1. School of Horticulture and Plant Protection Yangzhou University Yangzhou 225009 China
2. Joint International Research Laboratory of Agriculture and Agri‐Product Safety Yangzhou University Yangzhou 225009 China
3. Horticulture Department University of Wisconsin Madison WI 53706 USA
4. USDA‐ARS Vegetable Crops Research Unit 1575 Linden Drive Madison WI 53706 USA