Use of hi ii-elite inbred hybrids in Agrobacterium-based transformation of maize
- Cite this article as:
- Horn, M.E., Harkey, R.L., Vinas, A.K. et al. In Vitro Cell.Dev.Biol.-Plant (2006) 42: 359. doi:10.1079/IVP2006776
Hybrid embryos resulting from crosses between a highly regenerable maize germplasm (Hi II) and certain elite inbreds were treated with Agrobacterium tumefaciens containing the uidA (GUS) and pat genes under the control of different constitutive promoters. Six of the elite inbred lines were derived from a Lancaster background and three were derived from an Iowa Stiff Stalk background. Hybrid embryos from all three Stiff Stalk lines gave transgenic events at various frequencies, two of them at a comparable frequency to that observed with Hi II embryos. Embryos from only one Lancaster/Hi II hybrid were successfully transformed and the frequency was quite low. Additional Lancaster elite inbreds were then tested as a hybrid with Hi II and failed to produce a single transgenic event. The transgenic Hi II/elite events showed many characteristics of ‘hybrid vigor’ including more aggressive rooting, thicker stems, and taller stature than plants derived from Hi II events. The hybrid T0 plants exhibited excellent tassel development in the greenhouse with abundant pollen shed. Seed set in the greenhouse was significantly (3–5-fold) higher than with Hi II transformats. Attempts to transform embryos derived from self or sibling crosses of the four inbred lines that were successful as hybrids with Hi II did not produce any transgenic events. T0 plants having ∼50% elite genomic contribution perform nearly as well in the greenhouse as seed-derived elite inbred parents and offer a significantly reduced time line for recombinant protein product development from transgenic plants.