Selection of the transformed plant cells is traditionally accomplished by the introduction of an antibiotic or herbicide resistance gene,enabling transformed cells to survive on a medium containing a selective agents.The nptⅡ,hpt,and bar genes are frequently used to select transformed plant tissues.There are some concerns,however,regarding the safety issues of these markers existed in genetically modified organisms(GMOs).The avoidance of antibiotic or herbicide resistance markers in GMOs has been en...