Rooting Quality of Hibiscus syriacus Cuttings Treated with Different Growth Regulators

In December 2021, 1-2-year branches were collected from over 3-year mother Hibiscus syriacus trees in Lishui, Zhejiang province for cutting. Rooting rate, average root number, average root diameter, maximum root diameter, average root length and the longest root length of cuttings treated by different kind and concentration of growth regulator were determined by orthogonal experimental design with 3 factors and 3 levels and by principal component analysis. The results showed that every treated cutting had 95% rooting rate, rooting index of different treatments were positively correlated. The comprehensive rooting quality of cuttings treated with 100 mg/kg1 of IBA for 3 hours, that with 200 mg/kg1 of GA for 2 hours and that with 100 mg/kg1 of IAA for 1 hour had better effect than the average. The experiment demonstrated that the best treatment was 100 mg/kg1 of IBA for 3 hours.