Chapter 32 Section 3 Utilization of Biological Genetic Variation

Since the Qin and Han Dynasties, people have consciously used the ubiquitous heritable variation of organisms to carry out directional artificial selection and cultivation, resulting in many excellent varieties. In the "Book of Si Sheng" in the Han Dynasty, specific requirements were put forward for the selection of various crops: wheat should be selected with strong ears, and millet should be selected with solid colors and good ears. "Qi Min Yao Shu" not only proposes to choose solid color and good ears, but also "don't harvest" (harvest separately), plant them in the seed field, and store them separately when harvesting.What needs to be mentioned here is that in ancient my country, in selective breeding, the single plant selection method was also applied.According to the "Kangxi Jixia Gewubian", at that time, there was a tree hole in Ula (now in Jilin County, Jilin Province) that "suddenly grew a family of white millet". I can’t stop, so I’m so full of mu hectares, the taste is sweet, and the nature is soft.” After Emperor Kangxi obtained this fine variety of white millet, he also asked people to conduct experiments in the villa, and the results proved that the stems, leaves, and ears of this white millet were better than those of other varieties. It is twice as big and matures quickly. It really is a good breed.The success of this single plant breeding has greatly inspired Kangxi.From this, he deduced that the various excellent crop varieties in ancient times were by no means original, but were gradually formed by people through the selection and breeding of variation.He said: "If you think about the various Jiagu in ancient times or those who were born later, that's probably the case." Later, he applied this single-plant selection method and successfully bred a high-quality early-maturing and high-yielding rice, named Yudao.According to the previous book, what happened is like this: Once, when Kangxi was patrolling the field, he "suddenly saw a rice plant that was taller than all other rice plants". He also found that this rice plant matured earlier than ordinary rice. In the second ten days of the month, ordinary rice "ears of grain" (grain filling), but the seeds of this rice plant have been "firm".In order to find out whether this precocious trait can be inherited?Kangxi collected the seeds of this rice alone, and planted them in the field in the second year.The results proved that the early-maturing trait of this rice plant is hereditary, and it matures first in June, and "it will continue to grow from now on, and it will be thousands of years old."For a long time, it has been the main source of rice used in the palace.Kangxi further deduced that since this kind of rice is suitable for planting in the Northeast region with a short frost-free period, it should also be suitable for two crops a year in the Jiangnan region with a long frost-free period.Therefore, he decided to promote it in a larger area. In 1715 AD, he first promoted planting in Jiangsu and Zhejiang regions. In the first year, he achieved two crops a year in Suzhou region.In the process of promoting "Royal Rice", Kangxi always insisted on conducting comparative experiments between "Royal Rice" and ordinary rice.As a result, in the second year of the promotion of "Royal Rice" in Jiangsu and Zhejiang, the combined yield of the two seasons has reached five stones and two buckets per mu, which is one stone and three buckets more per mu than the control field.The effect of increasing production is very obvious, and it will soon be extended to Anhui, Jiangxi and other places in the future.

In "The Four Arts of the People of Qi" written by Bao Shichen in the Qing Dynasty, there is a volume of "Nongzheng", which describes farming affairs.He proposed to choose a single ear in the fertile land, and divide the harvest and save.He called this single ear selective breeding "one ear transmission".This breeding method of one ear transmission is an out-and-out single plant selection method. China is the hometown of goldfish.The ancestor of goldfish is "golden crucian carp", which has attracted people's attention as early as the Northern Song Dynasty.In the Southern Song Dynasty, goldfish gradually became the favorite ornamental animals of the Chinese people.At that time, many dignitaries, nobles and monks rushed to search for and build ponds to raise crucian carp as entertainment.Zhao Gou, Emperor Gaozong of the Southern Song Dynasty, once built fish ponds in his palace in Hangzhou to raise crucian carp.According to the "Changhua County Chronicles", in 1186 AD, Zhao Gou also sent people to the mountains of Changhua County, 200 miles away from Hangzhou, to catch gold and silver fish to enrich his goldfish pond.Yue Ke, the grandson of Yue Fei, a famous patriotic general in the Southern Song Dynasty, also described the raising of golden crucian carp at that time in the "History of Tingting Hall".He said: "There are people who raise fish in China today. The fish that can be changed are golden, crucian carp is the first, and carp is second. The nobles often dig stones for ponds, and put them in the eaves [you have] for play. Ask about their skills. , Secretly refused to say. Or it is said that the small red worms in the Weiqu in the market [Huanhuan] feed the fish for a hundred days. The first white is like silver, then gradually yellow, and after a long time it will be golden. I have no time to test whether it is true or not. And In addition, there are black seals of snow quality, whose 〔〔〕〕〔li〕 is like lacquer, and it is called a hawksbill fish, and its literary talent is particularly impressive." The golden crucian carp entered the family pond from the release pond, and it has completely embarked on the road of domestication.Its growth, development and reproduction are greatly influenced by humans.From the records in "History of the Wall", it can be seen that a set of methods for raising goldfish had already appeared at that time, and it was already known that red worms (zooplankton of water fleas) were the favorite food for goldfish.In 1241 A.D., Dai Zhi wrote in "Shu Pu": "Nandu stationed [bibi] princes and nobles, the gardens are built in competition, and the method of raising them is well known. There are two kinds of gold and silver crucian carp, and there are also golden loach. Gold (饮字去食化鱼) [can ginseng] is rare. The fish roe are mostly swallowed by themselves, and they are often placed on the pond with scorpion grass, and the seeds are released, and the water is exposed to dryness, and the water is changed again to revive the fish.” It can be seen that goldfish breeding was carried out at that time. , has also been carried out under manual control.

