Screening of Glycine max and Glycine soja genotypes for multiple shoot formation at the cotyledonary node.

To identify genotypes which may give better plant regeneration responses in vitro, multiple shoots were induced from 155 Glycine max and 13 Glycine soja genotypes from maturity groups '000' to 'VII' on B5 medium supplemented with 1 or 5 μmol benzylaminopurine (BAP). The average number of shoots formed show genotype specific and hormone concentration specific responses, with number of shoots ranging from 1 to 12 for different genotypes. The results were reproducible with different seed lots of the same genotype and genotypes with similar genetic backgrounds responded in a similar fashion. No hybrid vigor was observed, except in one instance of F1 hybrids between low shoot producers where the number of shoots obtained were higher than either parent. The root forming ability of cuttings of soybean plants grown in vivo showed general agreement with shoot forming ability in vitro. The ability to form multiple shoots appears to be genetically controlled.