PROBLEM TO BE SOLVED: To improve the productivity of clone seedlings by accelerating rooting from the shoots of plants to improve the rooting rate. SOLUTION: The shoots of the plants are cultivated in the presence of a yeast extract to attain rooting from the shoots. The yeast extract in use preferably contains at least 90 mass% ribonucleic acid or its salt per the whole mass of the yeast extract. Cultivation in the presence of the yeast extract is achieved by bringing a rooting medium that contains the yeast extract, into contact with the shoots. A large amount of clone seedlings can thereby be quickly produced from the shoots of plants, and finding a way to its industrial use can be expected. COPYRIGHT: (C)2013,JPO&INPIT
