Studies On Bt Rape Gene Flow Mediated By Soil Seed Bank

Huge application potential of transgenic rape will bring considerable benefits to crop production. However, the spread of transgenic gene, from transgenic rape to other rape varieties and wild relatives through gene flow, will bring new risks and great challenges to agriculture and ecological environment. Therefore, it has been given highly attention in academia and society. It is actually an urgent problem to be solved in the application of transgenic rape to crop production in order to establish effective technical measures to control transgenic escape and to reduce the risks of releasing transgenic rape to environment and the risks resulting from commercial production. Transgenic gene escape is dispersion via rape volunteers in soil seed bank and via pollen dispersion. In this studies, the gene flow mediated by soil seed bank and its influencing factors in the region of double cropping system in south China were analyzed, and some effective cultivation measures to control gene flow dispersion were brought forward. The main results were as follows:1. Reducing transgenic rape seed shedding during harvest was a key procedure to control gene flow. The amounts of seeds shedding was account for 1.18%~1.91% of rape yield, about 26.54～50.29 kg/hm~2, it equals to about 664～1257 seeds/m~2 fall into soil seed bank. The gene flow mediated by soil seed bank was lower when harvested rape by manual than that of by machine; the amounts of seeds shedding in transplanting rape was less than that of direct seeding rape; the shedding amount during sun drying was the most in three harvest procedures, it accounts for 73.82%～75.30%, natural shedding before harvest from rape plants was not took place. To reduce the shedding amount in sun drying was the key procedure to diminish the capacity of soil seed bank. The amount of shedding seeds in optimal harvest date was less than that of in late harvest date. Consequently, the amounts of rape seeds...