Vocabulary

greenhouse – теплиця, оранжерея

tender – тендітний, уразливий

suit – відповідати, підходити

diverse – різноманітний

orchid – орхідея

cactus ( мн. cacti) – кактус

frequently – часто

lean – нахиляти, спирати, спиратися

pane – панель

sloping – похилий

conventional – звичайний, стандартний

sufficient – достатній

supplement – додавати, поповнювати

spur – спонукати, стимулювати

whitewash – білити, вапнувати

reduce – скорочувати, зменшувати

derive - одержувати, здобувати

steam – пара

Vocabulary exercises

1. Practise the pronunciation of the following words:

plastic, suit, requirements, diverse, orchids, cacti, tomatoes, frequently, conventional, commercial, sufficient, artificial, spur, whitewashed, primarily, required

2. Find the stem in the following words; point out prefixes and suffixes. Translate the words into Ukrainian.

protection, requirements, frequently, existing, sloping, supporting, commercial, supplemental, ventilator, humidity, primarily, watering

Speech exercises

1. Describe a conventional greenhouse

Plant breeding

Introduction

Plant breeding is practical application of genetic principles to the development of improved strains of agricultural and horticultural crops. Plant breeders can adapt old crops to new areas and uses; increase yields; improve resistance to disease; enhance the nutritional quality and flavor of fruits and vegetables; and develop traits that are useful for storage, shipping, and processing of foods. Improved wheat and rice varieties sparked the green revolution in the developing world during the 1960s and '70s. In ornamental plants, breeders have developed larger and showier flowers, greater plant vigor, and myriad types, shapes, and colors.

Vocabulary

strain – риса; рід

yield – виробіток, вихід продукції

trait – характерна риса, особливість

processing – переробляння продуктів

vigor – сила, енергія

Vocabulary and speech exercises

1. In the text find the words which are derivatives of the following:

ornament, breed (2 words), great, horticulture, apply, use, genetics, ship, nutrition, develop (3 words), improve, store, agriculture, process, revolve, large, show.

Translate the words into Ukrainian.

2. Give the definition of plant breeding.

3. Answer the questions:

I. What benefits can plant breeding bring?

2. What plants sparked ‘the green revolution’ during the 1960s and ‘70s?

3. What strains of ornamental plants have been developed

HISTORY

Stone Age farmers improved crops through selection, choosing at each harvest the largest seeds from the best plants for sowing the following year. In so doing, over thousands of years, they converted favored wild grass and legume species into such crops as corn, wheat, and soya beans. In the 18th and 19th centuries farmers attempted to speed up crop improvement. Some advances were made, partly through selection and partly through trial and error, such as in the procedures used by the American horticulturist Luther Burbank. Through the work of Gregor Mendel, Hugo Marie de Vries, and others, the development of the science of genetics at the beginning of the 20^th century established a firm scientific base for plant breeding. Since that time it has continued to develop in both sophistication and accomplishments, enabling professional plant breeders to achieve predictable results and uniform quality.

Plant breeders use numerous methods to develop new varieties, but their primary techniques of development are selection, hybridization, and the use of mutations.

Vocabulary

legume – стручкова рослина

soya bean - соя

establish – встановлювати, створювати, засновувати

sophistication – вишуканість, витонченість, удосконалювання

Vocabulary and speech exercises

1. In the text find the words which are the derivatives of the following:

part, predict, try, horticulture, farm, profession, select, form, America, science, hybrid, accomplish, improve, able, err, mutate.

Translate the words into Ukrainian.

2. Answer the followind questions:

I. What was the first known method of improving crops?

2. How did breeders attempt to speed up crop improvement in the 18^th and 19^th centuries?

3. What outstanding plant breeders are mentioned in the article? Do you know more? Name them.

4. What are primary techniques of plant breeding nowadays?

SELECTION

Individuals within a species vary widely in a number of characteristics. Many of these traits are heritable and can be passed on to their progeny. In practicing selection, plant breeders choose plants with desirable traits for further propagation and discard plants that are inferior for that trait. By doing so, plant breeders can select and reselect for the trait through successive generations, shifting the population in the desired direction.

Vocabulary

progeny – нащадок, потомство

propagation – розмноження, розведення, відтворення

discard – позбуватися

inferior – гірший (за якістю)

successive – наступний

Vocabulary and speech exercises

1. In the text find the words which are the derivatives of the following:

wide, inherit, propagate, select, success, generate, populate, direct.

Translate the words into Ukrainian.

2 . Explain how selection works.

