Effects of Temperature and Plant Growth Regulators on the Scale Propagation of Lilium davidii var. unicolor

Scale propagation is a cost-effective and time-saving reproduction method for lily bulb production. The effects of different incubation temperatures and plant growth regulators on the scale propagation of Lilium davidii var. unicolor were investigated. The results showed that temperature influences the scale rot incidence rate, speed of scale differentiation and bulblet formation, as well as the size of bulblets. The optimum temperature for scale propagation of L. davidii var. unicolor was 30 degrees C. Scales incubated at 30 degrees C showed a lower rot incidence and faster differentiation and produced larger bulblets. The application of gibberellic acid (GA(3)), 1-naphthaleneacetic acid (NAA), and 6-benzylaminopurine (6-BA) had no significant influence on the differentiation rate of scales. GA(3) application reduced the incidence rate of scale rot. However, treatment with 50 mg/L NAA and 2 mg/L 6-BA significantly increased the rot incidence rate in the second week of propagation. Both treatments with 100 mg/L NAA and 100 mg/L GA(3) produced a higher number of bulblets than their controls after 6 weeks of incubation. GA(3) at 100 and 150 mg/L increased the diameter of bulblets, resulting in more large bulblets (grade 1) and fewer small bulblets (grade 3). 6-BA did not facilitate propagation by scaling.