Rapid mass production of cauliflower propagules from fractionated and graded curd

Abstract

A new system of cauliflower micropropagation is described. The meristematic layer of the curd is removed and partially homogenised to disrupt the meristem clusters and then graded through precision sieves to produce homogenous size-classes. For a single curd, over 400 000 explants of size-class 0.1–0.3 mm can be produced. The explants are cultured following a two-step protocol. Shoot production uses an agitated liquid medium, explant size influences the number of shoots produced per explant with the optimal explant size-class of 0.1–0.3 mm allowing the production of one to three shoots per explant. Accurate control of the explant density in culture is required to produce good quality shoots and to control hyperhydricity. The number of ‘microshoots’ produced from one curd within 2 weeks is over 10 000. The rooting step takes place on a semi-solid medium in the presence of IBA, within 2 weeks over 80% of shoots are rooted. Plantlets are waned within 40 days following culture initiation. This protocol has the qualities of simplicity, large scale propagation, and high quality progagules, making it superior to conventional methods and a cost effective candidate for an industrial semi-automated system of propagule production.