RolC-transgenic carnation with improved horticultural traits: Quantitative and qualitative analyses of greenhouse-grown plants

Expression of the rolC gene under the constitutive CaMV 35S promoter led to several advantageous alterations in transgenic carnation (Dianthus caryophyllus L. 'White Sim'). The rolC-transgenic carnation plants exhibited increased axillary budbreak and development when grown under standard commercial greenhouse conditions. Carnation with rolC generated up to 48% more stem cuttings per mother plant than nontransformed plants. Stem cuttings from rolC plants exhibited better rooting ability, with up to five times higher root dry weight than controls. The improved rooting of rolC-transgenic stem cuttings was also apparent when the cuttings were treated with IBA. During the flowering season, rolC-transgenic plants produced up to three times more flowering stems than control plants. It should be noted that the latter alterations, namely increased flowering and rooting, are of major importance to the carnation industry. Chemical name used: indole-3-butyric acid (IBA).