1. Department of Horticulture, Zijingang Campus, Zhejiang University, Yuhangtang Road 866, Hangzhou 310058, China
2. Department of Botany & Plant Pathology, Purdue University, West Lafayette, IN 47907‐2054, USA
3. Key Laboratory of Horticultural Plants Growth, Development and Quality Improvement, Ministry of Agriculture of China, Zijingang Road 866, Hangzhou 310058, China