were evaluated. Additional ingredients, including KH2PO4, CuSO4·5H2O, L-asparagine, L-proline and
polyvinylpyrrolidone (PVP) were also assessed. Results showed that callus age had a conspicuous effect on
its growth and regenerability, with callus weekly growth ratio and regenerability peaked at two weeks after
induction. A callus induction rate up to 100% was achieved in inbred line Tx430, whereas regeneration rates up
to 100% were obtained from SA281 and 91419R. This highly efficient system has been utilized for sorghum
transformation for several years and has been proven to be reliable and reproducible.