1. National Citrus Engineering and Technology Research Center, Citrus Research Institute, Southwest University, Beibei, Chongqing 400712, China
2. Academy of Agricultural Sciences, Southwest University, Chongqing 400715, China
3. College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400715, China
4. USDA-ARS, National Germplasm Resources Laboratory, Beltsville, MD 20705, U.S.A.