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The use of plant genetic engineering to augment plant breeding programs is significantly strengthened if novel trait(s) can be introduced directly into elite germplasm. Implementing this technology to sorghum breeding programs has been hampered by the lack of an efficient and transferable protocol that is suitable with elite genotypes. This study was conducted to identify parameters that maximize in vitro culture performance in sorghum targeting a specific elite genotype, C2-97, which possesses enhanced agronomic characteristics. Three different tissue culture media formulations, MS, N6, and M11 were evaluated. M11 medium contains approximately 16% and 85% more total nitrogen and sevenfold and threefold higher levels of potassium phosphate than MS and N6 formulations, respectively. Culture performance of C2-97 across the three media formulations was compared to sorghum genotypes that were previously reported to be amenable to genetic engineering, namely Tx430, P898012, Bwheatland, and C401. Maxim...

A binary vector, pPTN133, was assembled that harbored two separate T-DNAs. T-DNA one contained a bar cassette, while T-DNA two carried a GUS cassette. The plasmid was mobilized into the Agrobacterium tumefaciens strain EHA101. Mature soybean cotyledonary node explants were inoculated and regenerated on medium amended with glufosinate. Transgenic soybeans were grown to maturity in the greenhouse. Fifteen primary transformants (T0) representing 10 independent events were characterized. Seven of the 10 independent T0 events co-expressed GUS. Progeny analysis was conducted by sowing the T1 seeds and monitoring the expression of the GUS gene after 21 d. Individual T1 plants were subsequently scored for herbicide tolerance by leaf painting a unifoliate leaf with a 100 mgl−1 solution of glufosinate and scoring the leaf 5 d post application. Herbicide-sensitive and GUS-positive individuals were observed in four of the 10 independent events. Southern blot analysis confirmed the absence of the bar gene in the GUS positive/herbicide-sensitive individuals. These results demonstrate that simultaneous integration of two T-DNAs followed by their independent segregation in progeny is a viable means to obtain soybeans that lack a selectable marker.