Establishment of fine suspension cultures of Triticum tauschii ([Coss.] Schmal.) which remain embryogenic for several years

Immature embryos of 10 accessions of Triticum tauschii, the D genome donor of Triticum aestivum, were used to produce embryogenic callus for the initi ation of suspension cultures. For the long-term maintenance of embryogenici ty of these suspensions, it was necessary to use different media for the in itiation, establishment and maintenance phases. The initiation phase requir ed media supplemented with L-proline, L-asparagine and L-glutamine, togethe r with Dicamba at 12 mg L-1 and maltose. In the establishment phase, it was essential to reduce the concentration of Dicamba to 6 mg L-1 for the rapid production of fine suspension cultures. Finally, the long-term maintenance of a capacity for regeneration depended on the inclusion of 1.1 mg L-1 2,4 -dichlorophenoxyacetic acid and 30 g L-1 sucrose in the medium. By the use of these procedures, long-term embryogenic fine suspension cultures were es tablished from two accessions, while non-embryogenic fine suspension cultur es were produced from five accessions. Over 90% of plants regenerated from fine suspensions of 1-year-old embryogenic cultures were fertile, and embry ogenic suspension cultures retained their regeneration capacity for more th an 3 years.