Be wary of new diseases and bring new diseases
The selection of new and excellent varieties is undoubtedly an important measure for increasing production and income, but there are also several issues that need to be addressed. In the middle of the last century, Oat Crown Rust was endemic in the United States. In order to prevent Oat Crown Rust, in 1942 the Iowa State of the United States began to promote an oat variety called Victoria. It is derived from wild oats, and is resistant to oat stem rust and smut, in addition to its resistance to oat crown rust, and is therefore highly favored by farmers. By 1945 two varieties of the Victoria family had already occupied 97% of the oat seed area in the state. In the second year, people were surprised to find that these varieties began to have a new leaf spot disease at the seedling stage and the epidemic was very fast, causing serious losses to oats for two consecutive years. The pathogens causing this disease have been identified as occasional parasitic fungi on local weeds. It can be said that the pathogen was unknown in the past. If it were not for humans to promote Victoria, it would not be possible to become famous. Therefore, it was named Victoria Bacteria. After gradually replacing the Victoria strains after 1947, the disease was controlled. Of course, there are climatic reasons for the disease epidemic in those two years, but the promotion of so-called disease-resistant varieties is highly sensitive to some minor diseases, which will lead to new diseases. Neither breeders nor farmers need to learn the lessons of playing wolf at the front door and raising tiger at the backyard. On the other hand, we must also consider how to use good breeds. In the 1950s, China began to popularize Bima No.1 from the Guanzhong region. Due to its good adaptability, high yield, high quality, and resistance to strip rust, the planting area expanded rapidly. By 1960, the sown area in North China and Northwest China reached 90 million mu. This year wheat stripe rust was a pandemic, when the wheat production loss was very large. After research found that wheat stripe rust fungus individuals in the same form, but can be divided into many races, they infect different species, like A key opens a lock. When we promote a single species in large numbers, although it is known as “resistance to diseaseâ€, it will always provide unique treatment for individual non-resistance races. Over time, it will raise a new advantage race. After identification, in 1960, more than 70% of the strains in the stripe rust bacterial community belonged to race number 1. They overcame the disease resistance of Bima 1 and they were indirectly raised by people. This experience tells us that the cultivation of single disease-resistant varieties cannot be sustained, and that several strains of varieties must be introduced at the same time. Advocate genetic diversity. Of course, there is another issue that should not be overlooked. That is, when introducing new varieties, do not forget to implement strict quarantine measures, especially from foreign countries. The introduction of U.S. cotton in the 1930s brought cotton fusarium wilt disease, and the introduction of Japanese sweet potatoes spread sweet potato black mite. This is the best example. Safety 3Ply Face Mask, Protective Face Mask, Non Woven Surgical Mask, Anti virus Surgical Mask GUANGZHOU HTD INTERNATIONAL , https://www.maskhtd.com