title: Evaluation of pollen dispersal and cross pollination using transgenic grapevine plants.
abstract: Public debate about the possible risk of genetically modified plants often concerns putative effects of pollen dispersal and out-crossing into conventional fields in the neighborhood of transgenic plants. Though Vitis vinifera (grapevine) is generally considered to be self-pollinating, it cannot be excluded that vertical gene transfer might occur. For monitoring pollen flow and out-crossing events, transgenic plants of Vitis vinifera cv. 'Dornfelder' harboring the gus-int gene were planted in the center of a field experiment in Southwest Germany in 1999. The rate of pollen dispersal was determined by pollen traps placed at radial distances of 5-150 m from the pollen-donor plants, at 1.00 and 1.80 m above ground. Transgenic pollen was evaluated by GUS staining, and could clearly be distinguished from pollen originating from non-transgenic grapevine plants. Transgenic pollen was observed up to 150 m from the pollen donors. The rate of out-crossing was determined by sampling seeds of selected grapevines at a distance of 10 m to the pollen source, and of a sector at 20 m distance, respectively, followed by GUS analysis of seedlings. The average cross-pollination rate during the experiment (2002-2004) was 2.7% at a distance of 20 m. The results of this first pilot study present a good base for further assessment under the conditions of normal viticulture practice.
authors.affiliation: Julius Kühn-Institute (JKI), Federal Research Centre for Cultivated Plants, Institute for Grapevine Breeding Geilweilerhof, Siebeldingen, Germany. margit.harst@jki.bund.de
authors.forename: Margit
authors.initials: M
authors.lastname: Harst
authors.forename: Beatrix-Axinja
authors.initials: BA
authors.lastname: Cobanov
authors.forename: Ludger
authors.initials: L
authors.lastname: Hausmann
authors.forename: Rudolf
authors.initials: R
authors.lastname: Eibach
authors.forename: Reinhard
authors.initials: R
authors.lastname: Töpfer
mesh_terms: D000383:Agriculture; D004784:Environmental Monitoring; D030821:Plants, Genetically Modified; D011058:Pollen; D054817:Pollination / Q000502:physiology*; D013997:Time Factors; D027843:Vitis / Q000235:genetics*; D014919:Wind