A STUDY OF GENE DISPERSAL VIA POLLEN IN NICOTIANA-TABACUM USING INTRODUCED GENETIC-MARKERS

1. Agrobacterium tumefaciens was used to introduce two marker genes (k anamycin resistance and beta glucuronidase) into tobacco. 2. These pla nts were grown in a series of field trials each consisting of a small plot of modified plants surrounded at various distances (1 m, 10 m, 20 m) by non-modified receptor plants. 3. Capsules from these receptor p lants were harvested and samples of the seed were germinated on kanamy cin-containing medium in laboratory conditions, as a screen for the pr esence of the resistance gene. Large populations of seed could be scre ened in this way. 4. Using these techniques, gene flow from the 'marke d' plants could easily be detected. Although there were some differenc es in the absolute degree of gene dispersal in the different trials, t here was an overall decline in transfer as distance from the marked pl ants increased. 5. The potential for the use of introduced genetic mar kers in the study of gene flow is discussed.