Abstract: The stem sections of Cotoneaster hjelmqvistii plantlets in vitro were cultured in the medium supported by sandy loam soil and clay loam soil respectively for rooting, and the rooting rate and the root length of the plantlet cultured in the soil supporting medium were obviously higher than those of the plantlet cultured in the medium supported by agar. When cultured in the medium supported by the soil, the rooting rate and the root length of the plantlet in the medium without adding macro-elements were obviously higher than those in the medium with macro-elements added. In the medium supported by the clay loam soil, the rooting rate and the root length of the plantlet cultured in the medium without micro-elements and organic materials were obviously higher than those in the medium with micro-elements and organic materials added. Besides, in the medium supported by the clay loam soil, the rooting rate and the root length of the plantlet in the medium with sugar added were obviously higher than those of the plantlets cultured in the medium without sugar, and the rooting rate of the plantlet in the medium with 1.5% sugar was 93.3%, which were obviously higher than that of plantlet in the medium with 0.75% sugar. These results can reduce the cost and lay a foundation for simplifying the transplanting procedure of the Cotoneaster hjelmqvistii plantlets in vitro.

Key words: Cotoneaster hjelmqvistii, plantlet in vitro, soil supporting, culture medium, rooting culture