Gene flow from cultivated to wild raspberries in Scotland: developing a basis for risk assessment for testing and deployment of transgenic cultivars

In order to help establish a basis for assessing the risk associated with the testing and large-scale deploymen of transgenic raspberries, wild and feral raspberry populations in Scotland were surveyed for evidence of the escape of genes introduced into raspberry cultivars by traditional breeding. The genes concerned were introduced into cultivars using traditional breeding techniques and were deployed at known times 20 to 30 years prior to the present survey. Escape of the semidominant L₁ gene, affecting fruit size and plant morphology, could not be detected after 30 years in test plots at the Scottish Crop Research Institute near Dundee. The recessive gene s, conferring spinelessness, was detected at very low frequencies (estimated at 0.004) in wild populations within the commercial production locales where cultivars carrying this gene had been introduced on a large scale beginning 21-years prior to this survey. This gene was not, however, found in any areas remote from the commercial production locales. The results of the survey indicate that escape does occur following large-scale deployment but that gene flow events are probably infrequent and spread is localized for genes having probable neutral selective value.