title: Innate factors causing differences in gene flow frequency from transgenic rice to different weedy rice biotypes.
abstract: BACKGROUND
  The compatibility and outcrossing rates between transgenic rice and weedy rice biotypes have been studied in some previous cases. However, few studies have addressed the reasons for these differences. The present study compared the compatibility and outcrossing rates between transgenic rice and selected weedy rice biotypes using manual and natural crossing experiments to elucidate the key innate factors causing the different outcrossing rates.
  
  
  RESULTS
  Hybrid seed sets from manual crossing between transgenic rice and weedy rice varied from 31.8 to 82.7%, which correlated directly with genetic compatibility. Moreover, the significant differences in the quantity of germinated donor pollens and pollen tubes entering the weedy rice ovule directly contributed to the different seed sets. The natural outcrossing rates varied from 0 to 6.66‰. The duration of flowering overlap was the key factor influencing natural outcrossing. Plant and panicle height also affected outcrossing success.
  
  
  CONCLUSIONS
  From this study, it is concluded that the likelihood of gene flow between transgenic rice and weedy rice biotypes is primarily determined by floral synchronisation and secondarily influenced by genetic compatibility and some morphological characteristics.
authors.affiliation: Weed Research Laboratory, Nanjing Agricultural University, Nanjing, China.
authors.forename: Jiao
authors.initials: J
authors.lastname: Zuo
authors.forename: Lianju
authors.initials: L
authors.lastname: Zhang
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Song
authors.forename: Weimin
authors.initials: W
authors.lastname: Dai
authors.forename: Sheng
authors.initials: S
authors.lastname: Qiang
mesh_terms: D000613:Aminobutyrates / Q000494:pharmacology; D002678:Chimera / Q000235:genetics / Q000502:physiology; D002681:China; D051456:Gene Flow / Q000502:physiology*; D053209:Herbicide Resistance / Q000235:genetics; D006540:Herbicides / Q000494:pharmacology; D006824:Hybridization, Genetic / Q000502:physiology*; D012275:Oryza / Q000145:classification / Q000235:genetics* / Q000254:growth & development / Q000502:physiology*; D056771:Ovule / Q000502:physiology; D010802:Phylogeny; D030821:Plants, Genetically Modified / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D011058:Pollen / Q000502:physiology; D054817:Pollination / Q000502:physiology; D012639:Seeds / Q000235:genetics / Q000254:growth & development; D019076:Transgenes / Q000235:genetics
chemical_list: D000613:Aminobutyrates; D006540:Herbicides; C003121:phosphinothricin