Abstract: Transgenic sorghum plant have been obtained after microprojectile bombardment of immature embryo or inflorescence explants. DNA delivery parameters were optimized based on transient expression R and C1 maize anthocyanin regulatory elements or gusA. The protocol for obtaining transgenic plants consisted of delivery of the bar gene to explants and imposition of bialaphos selection pressure at various stages during culture, from induction of somatic embryogenesis through rooting of regenerated plants. The presence of the transgenes was confirmed by PCR and Southern blot analysis. The herbicide resistant phenotype was inherited by progeny derived from the primary regenerant.

Figure legend. Selection of transformed sorghum (cultivar P898012) callus, plant regeneration, and herbicide resistance of transgenic plants. (A) Immature zygotic embryo on induction medium containing bialaphos at 1 ug/ml. (B) Embryogenic callus on maintenance medium with bialaphos at 3 ug/ml. (C) Plant regeneration on medium with bialaphos at 3 ug/ml. (D) Untransformed (left) and transformed (right) regenerated plants 48 hr after local application of herbicide to the leaves (arrows). (E) Leaves from four untransformed control plants (from the left, nos. 1and 2 were seed derived, and nos. 3 and 4 were regenerated) and three transformed plants, 4 days after treatment with the herbicide.