Этюды в области гибридизации, иммунитета и трансплантации растений

However, only enlargement of non-ball like grain (as well as only ball-like shape without enlargement) cannot produce the same results as giving the grain a ball-like shape under conditions of maxi­ mum enlargement obtained any way. We carried on interspecific crossing of variously shaped grain from ecologically different wheat. Mother wheat—summer kind, from Gangue in India. Sire wheat — «Dvuruchka» ripens early when sowed in autumn, from mountainous Turkish Armenia. These speices belong to the 42-chromosome group of wheats. These species are on the whole close, but they are geographically remote, there­ fore, heterosis could be expected.. The F x hybrid is a summer species, semi-awned, completely fertile, of intermediary type, with, signs of general heterosis. In- spite of considerable segregation, the following generations of hyb­ rid females disclosed the following peculiarities: (1) stable general heterosis of all the characters in the majority of families till F 7 (outstanding facts, since as a rule it affects only F :); (2) complete fertility in all the progenital types; (3) relative reversion to the parental type, but on the basis of heterosis; (4) occurrence of new unknown hereditary varieties, belonging to the initial types; (5) absence of deformed types. The occurrence of inflate types should be noted which may be referred to the species Tr. comp actum, along with absence of square­ headed and speltoid forms. All this proves the peculiar character of inheritance in the given combination. The scope of the present paper does nt let us dwell on our hybri- dological studies. During six generations we selected for homozygo­ sity several valuable forms. The photographs of the ears and grain are instances of the families which are valuable in practical respect. Some of these types are by the tough thick straw, by the broad darkgreen leaves, large awned ear, large barrel-shaped grain. These are summer forms, with a short period till ear formation and so­ mewhat longer period lasting from earing till ripening (under con­ ditions of Moscow region). At the South, when sown in autumn, this is an expectionally fruitful and early ripening wheat species. This has been proved by test sowing in Samarkand. Other forms are distinguished by their ball-shaped grain. This is, evidently, the first pure bred wheat with relativelly large ball-shaped grain and very tough straw. In these forms the ballshaped type of the grain has been preduced along with an increase in size. The absolute weight (1000 grains) of the hybrids and of the stan­ dard amounts on the average to the following: of the barrel-shaped form 63.2 gr.; ball-shaped 49.31 gr.; Lutescence 062—40.5 gr. r. As compared with Lutescence 062, the hybrid-forms with barrel-shaped grain, are known for their yielding capacity and «rect stalk. The hybrid forms with ball-shaped grain do not droop at all. As compared with these hybrids, Lutescence 062 ripens ear­ lier but is less productive and droops. - 44 - Электронная Научная Сельскохозяйственная Библиотека