ABSTRACT

Cineraria seeds are sown sparingly, about 4-5 seeds per inch, in very shallow trenches of prewetted vermiculite or other suitable seedling mix and then lightly covered with medium. We have found that a 11 × 21 inch plastic at of seedlings will provide enough material for a class of 10-15 students. Cover the trays with plastic wrap and incubate at 21°C with about 50 µmol.m−2.s−1 of light provided by cool uorescent tubes. If a growth chamber is unavailable, a benchtop in a cool laboratory will work well. The plastic wrap should be removed after the seedlings emerge in about 10 to 14 days. The rst true leaves will be formed after an additional one to two weeks and are suitable for explants. Flower formation requires about 26-28 weeks of growth, including some time in a cooler. Five weeks after sowing, seedlings are transplanted into bedding plant cell packs. After 4 weeks, plants are moved up to 4-inch pots (any soilless medium will do) and, after an additional four weeks of growth, plants are placed in a cooler at 15°C. The plants are moved after six weeks to a cool greenhouse (about 18°C) and should ower between 8-10 weeks later (see Larsen, 1985, for scheduling). For receptacle explants, choose ower buds that are showing slight color but are more or less tightly closed.