H Cui1, C Wu1, Q Zhu1, C Fan2, P Gao1, F Luan1. 1. College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin, Heilongjiang 150030, China, and Key Laboratory of Biology and Genetic Improvement of Horticulture Crops (Northeast Region), Ministry of Agriculture, Harbin, Heilongjiang 150030, China. 2. College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin, Heilongjiang 150030, China, Key Laboratory of Biology and Genetic Improvement of Horticulture Crops (Northeast Region), Ministry of Agriculture, Harbin, Heilongjiang 150030, China, and Hainan Base of Heilongjiang Agriculture Academy, Sanya, Hainan, 572000, China.