Development of cauliflower and its consequences for cultivation

<p>From a number of cauliflower crops, grown during several years, plant development was related to the environmental conditions (mainly temperature). After transplanting three developmental phases could be recognized: juvenility, curd induction and curd growth, Variation in time of curd maturity was mainly due to a variation in time of curd initiation (morphological transition of the apex). Time of curd initiation was determined by the time on which juvenility (characterized by the number of initiated leaves) ended and temperature during the period after juvenility. Higher temperatures during the period of curd induction delayed curd initiation and increased the total number of initiated foliage leaves of a plant.<p>Curd induction could be affected by a GA <sub><font size="-1">4+7</font></sub> application, resulting in an advance of curd maturity, especially when curd initiation of a crop was delayed due to high temperature.<p>Curd weight at maturity was reduced if plant weight at the time of curd initiation was low, conditions which enhanced development but reduced growth caused buttoning.<p>Bracting was induced by high temperature, and when ethephon was applied just after all plants within a crop had initiated a curd, bracting incidence was enhanced severely. Genetic differences in sensitivity for bracting induced by ethephon were apparent.<p>Prospects of cultural measures to reduce the variation in time of maturity in relation to rapidly changing environmental conditions are discussed