AN OPTIMISED PROTOCOL FOR ROSE TRANSFORMATION APPLICABLE TO DIFFERENT CULTIVARS

The production of cut-flower roses makes a substantial contribution to the global floriculture industry.
Breeding programmes are driven by consumer requirements for novel and improved phenotypes, coupled to optimum production, disease and pest resistance.
Traditionally, new cultivars have been developed through sexual hybridisation.
However, this process is time consuming and by introducing one agronomically useful trait another may be eliminated.
For example, improvement of floral form and production over many decades has resulted in the loss of scent from many modern rose cultivars.
The introduction of specific genes into known rose cultivars could facilitate the generation of new cultivars with improved agronomic traits, without the problems associated with conventional breeding.
Plant phenotype, yield and resistance to pests and diseases are characteristics that can be manipulated on an individual basis.
In the present investigation, Agrobacterium tumefaciens-mediated transformation of embryogenic callus from a number of rose cultivars was optimised using the beta-glucuronidase (gus; uidA²) gene.
Stable integration of the transgene was confirmed at each stage of somatic embryogenesis and in regenerated plants.
An optimised protocol was used to deliver potentially agronomically useful transgenes into cultivars with the aim of improving flower production, disease resistance or re-introducing scent into those cultivars in which it was absent.
Results indicate that the manipulation of individual traits by genetic engineering in existing cultivars shows considerable promise and may be an adjunct in the future to conventional breeding.