Abstract:

T3 and T4 homozygous lines of transgenic cotton, which was transformed with the betA gene coding for choline dehydrogenase from E. coli and the als gene coding for acetolactate synthase, were used for the study of biological characteristics and gene flow in the field. The results showed that some agronomic traits concerning with the survival competitive power of  the transgenic cotton with betA/als were significantly improved compared with the control of wild type lines Lumianyan19, such as reproductive capacity of seeds, seed vigor after storage and economic yield in salinealkali soil, while the value of micronaire was decreased. The other agronomic traits of the two kinds of cotton were resembled. One of the transgenic character obtained, resistance to herbicide, could be inherited stably and expressed well in the field. In the transgenic cotton release region with the area 6?m×6?m, the frequency of als gene introduced into the wild type cotton was reduced rapidly as the distance from the nontransgenic area to the release area increasing. Thus, making proper isolation distance (>200?m) could avoid the occurrence of exogenous gene escape. Yet some uncertain factors such as insects' effect on pollen spread should be considered before setting up the isolation area, and the isolation distance should be increased properly.

Key words:  transgenic cotton; field cultivation; herbicide resistance; gene flow; survival competitiveness