Sericulture is an important industry for silk production in Southern China. Typi cally, mulberry （Morus L.） plants are grown on the ridge of or beside rice fiel ds in this area, the so-called mulberry-rice mixed cropping area. The allowing o f limited environmental release, and presumable commercial release later, of Bt (Bacillus thuingiensis) transgenic rice (Oryza sativa L.) by China raise d a doub t that if Bt transgenic rice pollen, which will be wind-dispersed on mulberry l e aves, is harmful for ser...