Domestication of crop plants: Process, Importance & Effects

Plant breeding in certain situations may lead to the domestication of wild plants. Domestication of crop plants is an artificial selection process conducted by humans to produce plants that have more desirable traits than wild plants, and which renders them dependent on artificial environments for their continued existence.

What is plant domestication?

The process of bringing wild plants under human management is referred to as plant domestication. Domesticated plants are grown on farms and become dependent upon humans for propagation. Domestication changes the physical characteristics of the plants under human management.

Purpose of domestication:

The man has brought wild plants under his control for various purposes. Plants have been domesticated primarily for five main purposes, viz. food, clothes, and shelter, medicines, and aesthetic value. These are briefly discussed below:

 1. Food:

Those plants which are domesticated for large-scale food production are generally called crops. Such plants include food grains, vegetables, and fruit crops. 

2. Clothes:

Those plants which are domesticated for large-scale cloth production are referred to as fiber crops. Such plants include cotton, jute, sun hemp, kenaf, and other fiber-yielding plants.

3. Shelter:

Those plants which are domesticated for large-scale wood production are referred to as timber trees. Such plants are grown in houses for windows, doors, and furniture.

4. Medicines:

Those plants which are domesticated for large-scale medicine production are called medicinal plants. These plants are used for the treatment of various human and animal diseases.

5. Aesthetic:

Those plants which are domesticated for decoration purposes are referred to as ornamental plants. Such plants are grown in and around the home and are usually called house plants or ornamentals. There is a long list of ornamental plants which beyond the scope of this discussion.

Process of domestication:

It is generally believed that three main factors, viz, (i) natural selection, (ii) spontaneous mutations, and (iii) carefully controlled selective breeding is responsible for many of the

collective changes associated with domestication. These factors are not mutually exclusive and it is likely that natural selection and selective breeding have both played some role in the processes of domestication throughout history.

The domestication of wheat provides an example of how natural selection and mutation can play a key role in the process, Wild wheat falls to the ground to reseed itself when it is ripe, but domesticated wheat stays on the stem when it is ripe. 

There is evidence that this critical change came about as a result of a random mutation near the beginning of wheat cultivation. Wheat with this mutation was the only wheat harvested and became the seed for the next crop. 

This wheat was much more useful to farmers and became the basis for the various strains of domesticated wheat that have since been developed. The example of wheat has led some to speculate that mutations may have been the basis for other early instances of domestication of crop plants.

Effects of domestication:

Various plant characteristics have been modified under domestication in relation to their usefulness to humans. The major effects of the domestication of crop plants include:

1. Higher germination rates

2. Greater germination predictability 

3. More uniform timing of germination

4. Increased size of reproductive organs

5. Reduced complexity of reproductive organs

6. Reduction of toxicity (humans select against self-defense mechanisms)

7. Change in biomass allocation (more in fruits, roots, or stems, depending on human preference) 

8. Change in the life cycle (normally from perennial to annual for seed crops, and from annual to biennial for vegetable crops)

9. Change in quality of produce in terms of color, taste, texture, and odor. 

10. Improvement in the productivity of the economic plant part.

Limitations:

The main limitations of the domestication of crop plants are listed below.

 1. Domestication is a very slow process. It takes hundreds of years to bring a wild plant under domestication.

 2. Wild plants have several undesirable traits. Elimination of such traits requires continuous breeding efforts.

 3. Domestication leads to a reduction in the resistance of plants to biotic and abiotic stresses. In other words, domesticated plants are less resistant to biotic and abiotic stresses than their wild counterparts.

 4. Domestication makes the plants human dependent for their reproduction.

In case you missed it: Objectives Of Plant Breeding-Definition-History And Scope

Achievement of plant domestication:

A large number of agricultural, horticultural, and medicinal plants have been domesticated by humans since the beginning of civilization. Crop plants include a long list of food, vegetables, oilseeds, pulses, fodders, fiber, and sugar-yielding crops. Similarly, horticultural crops include fruit crops, vegetable crops, and ornamental plants. However, the place and date of domestication are available only for very few plant species. The list of some domesticated crop plants is given below:

I. Agricultural Crop Plants

 1. Cereal Crops: This group includes wheat, barley, rice, pearl millet, sorghum, maize, oats, rye, foxtail millet, finger millet, triticale, amaranth, etc.

 2. Pulse Crops: This group includes pigeon pea, chickpea, mung bean, urd bean, co pea, field pea lentil, soybean, common bean, Lathyrus, horse gram, etc.

 3. Oilseed Crops: This group includes mustard, rapeseed, linseed, castor, sesame, ground nut, soybean, sunflower, safflower, niger, etc.

 4. Fibre Crops: This group includes cotton, jute, hemp, kenaf, flax, etc. 

5. Sugar Crops: There are two major sugar-yielding crops, viz, sugarcane and sugar beet

 6. Fodder Crops: This group includes sorghum, pearl millet, fodder maize, cowpea Lucerne, alfalfa, cluster bean, rye, oats, Napier grass, horse gram, and many other crops.

II. Horticultural Crops

There is a long list of horticultural plants which have been domesticated. The horticultural crops are of three types, viz. fruit crops, vegetable crops, and flowering plants. These are listed below.

1. Fruit Crop: This group includes apples, pears, plums, peaches, cherries, and strawberries. mango, guava, litchi, loquat, banana, grapes, pomegranate, fig, jackfruit, papaya, lime, lemon. oranges, grapefruit; dry fruits such as almonds, cashew, chestnut, walnut, and many other fruit crops.

2. Vegetable crops: This group includes potatoes, onions, garlic, cabbage, and cauliflower. knolkhol, radish, turnip, carrot, pepper, tomato, brinjal, bottle gourd, sponge gourd, bitter gourd, spinach, okra, cucumber, and many other crops.

3. Flowering Plants: This group includes several annual, biennial, and perennial [tree] flowering plants.

III. Medicinal Plants

This group includes belladonna, cacao, cannabis, coffee, cola, opium poppy, quinine, tea, tobacco, etc.

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 Conclusion

Plant domestication is the process by which humans have brought wild plants under their control for various purposes, such as food, clothing, shelter, medicine, and aesthetic value. Domesticated plants become dependent on humans for propagation, and their physical characteristics change under human management. 

The process of domestication of crop plants is believed to involve natural selection, spontaneous mutations, and selective breeding, which have collectively led to modifications in plant characteristics useful to humans, such as higher germination rates, increased size of reproductive organs, and changes in biomass allocation.