Rosa hybrida ‘Radrazz’ rose bushes were studied. Internodes
bearing five- or seven-leaflet leaves were harvested from the
medial part of mother plant stems and used as single-node cuttings.
These cuttings were inserted into FERTISS peat plugs (FERTIL,
Le Syndicat, France), and rooting was achieved after 4–5 weeks
in humid conditions (miniature tunnels in a heated greenhouse).
Well rooted cuttings were planted in 500 ml pots containing a
50/40/10 mixture (v/v/v) of neutral peat, coconut fibers and perlite,
in which were transferred to a greenhouse (20 ◦C during
the day/16 ◦C at night, 16 h days and 8 h nights). Extra lighting
(100 mol m−2 s−1) was supplied by high-pressure sodium-vapor
lamps when PAR measurements outside the greenhouse fell below
112 mol m−2 s−1. As soon as the axillary bud of the cutting burst,
the young plants were transferred to one of the experimental
designs. The bud from the cutting produced the primary axis, the
apex of which transformed into a terminal flower bud. A variable
number of buds burst in the axils of leaves on the primary axis and
developed into secondary axes. Bud burst started approximately
when flower bud became visible (FBV stage) on the primary axis.
Most secondary axes produced a terminal flower bud but some
stopped developing before the floral bud became visible (blind
shoots). Plant development is presented in Fig. 1 and growing conditions
are summarized in Table 1.