Lisianthus(Eustoma grandiflorumGrise.) with novel flower colour patterns have been generated by genetic modification techniques that alter flavonoid biosynthesis. As described previously, the level and pattern of pigmentation in purple‐flowered lisianthus cultivars was altered by the introduction of a lisianthus chalcone synthase (CHS) cDNA in an antisense orientation. As the next step towards commercial development of these new cultivars, the consistency of altered flower patterns in the progeny and the performance of these lines under conditions resembling those used by commercial lisianthus growers in New Zealand have now been assessed. The introduced antisense CHS transgene had no apparent effect on germination rates or plant survival. Altered flower patterns observed in the progeny correlated with the inheritance of the transgenes, as measured by kanamycin resistance and reduction in CHS expression. At least two of the lines showed sufficient consistency in flower pattern to warrant continued development. Additionally, no transfer of the introduced DNA between transgenic and neighbouring non‐transformed lisianthus was observed during this trial.