Этюды в области гибридизации, иммунитета и трансплантации растений

sterile (possessing one grain in some of the ears) and 79 ears were almost sterile- However, the studied pollen showed that the steri­ lity may be very often explained by destruction of the protoplast of the microspores by microbes. Segregation for other characters takes place much less. Degree and character of leaf pubescence dif­ fers sometimes very much. In some cases segregation for turges- cence of leaf plates is visible. The appearance of variegated leaf shoots and double ear shoots are rarely observed (fig. 6—7). : A ll the above mentioned phenomena are so rare that we are quite sure that by means of mass first and second selection we shall obtain a stable, a, so to say’ «good» species. General uniformity of the plant under sowing conditions; .genu­ ine grain and splendid germination, should be emphasized. The following experiments on the infection of Tr. fungicidum by parasitic fungi have been carried on. These experiments have pro­ ved the exceptional stability of the new species of wheat to Pucci­ nia grammes, Puccinia triticina, Puccinia glumarum, Ustilago tritici, Tilletia tritici and Erysiphe graminis f . tritici. Rust (Pucci­ nia) parasites frequent different hosts. One host is infected with a haploid mycelium, the other host by a diploid one. The diploid mycelium is capable of infecting wheat only, therefore we did not Operate with basidiospores. Infection of teleitospores .was also superfluous. It appeared that all the three above mentioned kinds of rust (Puccinia) can pass the winter in Moscow at the uredostage and, in this way, the infection method was greatly simplified. Therefore, we infected the wheat mainly with uredospores and sel­ dom with ecidiospores of Puccinia. Since Puccinia glumarum har­ dly affects wheat near Moscow, this parasite was cultivated on win­ ter wheat «Durable», very liable to this disease. The uredospores of Puccinia were collected in late autumn, after- cold nights, so that they were hardened for wintering. They were packed in parchment and placed into exciccators with calcium chloride at 1—5°. The germination capacity of the uredospores was preserved in this way till the spring. The wheat was infected during the vegetation period also with summer generations of uredospores. Besides, we attempted infection with ecidiospores of Puccinia graminis and Barberry leaves with newly opening ecidia were collected. Leaf sections with opened ecidia were carefully placed between humid leaf vaginae and stem internodia. Next, the plants were covered for several days with glass vessels. The germination capacity of the ecidiospores is preserved for a long time. A ll the experiments were carried out in hot and vegetation houses. Infection with uredospores was made with suspensions in warm pipe water. But as the Moscow water is chlorified, the suspension was kept for twenty four hours in large open glasses in order to eva­ porate the chlorine, inhibiting the germination of the spores. Sha­ king up the uredospores in water we sprinkled the plants with the suspension by means of ^pulverizers. Finally some of the plants — 41 - Электронная Научная Сельскохозяйственная Библиотека