Factors affecting the growth of carnation plants from shoot apices

SUMMARY Carnation plants were grown from shoot apices ranging from 200 μ to 1 mm. in length, derived from plants of different ages, at all times of the year. Tips grew best in small tubes on a simple nutrient medium, supported on wicks of ashless filter paper. The presence of rooting hormone in the medium was essential during the early stages of culture. Rooting was affected by the size of the tips and the time of year at which they were excised. Rooting of tips after heat treatment of the parent plants differed with variety, and virus infection also affected the rooting of some varieties.