relation to meteorological and related factors

Bulb crops such as narcissus show commercially significant variations from year to year in such features as bulb and flower yields, dates of shoot emergence, flowering and foliage senescence, and responses to cold storage in bulb forcing. Examples of such variations, from both commercial crops and experimental work, are discussed. Meteorological factors which are likely to affect the growth and development of narcissus are reviewed: temperature and water availability are considered the most important factors. Narcissus crops also show poor within-crop uniformity, considered partly due to microclimatological and small-scale cultural differences within the planting ridge in planting density, depth and orientation. Elucidation of these responses could lead to formulating mathematical models for crop scheduling and changes in cultural methods to allow precision growing.