Due to the increasing number of people watching goldfish, in the second half of the 13th century, there was already an industry specializing in raising and selling goldfish - Yuerhuo.Wu Zimu's "Meng Liang Lu" said: "Goldfish are silver-white and tortoise shell-colored... Today, there are many livestock outside the Qiantang Gate. They are sold in the city, and they are known as fish. The mansions of the rich and noble mansions are livestock." The above situation shows that in the Southern Song Dynasty, goldfish not only gradually became the favorite ornamental animals of the Chinese people, but also due to the careful cultivation of the masses, the white and piebald fish had been selected from the color variation of its ancestor "golden crucian carp". Two new varieties.

From the 13th century to the 16th century, goldfish were gradually changed from being raised in ponds to being raised in pots. The success of raising goldfish in pots enabled goldfish to be further promoted and popularized.Li Shizhen said in his book that goldfish "have been stored since the Song Dynasty, but now they are raised and played everywhere." It can be seen that by the end of the 16th century, raising and playing with goldfish has become quite popular in our country.The popularity of raising goldfish has created more favorable conditions for cultivating new varieties of goldfish.Raising goldfish in pots also greatly facilitates people's observation and research on goldfish.Our ancestors have continuously improved the breeding technology of fine goldfish varieties (Figure 21).Zhang Qiande introduced his experience in "Cinnabar Fish Book" (AD 1596) and said: "Most people who do good things raise cinnabar fish (goldfish) as well as domestic materials. The species are expensive and the selection is expensive. Thousands of them must be taken from the summer market every year. The heads are divided into dozens of tanks. If the bad ones are removed every day, one or two of the hundred will be stored in two or three tanks. If you cultivate them carefully, you will have all the natural wonders." This large-scale careful selection began in the middle of the 16th century. In the 100 years to the middle of the 17th century, new varieties such as streaky fins, double tails, double anal fins, long fins, protruding eyes, and short bodies were continuously cultivated.By the 19th century, conscious artificial selection was known. "Goldfish Atlas" (1848 A.D.) said: "When biting, the male fish must choose a good product, which is commensurate with the color and size of the female fish." Breeding effect.In just over 70 years from 1848 to 1925, 10 varieties such as black longan, lion head, goose head, sky-watching eye, blister eye, pompon, gill turning, purple, blue, and ball scale were bred.In recent years, there have been more variant varieties, estimated to be more than 160 kinds.Darwin paid great attention to these facts and systematically described the process and principle of artificial selection of goldfish in China. (Figure 22)

The cultivation of colorful goldfish is China's important contribution to the beautification of people's lives in the world.In 1502 A.D., Chinese goldfish were introduced to Japan, and in 1611 A.D. to Portugal. In 1728 A.D., due to the successful artificial breeding in the Netherlands, they spread throughout Europe. After 1900 A.D., the United States successively introduced goldfish species from Japan and China. People generally like to watch animals. Ancient people used biological variation to breed many flower varieties.In the Song Dynasty, Liu Meng once described 35 chrysanthemum varieties in the book "Ju Pu".Facing so many weird and colorful chrysanthemums, he realized a very profound truth.He believes that no matter whether it is chrysanthemum or peony, in ancient times, there were not as many varieties as there are now. Chrysanthemum and peony, like chrysanthemum, often mutate.As long as people select and preserve its variation every year, new chrysanthemum varieties can be obtained.The reason why there are so many new chrysanthemum varieties now is the continuous selection and variation.He also believes that both peonies and chrysanthemums are still mutating now, and will continue to mutate in the future. As long as "good people" continue to make selections, new varieties will continue to form and appear.This view of variation and the continuous selection of variation as the reason for the development of organisms from a few types to a majority type reflects the ancient Chinese concept of biological change and development, which has a profound impact on future generations.

Xia Zhichen of the Ming Dynasty further realized the relationship between "sudden change" (mutation) and the variety of flowers.He said in "Bo [bo] State Peonies": "The species of peonies are different, and the seeds are also the ones that change suddenly." More than 300 years ago, Xia Zhichen used "sudden changes" to explain the differences in peony species. It is very commendable.The term "sudden change" here is equivalent to the term "mutation" coined by the Dutch botanist De Vries in the early 20th century.Of course, due to the limitations of the times, it was impossible for Chinese scholars at that time to put forward a complete mutation theory like de Vries did later.

In short, ancient my country has rich experience in artificial selection breeding.Darwin once absorbed rich nourishment from the experience of artificial selection in ancient my country and spoke highly of it.In his work "Variation of Animals and Plants under Domestication·Artificial Selection", he wrote: "In the previous century, the 'Jesuits' published a huge work on China, which was mainly based on Compiled by the ancient "Encyclopedia of China". Regarding sheep, it is said that 'improving their breeds lies in carefully selecting those lambs intended for breeding, giving them rich nutrition, and keeping the flock separate'. The same principle is applied to planting plants and fruit trees. The emperor issued a decree to advise people to choose significantly large seeds, and even the emperor himself made the selection... Regarding flower plants, according to Chinese tradition, peonies have been cultivated for 1400 years, and 200 to 300 varieties have been bred." Darwin has studied many works in China, and he is familiar with the great achievements China has made in artificial selection and breeding.He believes that, in fact, ancient Chinese people have discovered the principle of artificial selection.Therefore, he said in "Origin of Species: Variation in Domestication": "If you think that the principle of selection is a modern discovery, it is too far from the truth... In an ancient "Chinese Encyclopedia", there are already A clear statement of the principle of selection."