Disadvantages of Artificial Vegetative Propagation
- Cutting is to cut stem from a plant and replanting it. Example: grapes, pineapple.
- Grafting is to attach a part of plant to the base of another plant. It is mostly done in citrus plants and may be done in other plants also. It is important that plants involved in the graft process must be similar in their species.
- Tissue culture is the growth of new offspring in a medium of culture that contains all substances necessary for growth. This method is carried out in sterile laboratory conditions.
- The plants do not have genetic variation and lose their vigor gradually.
- There are more prone to diseases specific to the species which can result in the destruction of the entire crop.
- As many plants are produced, it may result in overcrowding and lack of nutrients.
- It can induce overcrowding.
- As there is no genetic variation, the offspring are less adaptable to the environment.
- If the parent has a disease all the offspring inherit the disease.
- Plants that are air layered and cut plants generally do not have a strong root system
- These plants may collapse in certain age.
- In artificial vegetative propagation only few new individual plants are produced from a parent plant.
- The parent plant will be burdened if they are air layered too much.
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Plant propagation is the process of creating new plants from a variety of sources: seeds, cuttings, bulbs and other plant parts. Plant propagation can also refer to the artificial or natural dispersal of plants.
Sexual propagation (seed)
Seeds and spores can be used for reproduction (through e.g. sowing). Seeds are typically produced from sexual reproduction within a species, because genetic recombination has occurred plants grown from seeds may have different characteristics from its parents. Some species produce seeds that require special conditions to germinate, such as cold treatment. The seeds of many Australian plants and plants from southern Africa and the American west require smoke or fire to germinate. Some plant species, including many trees do not produce seeds until they reach maturity, which may take many years. Seeds can be difficult to acquire and some plants do not produce seed at all.
Commonly used by both hobby gardeners, and in large scale industrial facilities, an electrical propagator is a low-cost, efficient and safe method of encouraging seed growth.
Plants have a number of mechanisms for asexual or vegetative reproduction. Some of these have been taken advantage of by horticulturists and gardeners to multiply or clone plants rapidly. People also use methods that plants do not use, such as tissue culture and grafting. Plants are produced using material from a single parent and as such there is no exchange of genetic material, therefore vegetative propagation methods almost always produce plants that are identical to the parent. Vegetative reproduction uses plants parts such as roots, stems and leaves. In some plants seeds can be produced without fertilization and the seeds contain only the genetic material of the parent plant. Therefore, propagation via asexual seeds or apomixis is asexual reproduction but not vegetative propagation.
Techniques for vegetative propagation include:
- Air or ground layering
- Grafting and bud grafting, widely used in fruit tree propagation
- Stolons or runners
- Storage organs such as bulbs, corms, tubers and rhizomes
- Striking or cuttings
This can be in the form of a clear enclosed bin sitting over a hotpad, or even a portable heater pointed at the bin. the key is to keep the moisture in the clear bin, while keeping lighting over the top of it, usually
Seed propagation mat
An electricseed-propagation mat is a heated rubber mat covered by a metal cage which is used in gardening. The mats are made so that planters containing seedlings can be placed on top of the metal cage without the risk of starting a fire. In extreme cold, gardeners place a loose plastic cover over the planters/mats which creates a sort of miniature greenhouse. The constant and predictable heat allows people to garden in the winter months when the weather is generally too cold for seedlings to survive naturally. When combined with a lighting system, many plants can be grown indoors using these mats.
The history of agriculture (the production of food by plant cultivation and animal husbandry and control of productivity) can be organized around several themes (such as time, productivity, environmental impact, and genetic diversity). The most obvious is time and the sequence of events from gathering wild plants for food to crop plant domestication , to yield-enhanced hybrid seed. The origin of agriculture was around ten thousand years ago or approximately four hundred human generations back in time and prehistory, before written records were kept. What is known is based on evidence gathered from archaeological sites. Agriculture started independently in at least three places in the world, each with a distinctive cluster of plants drawn from the local flora: Mesoamerica (Mexico/Guatemala: corn, beans, squash, papaya, tomatoes, chili, peppers), the Fertile Crescent (Middle East from the Nile Valley to the Tigris and Euphrates Rivers: wheat, barley, grapes, apples, figs, melons, lentils, dates), and north China (mid-reaches of the three-thousand-mile-long Yellow River: rice, soybeans, peaches, Chinese cabbages such as bok choy). From these regions and possibly others, notably Africa (sorghum, cowpeas, yams, oil palm), South America (potatoes, sweet potatoes, cassava, peanuts, pineapples), and a broad band of tropical southeast Asia (oranges, mangoes, bananas, coconuts, sugarcane), the invention of agricultures spread to encompass the entire world by two thousand years ago. The history of agriculture is not that of a single technology to produce food, but of an array of methodologies. Planting seed broadcast across plowed fields typifies most cereals (50 percent of human calories). Vegetables, legumes , and corn are planted from seed in rows separated by furrows. Seed agriculture usually consists of annuals that are typically planted as genetically uniform monocultures . Agriculture of the humid tropics has been more vegeculture than seed-based. These vegetatively propagated crops are usually perennials, productive over the entire year and found in polycultures that tend to mimic the forest ecosystem . The earliest