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Find the paragraph in the text describing the methods of plant improvement.



Discuss it in English.

1)what is selection? Describe this method of plant improvement.

2)what are the principles of plant improvement?

3) how many introductions of wheat have been made in the United States?

Write an annotation on textsA and В.

Translate the text using a dictionary.

 

Text C

Selection is not a new method of improving plants. Actually this process is as old as plants themselves. For many thousands of years plants have been subjected to forces of nature, and only the fittest have been able to survive. However, when selection is left entirely to nature, the process is extremely slow. Man cannot wait for nature alone to improve plants for him. By selecting superior plants, he is able to bring about improvement in a few years that would require thousands of years if left to nature alone.

Selection is also used along with other procedures such as inbreeding and crossing in developing new varieties. In fact it is a basic part of all work in the field of plant breeding.

Two procedures are commonly used when new varieties are developed by the process of selection.

These procedures are referred to as mass selection and individual plant selection.

Mass selection. This method consists of selecting a fairly large number of individual plants possessing the desired characteristics. The seed from such plants is then mixed and sown together, and the better individuals are again selected or the poorer ones discarded, whichever is most convenient. This process of selection is to be repeated for a few years until the plants prove to be reasonably uniform for the qualities desired. Selection of open-pollinated corn for seed, a practice, which was common for many years before the appearance of hybrid corn, is an example of mass selection. The principle of mass selection was first applied to corn in about 1850 and played an important part in the early improvement of corn. The procedure of mass selection, as it relates to plant improvement, is most commonly applied to plants that are largely naturally cross or open-pollinated.

Unit 10

Soil

Pretext Exercises

Name the Russian equivalents of these international words.

structure, structural, structurally, structureless

proportion, disproportion

aggregate, aggregated, segregation

erosion, erosive

normal, normally, normalization

adequate, adequately, inadequate

chemical, chemically, chemist

deficit, deficient

absorption, absorb, absorbing, absorbed

aeration, aerator

 

Identify the parts of speech these words belong to.

essential, texture, sandy, usually, greatly, cultivation, erosion, aggregated, organic, moisture, sufficient, insufficient, ordinary, necessary, oxidation, considerable, available, growth, fertilizer, favourable

Vocabulary list.

1. heavy soil – тяжелая почва

2. light soil – легкая почва

3. clay loam – глинистая почва

4. sandy soil – песчаная почва

5. acid soil – кислая почва

6. alkaline soil – щелочная почва

7. fine soil – мелкоструктурная почва

8. particle – частица

9. organic matter – органическое вещество

10. prepare – готовить

11. quantity – количество

12. in order to – для того чтобы

13. loam soil – суглинистая почва

14. volume – объем

15. toarrange – располагаться, устраивать (ся)

16. erosion – эрозия

17. constituent – составная часть

18. coarse – грубый крупнозернистый

19. moist – влажный

20. oxidation – окисление

21. hydrogen – водород

22. abundant – обильный, изобильный

23. water-holding capacity – влагоемкость

24. provided – при условии

25. richin – с высоким содержанием

26. tomeettheneeds– удовлетворять потребности

 







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