1. Center of Pear Engineering Technology Research, College of Horticulture, Nanjing Agricultural University, Nanjing, Jiangsu, China
2. College of Life Science, Nanjing Agricultural University, Nanjing, Jiangsu, China
3. State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, Jiangsu, China