agriculture of southeast Asia was typically based on roots and tubers such as yams and taro, tree crops such as coconut and banana, and perennials such as sugarcane. In the Americas, vegeculture developed with cassava, sweet potatoes, arrowroot, and peanuts, and moved up the eastern slopes of the Andes, ultimately domesticating the potato. These crops spread quickly throughout the world after European contact. Potatoes displaced wheat and barley in cold soils of northern Europe and bananas became the fruit of choice in the New World tropics. Seed agriculture dominates where either a pronounced dry season or a frost results in a single crop per year. In south China rice is the summer crop, sweet potato the winter crop. In India rice is the monsoon crop, wheat the winter crop. Sometimes intercropping (different crops in alternate rows) and relay planting (starting the next crop before the previous one is harvested) are part of the multiple-crops-per-year cycle. Sequential cropping is where one crop follows another without seasonal fallowing, sometimes in double-cropping but more often in triple-cropping. Fallowing is an important technology perfected in the Middle Ages as part of the crop rotation pattern. The first year a legume is planted and the soil is enriched by the nitrogen-fixing crop; the next year a cereal is planted. The third year the land is rested to regain soil moisture and restore soil health. This pattern approximates a natural ecosystem and is more sustainable over the long term than continuous cropping. The fallow crop rotation system maximizes resources but is not elastic enough to accommodate an increasing human population that has come to rely on continuous cropping or heavy use of inputs (such as fertilizer, pesticides, and irrigation) in single crop per year monocultures. Another theme is to measure the displacement of natural ecosystems of forest and grasslands by plowed cropland that supports an increasing human population. Only about five million people existed worldwide preagriculture, subsisting on hunting and gathering of wild animals and plants. Humans existed like any other wild animals in the biological world. Postagriculture, the human population grew slowly, but as people's mastery of food production technology developed (such as irrigation, weed control by hoe and plow, and planting crops in monocultures) and the number of crop plants increased, the world population climbed to an estimated 130 million people by the time of Christ, a twenty-five-fold increase from the Paleolithic pre-agriculture estimate. By 1650 the world population had reached a half billion, and half of these people were in settled urbanized villages, towns, and cities and not engaged in agriculture to produce their own food. All of the major food crops and domestic farm animals known today were known and used worldwide. The only significant crops added since 1650 are industrial crops such as rubber. Since the middle of the nineteenth century the population has increased from one billion to six billion, an increase that would not have been possible without increases in agricultural yields. Through breeding, plus the use of fossil fuels to plant, fertilize, and protect crops, the average yield of all plants and productivity per unit area has increased ten-to fiftyfold. At present humans produce and consume over a twenty-year period as much food as was produced in the eight thousand years between the development of agriculture and the sixteenth century. Nonetheless, of the six billion people in the world, over one billion are estimated to be malnourished, and half of these are seriously underfed, mostly due to poverty and the diminished affordability of agricultural products. An estimated fifty thousand to eighty thousand starve to death or are fatally compromised each dayâ€”a majority are children, in part because they are growing rapidly and do not get enough essential materials such as vitamin A or quality protein. Another theme is to realize how few crops currently feed the human population, considering that preagriculture humankind subsisted on a list of approximately five thousand wild edible plants. The agricultural crop list is short. One-half of the plant calories people consume come from three grasses: rice, wheat, and corn. Just over two dozen food plants account for 75 percent of all plant calories and 90 percent of arable land cultivated. This list includes six grasses: rice, wheat, corn, barley, oats, and sorghum; four legumes: soybeans, peanuts, common beans, and peas; two sugar crops: sugarcane and sugar beets; two tropical tree crops: bananas and coconuts; four starchy roots: potatoes, sweet potatoes, cassava, and yams; five fruits: tomatoes, grapes, apples, oranges, and mangoes; and two vegetables: cabbages and onions. These twenty-five crops literally stand between subsistence and starvation for the human population. This is an agricultural calorie list and does not recognize the extremely rich vitamin and mineral sources found in low-calorie vegetables and fruits. Also this list does not recognize the important regional foods of the world. For instance, the native American crop cranberries is extremely important to Americans at Thanksgiving but is insignificant on the world calorie chart (less than one-millionth of 1 percent). A dominant theme in the history of agriculture has been crop improvement and yield advancement through selection and exploitation of genetic diversity within the species and its close relatives. And now, there is bioengineering where a gene can come from anywhere in the biological world (genetically modified crops). The earliest stages of domesticated crops were probably not much more productive than the wild progenitors , but the act of cultivation and saving the seed to replant was a radical break with the past. Human selection (artificial selection) was replacing natural selection in shaping the plant. Traits associated with the domestication process are seeds and fruits that remain
