Breeding began long before the world first heard of Michurin. Many centuries ago, man, albeit unconsciously, selected the largest seeds for sowing and provided artificial selection for plants with the traits he was interested in. What we see today on the shelves of vegetable and fruit stores is not only the result of genetic modification, but also the work of all mankind.
Go to an online organic grocery store and you will find, for example, jam made from juicy red grapefruits. You would think, what’s so amazing, because this is how nature made it? Or is it?
What could be better for a foodie than organic red grapefruit? No pesticides were used to grow it, and it is not genetically modified. In short, this fruit is a dream come true!
The origin of organic products
Red grapefruits, which, along with 3,000 vegetables, fruits, grains and other plant groups, are eaten by millions of people every day, were actually introduced to the planet in this form by mutagenesis. Plants have been exposed to radiation in the laboratory, and we are faced with only the result of years of experimentation.
Over the past 60 years, mutagenesis has resulted in a tremendous amount of food. New varieties of wheat, including the most popular for making the best varieties of Italian pasta; vegetables, fruits, rice, herbs, and cotton have all appeared because of gamma ray irradiation or exposure to toxic substances. Sometimes these methods were used in combination. Of course, such experiments were conducted in order to obtain better products with improved taste, disease resistance and increased stamina of the plants that produce these fruits. Today these products are sold around the world as organic.
Mutations, or physical changes in an organism’s DNA, are the basis of the theory of evolution. Genetic changes can occur due to failure in reproductive processes, exposure to radiation and other factors, and they can cause changes in the appearance or taste of a product. Natural or artificial selection ensures that a new species appears in the plant nomenclature or that changes are maintained for an existing species.
One of the main limitations in creating new plant species is that breeders can only work within the limits of what is available in nature – to develop traits that are already in place. You can’t create new color, taste, or disease resistance that will make a species commercially successful if you can’t get them from genetic material.
In the late 1940s, plant breeders confronted this problem using one of the newest advances of the time, radiation. In an attempt to find peaceful applications of atomic energy, scientists found that irradiation of plants disturbed the structure of DNA and produced mutations. Radiation made it possible to generate mutations at a much faster rate, giving a greater chance of producing a product with new qualities.
According to research data, thousands of new species have emerged precisely because of mutations caused by gamma rays, X-rays or chemical exposures.
Red grapefruit’s colorless past
When grapefruits began to be cultivated in the United States, they were not suitable for agricultural use and were not even considered articles of consumption. An American horticultural magazine in the late 19th century referred to the fruit as “thick-skinned and useless. The aforementioned red grapefruit mutation was the result of several years of laboratory experimentation – it was only through them that the fruit gained commercial value. In 1929, Texas farmers discovered that the flesh of the fruit of one of the trees was not white, but slightly pinkish. It was this tree that gave rise to the ruby-red fruit variety.
Further work with plants obtained from this tree allowed scientists to achieve not only a brighter shade of fruit, but also an almost complete absence of seeds in them. The Star Ruby and Rio Red varieties were introduced in 1971 and 1985, respectively. By now they account for about 75% of the grapefruit crop in Texas.
Mutagenesis or organic origin?
Mutation-based breeding is also of great importance in combating various plant diseases. One of the leading varieties of the Japanese pear, Nijisseiki, might have been lost forever as a species decades ago if not for the work of breeders on its mutations. The species, which accounted for 28% of Japan’s pear crop in 1990, was highly susceptible to scab disease. In 1962, Nijisseiki seedlings were irradiated with gamma rays in the hope that this would make the species more resistant to the disease. In 1981, after almost 20 years of experiments, the goal was achieved: scientists obtained a plant that showed no signs of susceptibility to the disease at all. Thus, in 1991 a new species – Gold Nijisseiki – was introduced to the world, an outstanding achievement in the field of mutagenesis.
Fruit produced by mutagenesis has been sold in supermarkets for decades without any labels or information about its genetic origin. These varieties may also have been labeled as organic because they were grown in accordance with all other requirements for organic production. They are not subjected to any tests, although mutation breeding still requires years of constant work to separate desirable qualities from undesirable ones.
Although mutational selection is recognized as an obsolete technology, it allows researchers to quickly identify the presence of a mutation in individual genes. Many scientists are concerned about the limitations of genetic engineering-based selection, in part because its use will resonate with the ranks of organic product proponents who are willing to accept the incidental results of radioactive or chemical mutagenesis.
Today, mutagenesis is widely used as an alternative because the gene can be destroyed by mutation and no restrictions are imposed on the resulting new species. The time-consuming process of registering transgenic products in the European Union has forced breeders to return to mutational breeding.
Crop genetics research is an object of controversy and misinformation. But, surprisingly, mutation breeding, being undoubtedly the most radical and least understood form of gene manipulation, still meets no opponents and successfully gives us new plant species that have been favored by consumers for half a century.