Stimulation of scion bud release by rol gene transformed rootstocks of Rosa hybrida L.

Abstract

For improvement of the root characteristics of roses, the rolA, B and C genes from Agrobacterium rhizogenes were introduced in the cultivar Moneyway, which is used as a rootstock. Four independent rolA+B+C transformants were produced. One rolC expressing transformant, showing good growth and clearly decreased apical dominance, was selected for a grafting experiment with the cut rose cultivar Madelon as a scion. Grafting on this rolA+B+C transformed rootstock resulted in a stimulation of both root development of the rootstock and axillary bud release of the untransformed scion. Axillary bud release increased from 0.1 to 0.6 and from 0.3 to 1.3 basal shoots per plant at 15°C and 20°C, respectively. Since basal shoots form flowers, this altered plant architecture will presumably lead to a more efficient flower production.