[Problem] To provide a novel technique capable of promoting effective tillering of plants such as rice. A microbial material superheated steam treatment product obtained by subjecting a mixture containing yeast, yeast extract or yeast cell wall, and phosphoric acid or a phosphoric acid compound and potassium or potassium compound to superheated steam treatment is provided. Contains an effective tiller promoter. Preferably, a method for promoting effective tillering, comprising treating the microbial material superheated steam-treated product with a gramineous plant. More preferably, the method of promoting the effective tiller processing to a gramineous plant by foliar-spreading this microbial material superheated steam treatment thing. [Selection figure] None【課題】稲科等の植物の有効分げつを促進できる新規な技術の提供。【解決手段】酵母、酵母の抽出物、又は酵母の細胞壁と、リン酸又はリン酸化合物及びカリウムまたはカリウム化合物と、を含む混合物に過熱水蒸気処理を施すことにより得られる微生物材料過熱水蒸気処理物を含む、有効分げつ促進剤。好ましくは、該微生物材料過熱水蒸気処理物をイネ科植物に処理することを含む、有効分げつを促進する方法。より好ましくは、該微生物材料過熱水蒸気処理物を葉面散布することにより、イネ科植物に処理する有効分げつを促進する方法。【選択図】なし
