1Potato Research Institute of Gansu Academy of Agricultural Sciences，Lanzhou 730070，Gansu，China；2Highland Cold Climate Agricultural Experiment Station of Gansu Academy of Agricultural Sciences，Lanzhou 730100，Gansu，China
Abstract：‘Longshu No.20’is a new potato variety，developed by crossing‘LK99’as female parent and‘Jizhangshu No.8’as male parent through sexual hybridization and systematic selection and breeding．It is of early-medium maturity．The growth period is about 89 days．It is of half-erect type．Its stem and leaves are luxuriant．The tubers are concentrated．The average tuber numbers per plant is 4.5．The rate of large and medium-sized tubers（＞ 75 g）is over 80%．The tuber is of oval shape．The tuber skin is smooth with shallow bud eyes．The tuber skin and flesh is all white in color．The single tuber weight is about 160 g．The dry matter content is 17.28%，crude starch content is 11.64%，crude protein content is 2.17%，VC content is 139.0 mg · kg-1，reducing sugar content is 0.29%．It can yield about 39 t · hm-2．Its resistance to late blight is stronger than that of the contrast‘LK99’．It is suitable for cultivation in Longnan，Tianshui，Lanzhou，Baiyin，Pingliang region of Gansu Province．
