1. College of Horticulture, Gansu Agricultural University, Lanzhou, China
2. College of Agriculture and Forestry Science, Linyi University, Linyi, China
3. Department of Horticulture, University for Development Studies, Tamale, Ghana
4. Gansu Provincial Key Laboratory of Arid Land Crop Science, Gansu Agricultural University, Lanzhou, China
5. Department of Biology, College of Science and Mathematics, California State University, CA, USA
6. College of Plant Protection, Gansu Agricultural University, Lanzhou, China