1. School of Forestry & Landscape Architecture Anhui Agricultural University Hefei 230036 China
2. College of Agriculture and Biotechnology Zhejiang University Hangzhou 310058 China
3. Department of Agricultural Sciences, Viikki Plant Science Centre University of Helsinki PO Box 27 Helsinki FI‐00014 Finland
4. Institute of Agricultural and Environmental Sciences Estonian University of Life Sciences Kreutzwaldi 1 51006 Tartu Estonia
5. Estonian Academy of Sciences Kohtu 6 10130 Tallinn Estonia