title: Gene flow in maize fields with different local pollen densities.
abstract: The development of maize (Zea mays L.) varieties as factories of pharmaceutical and industrial compounds has renewed interest in controlling pollen dispersal. The objective of this study was to compare gene flow into maize fields of different local pollen densities under the same environmental conditions. Two fields of approximately 36 ha were planted with a nontransgenic, white hybrid, in Ankeny, Iowa, USA. In the center of both fields, a 1-ha plot of a yellow-seeded stacked RR/Bt transgenic hybrid was planted as a pollen source. Before flowering, the white receiver maize of one field was detasseled in a 4:1 ratio to reduce the local pollen density (RPD). The percentage of outcross in the field with RPD was 42.2%, 6.3%, and 1.3% at 1, 10, and 35 m from the central plot, respectively. The percentage of outcross in the white maize with normal pollen density (NPD) was 30.1%, 2.7%, and 0.4%, respectively, at these distances. At distances greater than 100 m, the outcross frequency decreased below 0.1 and 0.03% in the field with RPD and NPD, respectively. A statistical model was used to compare pollen dispersal based on observed outcross percentages. The likelihood ratio test confirmed that the models of outcrossing in the two fields were significantly different (P is practically 0). Results indicated that when local pollen is low, the incoming pollen has a competitive advantage and the level of outcross is significantly greater than when the local pollen is abundant.
authors: Department of Agronomy, 166 Seed Science Center, Iowa State University, Ames, IA 50011, USA. susana@iastate.edu
authors: A Susana
authors: AS
authors: Goggi
authors: Higinio
authors: H
authors: Lopez-Sanchez
authors: Petrutza
authors: P
authors: Caragea
authors: Mark
authors: M
authors: Westgate
authors: Raymond
authors: R
authors: Arritt
authors: Craig A
authors: CA
authors: Clark
mesh_terms: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics; D001427:Bacterial Toxins / Q000235:genetics; D003433:Crosses, Genetic; D004731:Endotoxins / Q000235:genetics; D051456:Gene Flow; D017343:Genes, Plant; D005998:Glycine / Q000031:analogs & derivatives; D006460:Hemolysin Proteins / Q000235:genetics; D008685:Meteorological Concepts; D008954:Models, Biological; D030821:Plants, Genetically Modified; D011058:Pollen / Q000235:genetics / Q000502:physiology; D003313:Zea mays / Q000235:genetics* / Q000502:physiology; D000097797:Glyphosate
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D005998:Glycine; D006460:Hemolysin Proteins; D000097797:Glyphosate; C030956:insecticidal crystal protein, Bacillus Thuringiensis