Transgenic line 959A was developed using recombinant DNA techniques to produce flowers with a unique deep purple colour by introducing two genes that function together in the biosynthesis of the anthocyanin pigment delphinidin. The transgenic line was derived from the parent cultivar ‘White Unesco’, which is a white coloured carnation that was selected for a mutation in the dihydroflavonol reductase (DFR) encoding gene that did not allow for expression of a functional enzyme, and thus did not produce the anthocyanin type pigments that give rise to blue and red coloured flowers.

The two genes introduced into the transgenic carnation line included a functional dihydroflavonol reductase encoding gene isolated from petunia (Petunia hybrida) and a gene encoding the enzyme flavonoid 3’, 5’-hydroxylase (F3’, 5’H), a member of the NADPH-Cytochrome P450 reductase family, isolated from Viola. Expression of the F3’, 5’H encoding gene (bp40) allows for the production of blue coloured delphinidin anthocyanin pigments, which are not normally found in carnations.

Tolerance to sulfonyl urea herbicides was produced via the introduction of a chlorsulfuron tolerant version of the acetolactate synthase (ALS) encoding gene from tobacco.