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Answers:vegetative propagation, the ability of plants to reproduce without sexual reproduction, by producing new plants from existing vegetative structures. Some plants, such as the Canada thistle and most bamboos, send out long underground stems that produce new plants, often at considerable distances from the original plant. Such plants can form enormous colonies of new plants within a relatively few years. Many trees, such as the beech and aspen, send up root sprouts, and large colonies of new trees thus arise. In other trees, the lower branches may produce roots where they rest upon the ground, and new trees are produced. The leaves of some plants produce buds at their edges, which develop in turn into miniature plants that fall off and take root. Specialists in the fields of agriculture and horticulture take advantage of the regenerative ability of plants through such techniques as the rooting of cuttings; grafting and budding of fruit trees; layering, or inducing the tips of branches to produce new plants; the cutting apart of clusters of perennials perennial, any plant that under natural conditions lives for several to many growing seasons, as contrasted to an annual or a biennial. Botanically, the term perennial Advantages and Disadvantages of Vegetative Propagation Advantages The offsprings are genetically identical and therefore advantageous traits can be preserved. Only one parent is required which eliminates the need for special mechanisms such as pollination, etc. It is faster. For example, bacteria can multiply every 20 minutes. This helps the organisms to increase in number at a rapid rate that balances the loss in number due to various causes. Many plants are able to tide over unfavourable conditions. This is because of the presence of organs of asexual reproduction like the tubers, corm, bulbs, etc. Vegetative propagation is especially beneficial to the agriculturists and horticulturists. They can raise crops like bananas, sugarcane, potato, etc that do not produce viable seeds. The seedless varieties of fruits are also a result of vegetative propagation. The modern technique of tissue culture can be used to grow virus-free plants. Disadvantages The plants gradually lose their vigour as there is no genetic variation. They are more prone to diseases that are specific to the species. This can result in the destruction of an entire crop. Since many plants are produced, it results in overcrowding and lack of nutrients.
Answers:I am a nutrition major so I mostly eat organic food. The benefits of organic foods: Organic farming lowers water pollution and builds soil fertility. By eating organic food, you cut down on the chemical load that you take in, as it contains no insecticides, pesticides, growth hormones, antibiotics, fertilisers and toxic artificial additives, flavourings, colourings and preservatives. The food reaches you in a natural state with its nutrient content intact. Organic food is often fresher than non-organic food, because it has no preservatives so it is rushed straight to the shops. Natural food has more flavour The downside They are more expensive. Organic produce must be thoroughly washed because it may be contaminated by improperly composted animal fertiliser. Organic products are also not always available. This is because organic farmers rely entirely on natural cycles. Floods, droughts and pest infestations can ruin the entire crop. Conventional farmers can artificially extend the natural seasonality of their fruits and vegetables, so that you get oranges in summer and avocado pears all year round. Also.....I recommend buying the book...."The Organic Food Guide" by Steve Meyerowitz....teaches you all about the benefits!
Answers:These are probably Geographically based reasons, but still: Advantages of Intensive Farming One of the major advantages of intensive farming is that its yield is high. With the introduction of intensive farming, the farm produce such as vegetables, fruits and poultry products have become less expensive. This means that poor people can afford a balanced and nutritious diet. Many opine, organic food is affordable only to the rich and the elite strata of the society. Apart from that, large farming spaces are required to cultivate organic crops using natural manure. However, with the introduction of intensive farming, the space requirement for farming is less. Another advantage of intensive farming is that large productivity of food is possible with less amount of land. This would help to meet the ever-growing demand for food supplies. Compared to the disadvantages, the advantages of intensive farming are less. Disadvantages of Intensive Farming Remember, intensive farming involves the usage of various kinds of chemical fertilizers, pesticides and insecticides. Apart from this, intensive farming is also associated with farms that keep livestock above their holding capacity and this could lead to pollution and various diseases. Reports and studies reveal intensive farming affects and alters the environment in multiple ways. Forests are destroyed to create large open fields and this could lead to soil erosion. Intensive farming affects the natural habitats in the forests. Use of chemical fertilizers contaminates water bodies such as lakes and rivers near the farming land. The pesticides sprayed on crops not only destroy pests and contaminate the crops but also kill good insects. Eventually, these chemicals are passed on to the human beings. The fruits and vegetables bought from farms that promote intensive farming are covered with invisible pesticide. These are not easily washed off. The residue of the pesticide affect the health of human beings. The statistics show, an increase in the number of cancer patients. Researchers opine, consumption of inorganic vegetables, fruits, poultry and meat could probably be one of the reasons. There are many hybrid varieties of livestock and poultry today. The livestock and poultry are injected with hormones and other chemicals to increase the yield. There is a tug of war between the animal rights activist and farmers of intensive farming. However, the debate is still on going without much success. There are both pros and cons in promoting intensive farming. Intensive farming involves genetic selection and breeding of both plants and animals. Artificial growth hormones and inorganic plant nutrients are mixed with the fertilizers and livestock feed. This results in the highest yield of all time. On one side, the health of human beings is largely affected by intensive farming, while on the other side, it is argued that the poor and needy cannot simply afford organic food.
Answers:Plants reproduce sexually by seeds, and asexually by vegetative propagation such as runners, suckers, bulblets, etc. Artificial propagations by tissue culture, cuttings, air-layering, etc. are asexual reproduction.