Abstract
Abstract A multistep in vitro cell selection was carried out on a well-proliferating callus tissue of sugar beet capable of morphogenesis. A 20-day culture filtrate of the fungus Fusarium oxysporum was used as a selective agent. The general features of the behavior of sugar beet callus cells cultivated under stress conditions on increasing concentrations of the culture filtrate, 5, 10, 15, and 20%, have been established. It was found that a low concentration of CF (culture filtrate) of the pathogen (5%) significantly stimulated the process of callusogenesis, while high concentrations (10–20%) had an inhibitory effect. As a result of cell and tissue selection, calluses that retained the ability for normal growth in the presence of sublethal concentrations of the selective agent were selected. By the method of multistep selection, 82 callus lines characterized by resistance to the toxic effects of CF were selected. From selected callus lines, 47 regenerated plants adapted to the soil were obtained. Only 24 plants passed the test for resistance to the fungus Fusarium oxysporum under in vivo conditions.