The use of aseptic meristem culture in cauliflower breeding

Abstract

The upper surface of the cauliflower curd consists of a mass of apical meristems. These would normally develop into flowers, but if devernalised they revert to the vegetative phase and develop into leafy shoots. This property is being exploited by aseptically culturing portions of the curd in order to generate clones of selected material.

Selection of hydroxyproline-resistant proline-accumulating mutants of cauliflower (brassica oleracea var. botrytis)

“…The surface of the curd consists of thousands of apical meristems with single cells between them which are capable of dividing to give meristems . Scanning electron microscope studies (Crisp & Walkey, 1974) indicate that each meristem may become vegetative and give rise to a shoot . It is possible that one cell of a pre-formed meristem may have acquired the mutation resulting in over-production of proline, confering resistance on the whole meristem .…”

Selection against the bracting defect of cauliflower

“…Much less time and effort need be expended than in progeny testing these plants. In addition, the assessment of bracts in culture may be carried out as a complement to screening for anthocyanin production , to the vegetative propagation of selected plants (CRISP & WALKEY, 1974), and to the elimination of viruses from infected plants (WALKEY et al, 1975) any of which may be necessary in a breeding programme with cauliflower.…”

“…Other portions measuring 1.8-2.2 mm in diameter were taken from the surface of the parent curds, and were aseptically cultured in the solution of LINSMAIER & SKOOG (1965) by the method described by CRISP & WALKEY (1974). In the field, bracts are often irregularly distributed over the surface of the curd, and hence each parent was cultured in live replicates, and was characterised by the replicate which showed the greatest development of bracts.…”

“…It is therefore essential to develop techniques which maximise the expression of this character without interfering with the assessment of other characters. During the development of techniques for regenerating clonal plants by aseptically culturing the cauliflower curd (CRISP & WALKEY, 1974), consistent differences were noted between clones in the rates of development and the morphology of leaf-like organs. Certain of these leaves appeared to develop from the bracts inside the curd rather than from the meristemic apices constituting the curd surface.…”

The use of an evolutionary scheme for cauliflowers in the screening of genetic resources

“…The evidence is of two kinds: 1. The curd is believed to be a precociously developed floral button, made up of apical meristems, over 90% of which abort with the onset of flowering (CRISP & WALKEY, 1974). The excess tissue, and the egress of pathogens afforded by aborting tissue give the cauliflower a reduced chance of survival, and a low reproductive capacity in comparison with the broccoli.…”