A tissue culture system for different germplasms of indica rice.

Agrobacterium-mediated transformation of indica rice has been manipulated in only a limited number of cultivars because the majority of indica varieties are recalcitrant to in vitro response. Establishment of a highly efficient and widely used tissue culture system for indica rice will accelerate the application of transformation technology in breeding programs and the study of the functions of indica-specific genes. By manipulating plant growth regulators, organic components and salts within the culture media, we established two media for callus induction and subculture, respectively, in tissue culture of indica rice. The modified media could guarantee the production and proliferation of a great number of embryogenic calli with high regeneration capacity from mature seeds representing different indica rice germplasms. The calli obtained from this system should be ideal material for Agrobacterium-mediated transformation. The results suggest that this optimized tissue culture system will be widely applicable for the tissue culture of indica varieties.