Abstract：‘Longzi No.9’is a new variety of purple sweet potato，bred by natural hybridization with‘Longzi No.10’as female parent，‘Lingzi’‘Vietnam purple sweet potato’‘Longzi No.4’and‘Ningzi No.1’etc. purple sweet potato varieties as paternal group．Its tuber is of spindle shape with deep purple peel and purple flesh．The single plant can bear 4-5 tubers．The average proportion of large potato is 86.2%，that of commercial potato is 87.4%．The anthocyanin content is 253 mg·kg-1（FW）．The average fresh root yield is 36 t·hm-2．The dried root yield is 9 t·hm-2．It is suitable for summer and autumn potato planting in Fujian，Jiangxi，Guangdong，Guangxi，Sichuan，Guizhou etc. areas not affected by potato blast and cranberry disease．
