What are the benefits of Sharbati wheat

Mutation breeding - Mutation breeding

Mutation breeding , sometimes called " Variation breeding "Denotes the process of exposing seeds to chemicals or radiation to create mutants with desirable traits to be bred with other strains. Plants created by mutagenesis are sometimes referred to as mutagenic plants or mutagenic seeds. More than 3200 mutagenic plant varieties, derived either as direct mutants (70%) or from their offspring (30%), were released from 1930 to 2014. Crops account for 75% of the released mutagenic species, the remaining 25% for ornamentals or ornamentals Although the FAO / IAEA reported in 2014 that over 1,000 mutant varieties of major staple foods were grown worldwide, it is unclear how many of these varieties are currently used in agriculture or horticulture worldwide as these seeds are not always identified or as mutagenic marked.

process

There are different types of mutagenic breeding, for example the use of chemical mutagens such as ethyl methanesulfonate and dimethyl sulfate, radiation or transposons to generate mutants. Mutational breeding is commonly used to create traits in cultures such as larger seeds, new colors, or sweeter fruits that either cannot be found in nature or have been lost during evolution.

Radiation breeding

Exposing plants to radiation is sometimes referred to as radiation breeding and is a subclass of mutagenic breeding. Radiation breeding was discovered in the 1920s when Lewis Stadler of the University of Missouri used X-rays on corn and barley. In the case of barley, the resulting plants were white, yellow, light yellow, and some had white streaks. In 1928 Stadler published his results on radiation-induced mutagenesis in plants for the first time. During the period 1930-2004, radiation-induced mutant strains were developed primarily using gamma rays (64%) and X-rays (22%).

Radiation breeding can take place in atomic gardens; and seeds were put into orbit to expose them to more cosmic rays.

Use of chemical mutagens

Because of the high rate of chromosomal aberrations due to ionizing radiation and the associated adverse effects, researchers looked for alternative sources for inducing mutations. As a result, a number of chemical mutagens were discovered. The most commonly used chemical mutagens are alkylating agents. Ethyl methanesulfonate (EMS) is the most popular due to its effectiveness and ease of use, especially its detoxification by hydrolysis for disposal. Nitroso compounds are the other widely used alkylating agents, but they are photosensitive and due to their higher volatility, additional precautions must be taken. EMS has become a widely used mutagen for developing large numbers of mutants for screening, for example for developing TILLING populations. Although many chemicals are mutagens, few have been used in practical breeding because the doses need to be optimized and also because the potency in plants is not high for many.

history

According to garden historian Paige Johnson

After the Second World War there were concerted efforts to find a “peaceful” use of atomic energy. One of the ideas was to bombard plants with radiation and produce lots of mutations, some of which would hopefully result in plants that were heavier weight bearing, disease resistant, cold resistant, or just unusual colors. The experiments were carried out mainly in huge gamma gardens on the grounds of national laboratories in the USA, but also in Europe and in countries of the former USSR.

Comparison with other agronomic techniques

In the debate about genetically modified foods, the use of transgenic processes is often compared and contrasted with mutagenic processes. While the abundance and variation of transgenic organisms in human food systems and their effects on agricultural biodiversity, ecosystem health, and human health are reasonably well documented, mutagenic plants and their role in human food systems are less well known, one journalist wrote : "Although little-known radiation breeding has produced thousands of useful mutants and a sizeable portion of the world's crops ... including rice, wheat, barley, pears, peas, cotton, peppermint, sunflowers, peanuts, grapefruit, sesame seeds, bananas and cassava and sorghum . "In Canada, plants produced by mutational breeding are subject to the same regulations and tests as plants produced by genetic engineering. Mutagenic varieties are typically made freely available for plant breeding, as opposed to many commercial plant varieties or germplasm whose use is increasingly restricted, such as terms of use, patents, and proposed technologies to restrict genetic users, and other intellectual property regulations and enforcement modalities.

