Transgenic radish (Raphanus sativus L. longipinnatus Bailey) by floral-dipmethod - plant development and surfactant are important in optimizing transformation efficiency

Transgenic radish (Raphanus sativus L. longipinnatus Bailey) plants were pr oduced from the progeny of plants which were dipped into a suspension of Ag robacterium carrying both the beta -glucuronidase (gusA) gene and a gene fo r resistance to the herbicide Basta (bar) between T-DNA border sequences. T he importance of development of the floral-dipped plant and presence of sur factant in the inoculation medium were evaluated in terms of transgenic pla nt production. Plants dipped at the primary bolt stage of growth, into a su spension of Agrobacterium containing 0.05% (v/v) Silwet L-77 resulted in op timum transformation efficiency, with 1.4% from 1110 seeds. The presence of Pluronic F-68 or Tween 20 in the inoculation medium was beneficial towards transgenic plant output compared to treatments without surfactant. Putativ e transformed T1 plants were efficiently selected by spraying with 0.03% (v /v) Basta and all herbicide-resistant plants tested positive for GUS activi ty when analysed both histochemically and fluorometrically. Southern analys is revealed that both the gusA and bar genes integrated into the genome of transformed plants and segregated as dominant Mendelian traits. These resul ts demonstrate that radish can be genetically modified for the improvement of this important vegetable crop.