IN VITRO CULTURE TECHNIQUES FOR CARNATION BREEDING

1. Cell suspensions of the calli of ‘Arthur Sim’ (AS), ‘White Sim’ (WS), ‘Dark Purple’ (DP), ‘Lena’ (L), ‘Tangerina’ (TAN) and ‘Telestar’ (T) were cultured in MS (Murashige and Skoog, 1962) medium with (in mg 1^-1): 2,4-D (5), kinetin (1) and casein hydrolysate (CH) (500). After 7 d, cell proliferation was observed. ‘AS’ and ‘T’ formed multicellular colonies and microcalli.
   After 12 wks, differentiation into dark green nodules occured, but during subculture, further growth and differentiation were retarded.

2. Calli originated from stem segments of ‘AS’, ‘L’, ‘TAN’ and ‘T’ formed adventitious buds when subcultured in MS medium with NAA and kinetin (1 mg 1^-1, each). Rooting of adventitious buds gave flowering plants.
   No mutations were obtained.

3. Leaf rosette formation and axillary buds induction from meristem tips were achieved in MS medium with (in mg 1^-1) :2,4-D (0.02), IBA (0.1), 6-benzyladenine (BA) (2) and GA₃ (0.1). ‘TAN’, ‘Scania’ (SC), ‘DP’, ‘AS’, ‘L’, ‘WS’ and ‘T’ gave 42, 50, 73, 76, 90, 90 and 93% of newly-formed rosettes, respectively.
   MS multiplication medium contained (in mg 1^-1): NAA (0.2), IBA (0.02), kinetin or BA (0.01, 0.1 or 1.0). The choice of cytokinin depended on the cultivar responsiveness.
   Kinetin was more favourable for shoot multiplication of ‘T’, ‘L’ and ‘SC’, while BA was better for ‘AS’, ‘DP’, ‘TAN’ and ‘WS’. During shoot elongation GA₃ was omitted.
   Shoot rooting achieved in MS medium with or without IBA (0.5 or 1.0 mg 1^-1) and kinetin (0.05 mg 1^-1) varied from 71–100% for different cultivars.

During meristem culture of ‘DP’ shoots, medium containing plant growth stimulators and ancymidol was used.
Ancymidol in a concentration of 0.5 mg 1^-1 stimulated flowering, while higher levels of this compound inhibited this process.