HYBRIDIZATION

Hybridization involves crossing plants of different strains or types to join in the progeny the desirable traits of both parents. Undesirable traits also enter the combination, however, so hybridization is usually followed by several generations of selection. This allows breeders to discard undesirable plants, choosing for further propagation only those plants with the desired combination of traits.

Backcrossing is a common variation on hybridization. This technique is often used to transfer into a desirable variety a beneficial trait from an otherwise undesirable parent. First the hybrid between the two parents is made; then the hybrid is crossed with the desirable parent. The progeny from this backcrossing normally segregate widely, with individual plants showing a mixture of the characteristics of both parents. By continued backcrossing and selection the plant breeder concentrates the qualities desired, and, if all goes well, in six or seven generations the variety once again breeds true but now exhibits its new trait. Backcrossing is valuable for adding single gene characteristics to crop plants, particularly for resistance to specific insects and diseases.

When desirable characteristics are fully developed in a hybrid plant, and the plant can be propagated asexually by budding, grafting, or cloning, then no further selection is necessary. A hybrid apple, for example, is propagated by grafting, so all resultant plants are identical.

Hybrids are often more vigorous than either parent. This phenomenon is called hybrid vigor and has been widely used by plant breeders to increase crop yields. Hybrid seeds have helped to double U.S. corn yields since the 1940s, and almost all the corn now grown in the United States and Europe is started annually from hybrid seed. Hybrid breeding has expanded in recent years, and hybrid varieties are now common in grain crops (corn, sorghum), vegetables (cabbage, tomatoes, squash), and many flower species.

Vocabulary

discard – відкидати

backcrossing – зворотнє схрещування

segregate – відокремлювати

budding – щеплення вічком

grafting – щеплення

vigorous – сильний, енергійний

expand – поширюватися, розширятися

squash – гарбуз; кабачок

sorghum – сорго

Vocabulary and speech exercises

1. In the text find the words which are the derivatives of the following:

hybrid, cross, differ, desire (3 words), combine, select, breed, vary (2 words), benefit, wide, value, sex, bud, graft, clone, identify, vigor.

Translate the words into Ukrainian.

2. Make a summary of the text in your own language.

MUTATION

Occasionally an individual plant shows an important change in one or more traits arising from a spontaneous mutation. Usually a change in a single gene is involved. Most mutations are deleterious, but occasionally one has a distinct advantage. The plant showing the mutation may be used directly as a variety, a common practice in apples and other fruits, or the new trait may be added to existing varieties through hybridization and backcrossing. Plant mutations caused by single-gene changes have found wide use in ornamentals, resulting in double-flowered forms, weeping stems, dwarfism or unusual growth habits, and a wide diversity of color variations. Mutations can be induced artificially by X- rays or ultraviolet light.

Doubling the number of chromosomes is another plant-breeding technique that has been useful in improving some flower and crop plants, sometimes producing forms with increased vigor and with larger leaves, flowers, and fruits. The chemical colchicine, an alkaloid extracted from the autumn crocus, is useful for this purpose.

Vocabulary

deleterious – шкідливий, небезпечний

ornamental – декоративна рослина

weeping – плакучий

diversity – різноманітність

induce – стимулювати, спонукати

Vocabulary and speech exercises

1. In the text find the words which are the derivatives of the following:

occasion, mutate, direct, dwarf, usual, diverse, artificial, use.

Translate the words into Ukrainian.

2. Answer the following questions:

1. Are all the mutations deleterious?

2. What kind of mutations can single-gene changes cause?

3. How do plant breeders induce mutations artificially?

4. What can doubling the number of chromosomes result in?

3. Summarise the text in four sentences.

NEW TECHNIQUES

Developments in plant tissue culture and genetic engineering are opening up new opportunities for plant breeders. In tissue culture, a single laboratory dish of plant cells can be the equivalent of a field with thousands of plants from which to select improved strains. As genetic engineering techniques are perfected, breeders may be able to transfer a gene for pest resistance to a crop plant directly from a wild relative or even from an unrelated species, thus reducing the need for pesticides over vast fields of crops. Such attempts were meeting with only quite limited success by the late 1980s, however, and genetic modification through somoclonal variation techniques may prove more immediately useful.

Vocabulary

tissue – тканина

opportunity – слушна нагода, сприятлива можливість

vast – великий, широкий, численний

Vocabulary and speech exercises

1. In the text find the words which are the derivatives of the following:

develop, resist, direct, relate (2 words), modify, immediate.

Translate the words into Ukrainian.

2. Answer the question:

I. What opens up new opportunities for plant breeders?