In contrast to genetically modified plants, in which one or two target genes are typically inserted, plants that were developed via mutagenic processes with random, multiple and unspecific genetic changes were discussed as questionable, but are not prohibited according to the organic standards of a country . According to reports from the US National Academy of Sciences, there is no scientific justification for regulating genetically modified plants, while there is not for mutation-breeding plants.

Several organic food and seed companies promote and sell certified organic products developed using both chemical and nuclear mutagenesis. Several certified organic brands, whose companies support strict labeling or a downright ban on GMO plants, market their use of branded wheat and other varietal strains that come from mutagenic processes without reference to this genetic manipulation. These organic products range from mutagenic barley and wheat ingredients used in organic beers to mutagenic grapefruit varieties that are sold directly to consumers as organic products.

New mutagenic techniques

Restriction endonucleases

Interest in the use of bacterial restriction endonucleases (RE) to study double-stranded breaks in plant DNA began in the mid-1990s. It has been found that these DNA breaks, also known as DSBs, are the cause of a lot of chromosome damage in eukaryotes that cause mutations in plant varieties. REs induce a similar result on plant DNA as ionizing radiation or radiomimetic chemicals. It has been found that blunt breaks in DNA, as opposed to sticky breaks, produce more variations in chromosome damage, making them the more useful type of breaks for mutation breeding. While the link of REs to chromosomal aberrations is mostly limited to research on mammalian DNA, success in mammalian studies has caused scientists to limit more studies of RE-induced chromosomal DNA and lead to damaged genomes on barley. Because of the ability of restriction endonucleases to facilitate damage in chromosomes and DNA, REs can be used as a new method of mutagenesis to promote the proliferation of mutated plant varieties.

Space breeding

The ability of plants to develop and thrive depends on conditions such as weightlessness and cosmic rays in space. China has experimented with this theory by sending seeds into space to test whether space flights cause genetic mutations. Since 1987, China has cultivated 66 mutant strains from space as part of its space breeding program. Chromosomal aberrations increased sharply when seeds were sent to the aerospace industry when compared to their terrestrial counterparts. The impact of space travel on seeds depends on their type and variety. For example, space-grown wheat experienced high growth in seed germination compared to its terrestrial control, but space-grown rice had no apparent advantage over its control. In the case of the varieties that were positively mutated by space travel, their growth potential exceeded not only that of their counterparts grown on earth, but also of their irradiated counterparts on earth. Compared to conventional mutagenic techniques, room-grown mutations are more effective in that they have positive effects on their first generation of mutations, while irradiated plants often do not see beneficial mutations in their first generation. Although several experiments have shown the beneficial effects of space travel on the seed mutation, there is no clear link as to which aspect of aerospace created such beneficial mutations. There is much speculation that cosmic rays are the source of chromosomal aberrations, but so far there has been no concrete evidence of such a link. Although China's space breeding program has proven very successful, the program requires a large budget and technological support that many other countries are either unwilling or unable to provide, meaning this program is not feasible outside of China. Because of such limitations, scientists have tried to replicate the state of space on Earth in order to promote the same purposeful space-born mutations on Earth. One such replication is a magnetic field-free space (MF), which creates an area with a weaker magnetic field than that of the earth. The MF treatment produced mutagenic results and has been used to cultivate new mutant varieties of rice and alfalfa. Other replications of room conditions include irradiating seeds with a heavy 7-Li ion beam or mixed high-energy particles. These space-bred strains are already being introduced to the public. In 2011, during the National Lotus Flower Exhibition in China, a mutant lotus named "Space Sun" was displayed at the flower show.

