WHEAT (РАRT I)

Text А

Wheat is considered to have been the most important world cereal crop. The countries that lead in wheat produc­tion are the Soviet Union, the United States, China, Canada, India, France and Italy. Wheat ranks second as a cereal crop in the United States, being exceeded only by corn is acreage and in production.

Everybody knows wheat to have played an important role in the development of civilization from the earliest time. It is one of the principal sources of food for man and ani­mals. Wheat is believed to have originated in south-western Asia.

There exist different classifications of wheat varieti­es. The most common classifications of wheat are those ba­sed on the time of sowing, as spring ard winter wheati on the colour of the grain, as red and white wheat, on the

density of the grain, as hard and soft wheat; on the pro­ducts for which they are growe, as bread and macaroni wheat on the presence or absence of beards. As to winter wheat, it is usually preferred to spring wheat in regions where it will overwinter succesfully.

We know many new varieties of wheat to have been deve­loped, and among them lodge—resistant and shatter-resistant ones. Different cultivated varieties of wheat vary greatly in their habit, form and structure, but all are annuel grassee, that is, they require one season from sowing to pro­ducing seeds. Some important characteristics to consider in selecting a wheat varioty are. (a) time of maturity, (b) winter hardiness, (c) disease and insect resistance, (d) shattering and lodging, (e) quality and yield. Yield is usual­ly the main characteristic to be considered in choosing the variety to be grown.

Wheat is poorly adapted to warm or moist climates unless these is a comparatively cool dry season which favours plant growth and reduces the danger of diseases. She world wheat crop is grown in the temperate regions where the annua!9 rainfall averages between 10 to 70 inches, being mostly grown in regions having precipitation of 15 to 45 inches. High rainfall, especially when accompanied by high tempe­ratures, is unfavourable for wheat It results in lodging, affects harvesting, threshing, storing, sowing and soil preparation. The best quality bread wheats are producod in areas where winters are cold, summer comparatively hot and precipitation moderate.

In general there should he a frost-free period of about 100 days or more for" Safe wheat production. Quick-maturing varieties may be grown where the frost-free period is 90 days or less and where long days hasten flowering.

Дата добавления: 2015-03-31