Relationships between the times of transplanting, curd initiation and maturity in cauliflower

Abstract

SUMMARYIn order to determine the accuracy of controlling the time of maturity of a cauliflower crop by regulating the planting date, a series of transplantings of the variety White Fox was grown on a range of sites over 3 years and sampled throughout growth.The time from transplanting to maturity and the time from curd initiation to maturity were both quadratically related to the time of transplanting but there were marked differences in the relationships between years. Differences between years in the time taken to reach maturity tended to increase with later transplanting; for example, cauliflower crops transplanted in May took between 77 and 94 days to mature, while those transplanted in July matured in as few as 67 or as many as 106 days. These differences resulted from a combined effect of the time taken to satisfy the vernalization requirement and the duration of curd growth, both of which are temperature-mediated and therefore subject to seasonal and annual variation. Differences in the vernalization requirements of different cauliflower crops are illustrated by the number of leaves formed before curd initiation, which varied from 22·5 to 37·3.Variation in the time to maturity between crops transplanted at similar times of the year, in the same and different years, resulted in large deviations from planned production programmes and it is suggested that a complementary technique to aid crop marketing would be prediction of the time of crop maturity. However, the data collected in this study show that predictions based on the duration of crop growth from transplanting or curd initiation are unlikely to be sufficiently accurate and it is argued that predictions should be based on changes in curd dimensions with time.