Ion beam technology

Ion beams mutate DNA by removing multiple bases from the genome. Compared to traditional radiation sources like gamma rays and X-rays, ion beams have been shown to cause more severe DNA breaks that are more difficult to weave back together, resulting in the change in DNA being more drastic than changes caused by traditional radiation. Ion beams alter the DNA in ways that make it very different from its original makeup, more than when traditional radiation techniques are used. Most of the experiments with ion beam technology were carried out in Japan. Notable entities using this technology include TIARA from the Japan Atomic Energy Agency, the RIKEN Accelerator Research Facility, and various other Japanese institutions. During the ion beam radiation process, germs are sandwiched between two Kapton films and irradiated for approximately two minutes. The mutation frequencies are significantly higher for ion beam radiation compared to electron beams, and the mutation spectrum is broader for ion beam radiation compared to gamma radiation. The broader spectrum of mutations was demonstrated by the widely varied amount of flower phenotypes produced by ion beams. Flowers mutated by the ion beams showed a variety of colors, patterns, and shapes. New types of plants were cultivated using ion radiation. These plants had the properties of being resistant to ultraviolet light B, disease resistant and chlorophyll deficient. Ion beam technology was used in the discovery of new genes that are responsible for creating more robust plants. However, their most common use is in commercial use to create new flower phenotypes such as striped chrysanthemums.

Ripe pollen treated with gamma radiation

Gamma radiation is used on mature rice pollen to create parent plants that will be used for crossbreeding. The mutated traits in the parent plants can be inherited from their progeny plants. Because rice pollen has a very short lifespan, researchers had to shine gamma rays on cultivated ears of rice plants. Experiments have shown that the irradiated pollen has a greater variety of mutations than the irradiated dry seeds. Pollen treated with 46 Gy gamma radiation showed an overall increase in grain size and other useful variations. Typically, the length of each grain was longer after the irradiated parent rice plants were crossed. The rice progeny also showed a less chalky face, which improved the appearance of the parent rice plants. This technique was used to develop two new rice varieties, Jiaohezaozhan and Jiafuzhan, in China. In addition to facilitating the production of these two rice varieties, irradiation of ripe rice pollen has produced approximately two hundred mutant rice lines. Each of these lines produces higher quality and larger size rice grains. The mutations produced by this technique vary with each generation, which means that further breeding of these mutated plants could produce new mutations. Traditionally, gamma radiation is only used on adult plants and not on pollen. By irradiating mature pollen, mutant plants can grow without being in direct contact with gamma radiation. This discovery is in contrast to what was previously believed about gamma radiation: that it can only cause mutations in plants and not pollen.

Notable varieties of mutagen

Argentina

  • Colorado Irradiado Peanut (X-ray generated mutant; high fat content and yield, 80% of peanuts grown in Argentina in the 1980s were Colorado Irradiado)
  • Puita INTA-CL rice - mutant (herbicide resistance and good yield, also grown in Bolivia, Brazil, Costa Rica and Paraguay)

Australia

  • Amaroo mutant rice variety (60-70% of rice grown in Australia was Amaroo in 2001)

Bangladesh

  • Binasail, Iratom-24, and Binadhan-6 rice mutants
  • Binamoog-5 mutant mung bean variety

Cuba

  • Maybel tomato mutant (excellent drought resistance)
  • GINES rice mutant (made using proton radiation; grows well in salty conditions)

People's Republic of China

  • Henong series soy mutants
  • Jiahezazhan and Jiafuzhan rice (mutations obtained by pollen irradiation; high yield and quality, very adaptable, resistant to plant funnels and explosion)
  • Lumian number 1 cotton
  • Purple Orchard 3 sweet potatoes
  • Tiefeng 18 soybean
  • Yangdao number 6 rice
  • Yangmai 156 wheat
  • Rice mutant Zhefu 802 (irradiated with gamma rays; resistant to rice, good yield even under poor conditions, the most widely planted rice variety between 1986 and 1994)
  • 26Zhaizao Indica Rice Mutant (created with gamma rays)

Czech Republic

  • Diamond barley (high yield, mutant low height created with X-rays)

Egypt

  • High performance rice mutants from Gizeh 176 and Sakha 101

Finland

  • Balder J barley mutant (better drought resistance, yield and germination)
  • Puhti and Ryhti stiff straw oat mutants

France

  • High oil sunflowers (which cover more than 50% of the sunflower area)

Germany

Ghana

  • Tek Bankye mutated cassava (good crushability and increased dry matter content)

