STUDY ON THE CLONAL PROPAGATION OF Camellia caudata BY STEM CUTTING METHOD

Abstract

This study was conducted to determine the effects of plant growth regulators, cutting type, and season on the rooting ability of Camellia caudata cuttings propagated by the stem-cutting method. The experiment was arranged in a completely randomized design with the following factors: two plant growth regulators (IBA and NAA) at four concentrations (500 - 2,000 ppm); three cutting positions on the shoot (apical, middle and basal) collected from two categories of stock plants (pre-reproductive and reproductive) and four cutting seasons (spring, summer, autumn, and winter). The results showed that both IBA and NAA significantly enhanced rooting, with IBA at 1,500 ppm producing the best performance, yielding a rooting rate of 73.3%, an average of 8.9 roots per cutting, a root length of 4.4 cm and a rooting index of 39.2 (p < 0.001). Middle and basal cuttings from pre-reproductive stock plants exhibited the highest survival, rooting percentage, and rooting index (34.8 - 45.9), whereas apical cuttings and those from reproductive plants performed considerably lower. Rooting was strongly influenced by season, with spring and autumn being the most favorable periods, resulting in high rooting percentages (73.3 - 76.7%) and high rooting indices (35.3 - 37.8). The study demonstrates that combining 1,500 - ppm IBA with basal or middle cuttings from pre-reproductive stock plants and conducting propagation in spring or autumn, provides the optimal approach for clonal propagation of Camellia caudata, thereby improving propagation efficiency and supporting the conservation of this valuable genetic resource.