1. Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, Changsha 410205, P. R. China
2. Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing 100093, P. R. China
3. Graduate School of Chinese Academy of Agricultural Sciences, Beijing 100081, P. R. China
4. Department of Food and Biotechnology Engineering, Chongqing Technology and Business University, Chongqing 400067, P. R. China