The effect of ensiling on PCR-based defection of genetically modified Bt maize

The detection of the genetic modification in silage obtained from insect-re sistant Bt maize by means of the polymerase chain reaction (PCR) is describ ed. The detectability of the transgene was shown to be dependent on the len gth of the genomic target sequence chosen for amplication by the PCR. By am plifying a Bt-maize-specific DNA sequence of 211 bp the genetic modificatio n was detected up to 7 months after ensilage. The effect of maize DNA degra dation in the course of the ensilage on the detectability of target sequenc es was demonstrated in model experiments.