India

  • Co-4, Pant Mung-2, and TAP mung bean mutants
  • MA-9 cotton - the world's first mutant cotton released in 1948 (X-rays; drought tolerance, high yield)
  • PNR-381 rice
  • Chickpea mutants Pusa 408 (Ajay), Pusa 413 (Atul), Pusa 417 (Girnar) and Pusa 547 (resistant to Ascochyta disease and wilting diseases and with high yields)
  • Sharbati Sonora wheat
  • Tau-1, MUM 2, BM 4, LGG 407, LGG 450, Co4, Dhauli (TT9E) and Pant Moong-1 Blackgram (YMC, resistance (Yellow Mosaic Virus))
  • Mutant peanuts TG24 and TG37

Italy

  • Durum wheat (especially Creso Mutant, generated with thermal neutrons)

Japan

  • Osa Gold Pear (disease resistance)
  • Most rice varieties grown in Japan have the sd1 mutant allele from the Reimei rice variety

Myanmar

  • Shwewartun mutant rice (made by irradiating IR5 rice for better yield, better grain quality and earlier ripeness)

Pakistan

  • Basmati 370 rice mutant with short height
  • NIAB-78- cotton mutant (high-yielding, heat-resistant, early ripening)
  • CM-72 chickpea mutant (produced with 150 Gy gamma rays; high yield, disease resistant)
  • NM-28 mutant mung bean (short height, uniform and early ripening, high seed yield)
  • Lens mutant NIAB Masoor 2006 (produced with 200Gy radiation; early maturing, high yield, disease resistant)

Peru

  • UNA La Molina 95 barley mutant (developed in 1995 for a growth above 3,000 m)
  • Centenario Amarinth "Kiwicha" mutant (high quality grain and exported as a certified organic product)
  • Centenario II barley mutant (developed for cultivation in the Andean highlands with high yield, high quality flour and hail tolerance)

Sudan

  • Albeely mutant bananas (better quality, high yield and better stand)

Thailand

  • Aromatic Indica Rice Mutants RD15 and RD6 (made with gamma rays and released in 1977-8; RD 15 ripens early, RD6 has a valuable sticky endosperm) Thailand is the world's largest exporter of aromatic rice

United Kingdom

  • Golden Promise Barley (semi-dwarf salt tolerant mutant created with gamma rays) is used in the manufacture of beer and whiskey

United States

  • Calrose 76 rice (short height rice induced by gamma rays)
  • Luther and Pennrad barley (high-yielding mutant varieties; Pennrad also winter-resistant)
  • Murray Mitcham Peppermint ( Verticillium Wilt tolerance)
  • Sanilac bean (X-rays; high-yielding mutant - the Gratiot and Sea-way bean varieties were also crossed from Sanilac)
  • Stadlerweizen (high-performance mutant with resistance to loose dirt and leaf rust and earlier ripening)
  • Star Ruby and Rio Red varieties of Rio Star Grapefruit (made with thermal neutron techniques)
  • Todd's Mitcham Peppermint ( Verticillium Wilt tolerance)

Vietnam

  • VND 95-20, VND-99-1 and VN121 rice mutants (increased yield, improved quality, resistance to diseases and pests)
  • DT84, DT96, DT99, and DT 2008 soybean mutants (developed gamma rays using three grow crops a year, tolerance to heat and cold, and disease resistance)

In 2014 it was reported that 17 varieties of rice, 10 soybeans, two corn and one chrysanthemum mutant were officially released to Vietnamese farmers. 15% rice and 50% soybeans were made from mutated cultivars.

Release by nation

As of 2011, the percentage of all mutagenic strains released worldwide by country was:

  • (25.2%) People's Republic of China 
  • (15.0%) Japan 
  • (11.5%) India 
  • (6.7%) Russia 
  • (5.5%) Netherlands 
  • (5.3%) Germany 
  • (4.3%) United States 
  • (2.4%) Bulgaria 
  • (1.7%) Vietnam 
  • (1.4%) Bangladesh 

See also

References

External links