Are all crops that can't be planted genetically modified?

Introduction: Some people often regard the improper storage of seeds as the "sin" of genetically modified seeds. In fact, not all the seeds that can't be kept are genetically modified seeds, but all the seeds that can't be kept are because they take advantage of hybridization. The judgment of transgenic seeds depends on scientific methods such as molecular detection, not simple observation. Hybrid breeding not only greatly improved the grain yield in agricultural production, but also promoted the development of the whole seed industry. Myth: All seeds that can't be planted are genetically modified, and all genetically modified seeds are sterile. Farmers have kept their seeds for thousands of years, and it is exploitation for farmers not to keep them. Truth: Can seeds be preserved as a criterion for judging whether seeds are genetically modified? In fact, whether crops can be preserved depends only on the way of breeding, and has nothing to do with transgenic technology. Using hybrid technology, the seeds with heterosis are not suitable for seed retention. Not all the seeds that can't be kept are genetically modified seeds. From a technical point of view, not all genetically modified crops can not be preserved. Only in some countries, farmers are not allowed to keep seeds because of the legal agreement. Seeds are very important in planting and production. Good seeds mean that the crops planted are resistant to insects, diseases, droughts and waterlogging, and have high yield. The core of breeding industry is how to select seeds with excellent characters. At present, many excellent crop varieties in the world are cultivated through cross breeding. These hybrids have a very remarkable feature: their offspring are not suitable for reproduction, which is often said to be "unable to keep seeds." Some people say that this deprives farmers of their seed sovereignty, while others associate it with transgenic technology. Is this really a conspiracy of the seed company? What does it have to do with transgenic technology? Learn about heterosis first. Heterosis and Utilization of Heterosis: Why Cross Breeding? The most important reason is that hybrid breeding can produce heterosis. Heterosis refers to the phenomenon that offspring obtained by crossing two parents with different genotypes are superior to their parents. The so-called parents, for example, your parents are your parents and you are their descendants. Being superior to parents here does not mean that hybrid offspring are superior to parents in all aspects, nor does it mean that hybrid offspring must have traits that meet human needs. The performance of heterosis of hybrid offspring needs to be analyzed in combination with the specific characteristics of specific organs. Because of the characteristics of hybrid offspring, human beings have widely carried out the practice of heterosis utilization in agricultural production. Different from the general scientific and technological development of "theory first, then application", heterosis has been studied by scientists after a long period of application by human beings. For example, descendants of mules, horses and donkeys have both the strength of horses and the endurance of donkeys. /kloc-it was recorded in ancient books 0/400 years ago, and the history of human utilization of heterosis was obviously earlier than this. In the west, Mendel and Darwin both mentioned the superiority of hybrid offspring in their respective works. Although modern science has been studying heterosis for a long time, the mechanism of this phenomenon has not been fully clarified. The main hypotheses are dominance hypothesis, Super dominance hypothesis, Epistatic Hypothesis and Genome Cutting Theory. Because heterosis is very different in different crops, we have reason to believe that the mechanism of heterosis is different in different species. The most successful case of modern humans applying heterosis to crops is undoubtedly hybrid corn. In addition to heterosis, maize has obvious inbreeding decline, which is just the opposite of heterosis. The closer the parental genotypes are, the weaker and lower the corn yield is. In the early production of hybrid maize, the yield of maize inbred lines (offspring with relatively homozygous genotypes produced by continuous generations of maize per plant) is relatively low, and two-way hybridization-the combination of four inbred lines parents is mainly used to produce the seeds obtained by offspring hybridization. At present, hybrid corn is basically a single cross-the offspring of two inbred lines. At present, the sown area of single-cross maize in China has accounted for more than 90% of the total sown area in China. Other crops, such as wheat, rice, sorghum and cotton. There are also important research and popularization of heterosis utilization. The changing history of maize yield and cultivated varieties in the United States. As can be seen from the figure, when two-hybrid and one-hybrid are used, the corn yield in the United States has been significantly improved. /Kendall R. Lamkey's maize breeding and quantitative genetics research project Why can't hybrid seeds stay? At the beginning of the article, it is mentioned that hybrid offspring cannot be kept. By reviewing the pea experiment of Mendel, a pioneer in genetics, this paper studies in detail why hybrid offspring can't keep seeds. Mendel's pea experiment and character separation /anthro.palomar.edu Pea is a self-pollinating plant, and its parents can be considered as homozygotes, that is to say, the genotypes on the two pairs of chromosomes are the same. In Mendel's experiment, the seeds (i.e. the first generation) have the same traits after one cross, but if the first generation crosses itself (to get the second generation), its offspring will have obvious traits separation. In Mendel's experiment, the offspring of a yellow pea and a green pea are yellow. However, the second generation produced by self-pollination of this first generation of yellow-seed-coated peas has yellow and green seed coats. This phenomenon is called character separation. In agricultural production, just as farmers who plant hybrid corn leave corn seeds and plant them the next year, they will find that the yield is far less than that in the first year, and the ability to resist pests and diseases will also decline, all because of the disappearance of heterosis and the separation of traits. Moreover, through the calculation in genetics, the more selfing generations, the more homozygous individuals with different genotype combinations in offspring.