1 Horticultural Crops Research Institute，Yunnan Academy of Agricultural Sciences，Kunming 650205，Yunnan，China；2 Yunnan University，Kunming 650504，Yunnan，China
Abstract：‘Yunyoumai No.1’is a new leaf lettuce cultivar developed by systematic selection of single plant from mixed population of local variety‘Longyanlvyewoju’．Its plant growth is strong．The plant height is 31-35 cm，with 40-45 cm divergence．Its leaves are lance-shaped，green in color，with smooth surface．The leaves taste crispy with good quality．There are 37-40 leaves in one single plant．The single plant weight is 270-300 g．It can yield about 36 t·hm-2 ．It is highly resistant to downy mildew，tolerant to bolting．It is suitable for year-round cultivation in the central region of Yunnan Province．It takes 50-55 days from fix planting to harvest in summer and autumn protected field cultivation．While，winter and spring protected field cultivation will take 60-65 days from fi x planting to harvest．
