A reformulation of Murashige and Skoog medium (WPBS medium) improves embryogenesis, morphogenesis and transformation efficiency in temperate and tropical grasses and cereals.

Slow callus growth is a barrier to efficient genetic transformation in some gramineous species. A reformulation of Murashige and Skoog (MS) medium, with additional magnesium sulphate, potassium phosphate, copper sulphate, proline and glutamine, termed WPBS medium, has been developed which improves all aspects of in vitro culture when compared with MS based media. Embryogenic callus could be produced more rapidly from responsive genotypes of sixteen cereal, forage, model and energy grass species, whether using embryos, shoot tips or proliferated meristems as explants. Three species were not transformed due to contamination or unsuitable explant, but thirteen species were transformed using an identical -mediated transformation, selection and regeneration protocol, including and . Readily transformable species such as , and and recalcitrant species such as and were reliably transformed, while two new species and viviparous were transformed at the first attempt. It is hoped that the use of WPBS media and this general transformation protocol may help to improve the efficiency of grass and cereal transformation.