Tissue culture and transformation studies with selected genotypes of soybean (Glycine max (L.); Merr.)

Experiments were done to examine culture parameters involved in somatic embryo induction and culture for the soybean genotypes Bragg and its non- and super-nodulating mutants, TN4-86, TN90-03, TN90-09, and the control Fayette. Broad genotypic differences were found in the response of soybean genotypes to induction of somatic embryogenesis in immature cotyledons and in the establishment of sustainable embryogenic suspension cultures. Genotypes Bragg and TN4-86 produced sustainable embryogenic suspension cultures but Bragg was non-regenerable. TN4-86 could be regenerated from suspension culture.; Two TN4-86 plants were regenerated from embryogenic suspension culture. Progeny were examined for the embryogenic phenotype in culture. The embryogenic phenotype did not seem to be controlled by a single locus. Field assessement through the R{dollar}sb4{dollar} generation showed somaclonal variation. Dwarfism, 'partial steriles', and differences in maturity dates were detected. Genomic DNA's from the R1 progeny were analyzed by single primer DNA Amplification Fingerprinting (DAF) but no polymorphisms were detected among the progeny.; Plasmids were obtained for transformation studies. A plasmid construct was made for soybean transformation that contained the soybean mosaic virus coat protein (smv-cp). Herbicide selection experiments were done in vitro and in vivo to determine the effective concentrations of phosphinothricin herbicidal compounds on soybean tissues. Plant absorption of the different compounds was very important in determining the amount of selection. Bialophos was found to be superior to pure phosphinothricin for in vitro selection. The commercial herbicide formulation was superior to pure phosphinothricin.; An electric discharge particle gun was constructed but was superseded by construction of a better helium discharge particle gun. Optimal gene gun parameters were tested with tobacco, cowpea, and soybean leaves. Optimal parameters for bombardment of soybean embryogenic suspension tissues were also determined. Expression of the soybean mosaic virus coat protein gene was demonstrated in bombarded tobacco leaves by enzyme-linked immunosorbent assay (ELISA).; Transformation attempts were made with the helium discharge particle gun. Two TN4-86 cultures were established that were resistant to hygromycin but were lost to contamination. Four TN4-86 plants were regenerated from one bombardment experiment and were tested by polymerase chain reaction (PCR) for the presence of the smv-cp and pat genes. The results were negative for their presence as were the results for a large number of bombarded embryos from the same experiment. Low transformation frequencies and low culture conversion frequency of embryos to plants contributed to the lack of success in these transformation experiments.