Callus formation per anther of highly recalcitrant rice genotypes increased from 6.3 to 20.6% when sucrose was replaced by maltose and AgNO3 was added to the induction medium (P = 0.01). The formation of green plants increased by 15 times when maltose in the induction medium was raised from 29 to 351 mM. On the other hand, glucose drastically reduced callus induction, and combinations of maltose and mannitol were less inductive than equiosmolal concentrations of maltose. No differences were noted when sucrose or maltose and silver nitrate were included in the regeneration medium, indicating that in rice anther culture the type of sugar and the anti-ethylene compound mainly affects callus induction and embryogenesis, but not plant development. These factors were investigated on diverse rice genotypes that represented a range of genetic diversity used in breeding. © 1995.