Factors causing small curds in cauliflower crops

Abstract

Vigorous cauliflower plants sometimes bear abnormally small curds, yet this common problem has received little recognition or attention from research workers. Curd size is often reduced towards the end of the harvesting period of a crop, and this is more marked if environmental conditions reduce mean curd size and lengthen the time to maturity. Small late curds may be a consequence of their slow growth rather than their late initiation. Cultivars differ in their tendency to produce plants with late maturity and small curds. This may not be due to genetic differences within cultivars. Moreover, breeding to eliminate or reduce this condition may not be possible without affecting overall maturity time and curd size. INTRODUCTIONThere is often considerable wastage of cauliflowers because proportions of crops mature too early or too late, and are of poor quality and size. Improved cultivars have brought some improvements in uniformity and yield, as has better husbandry (Whitwell, 1969), but problems still remain with the variability and unpredictability of cauliflowers.In particular, vigorous plants can bear curds which are too small to be marketed, with no effect attributable to pest, disease or inadequate husbandry. This is a characteristic of winter-maturing cauliflowers grown in the south-west of Britain. The character is, however, common in most cauliflowers, but receives less attention than it deserves because such curds are usually part of the continuous distribution of curd size found within each crop. Additionally, small size has not until recently been a reason for classing curds as 'non-marketable' in official British trials (Chowings, 1974;Ramsbottom, 1974) and thus the magnitude of the problem has not been generally apparent.It is the purpose of this paper to draw attention to the problem, to comment on differences between cultivars, and other genetic effects, and to suggest a possible association between the appearance of small curds and other physiological factors.

Sink development, phyllotaxy, and dry matter distribution in a large inflorescence

“…We know that weight per curd approaches an asymptotic value as the date of harvesting approaches and there is some evidence to link this value with the mass or area of leaves per plant ; but the relationship between size of source' and (eventual) size of `sink' in cauliflowers is in general not very close, and it is far from clear why cauliflowers stop growing when they do . For example, why do small cauliflowers [9] not just continue to grow until they are `large'?…”