1. State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming 650201, China
2. College of Landscape Architecture and Horticulture, Yunnan Agricultural University, Kunming 650201, China
3. Modern Education Technology Center, Yunnan Agricultural University, Kunming 650201, China
4. USDA-ARS, National Germplasm Resources Laboratory, Beltsville, MD 20705, U.S.A.