Exogenous IBA Controls Rooting of Camellia impressinervis

Abstract

Camellia impressinervis is a golden camellia whose yellow flowers have been widely used for healthcare. To produce seedlings from superior genotypes for intensive plantation, cutting propagation has been widely applied because of its simple technique and high rooting efficiency. In this study, the effect of different doses of exogenous indole-3-butyric acid (IBA) on the rooting efficiency of C. impressinervis was tested. The experiment included five doses (0.1, 0.2, 0.3, 0.4, and 0.5% by weight in powder) and a control (no hormone). Sand was used as the rooting medium. The results showed that IBA doses significantly affected the rooting efficiency of C. impressinervis. At 4 months of growth, the highest rooting rate (98.9%) was recorded with 0.5% IBA, decreasing to 86.7% with 0.1% IBA, while the lowest rooting rate was recorded in the control (73.4%). IBA doses also significantly affected mean root length (MRL). The longest MRL (4.46 cm) was recorded with 0.5% IBA, whereas the shortest MRL was found in the control (1.12 cm) and with 0.1% IBA (1.17 cm). The shoot number per cutting (2.3 shoots) was lowest with 0.5% IBA and was significantly lower than that at the other doses (>2.8 shoots). It is concluded that 0.5% IBA by weight in powder should be used to produce C. impressinervis seedlings by cutting propagation. Two leaves should be retained on each cutting, and two-thirds of each leaf area should be removed. The cutting bed should be maintained at >95% humidity and under 45-55% shading from direct sunlight.