Chapter 33 Section 4 Silkworm Hybrid Breeding

Song Yingxing, a famous scientist in the Ming Dynasty, said in "Tiangong Kaiwu": "There are only two kinds of cocoon colors, yellow and white. Sichuan, Shaanxi, Jin, and Henan have yellow and no white, and Jiahu has white and no yellow. If white males are paired with yellow females, Then its heirs will turn into brown cocoons." He also said: "Nowadays in the Han family, there are those who match early males with late females, and this is different." "Illusion" means change, "illusion produces good seeds." , That is to say, the change has produced excellent silkworm eggs.These two records show that at that time silkworm farmers did hybridization of two groups of silkworms.One is to cross a female silkworm that spins yellow silk with a male silkworm that spins white silk.The second is that the male "early silkworm" is crossed with the female "late silkworm".

my country has a vast territory and different climates and environments. The industrious and intelligent Chinese people of all dynasties have bred many silkworm varieties in the long-term practice of sericulture.As far as evolution is concerned, there are monomorphic silkworms, dimorphic silkworms and polymorphic silkworms.Monomorphic silkworm and dimorphic silkworm were the most commonly bred silkworms in the Jiahu area of ​​Ming Dynasty. "Early males paired with late females" mentioned in "Tiangong Kaiwu" refers to the hybridization of monomorphic male silkworm moths and dimorphic first female silkworm moths. "Tiangong Kaiwu" clearly points out the relationship between the male and female of both hybrids, which is very important.Modern sericulture scientists have proved that the sexuality of the silkworm is the same as that of the parental females when monomorphic silkworms and dimorphic silkworms are hybridized.If the parental female is monomorphic, then the first generation hybrid is also monomorphic, and if the parental female is dimorphic, then the hybrid is dimorphic.

According to the genetic law of silkworm hybridization, it can be seen that the "Jia species" produced by "early males mating late females" mentioned in "Tiangong Kaiwu" is dimorphic.This has direct significance in production, and it can be used in production as summer silkworm eggs. Under normal circumstances, "late silkworms" are used to breed summer silkworms. "Tiangong Kaiwu" said: "There are two kinds of silkworms, early and late. The late ones are planted early every year on five or six sunrises, and the cocoons are also formed first. The cocoons are one-third lighter. If the early silkworms form At the time of the cocoon, that (referring to the first silkworm of the late species) has already produced moths and lay eggs for further breeding.” Although the late-species silkworms of the dimorphic nature can be used to pass seeds to raise summer silkworms, as in "Tiangong Kaiwu "As pointed out, its cocoon weight is 1/3 lighter than that of the early silkworm of the same nature.As we all know, dimorphic late silkworms often show excellent traits such as strong physique, high temperature resistance, and suitable for breeding in high temperature environments in summer.But the cocoon silk of this kind of silkworm is indeed lighter.However, the early silkworms are better than the late silkworms in terms of cocoon quantity and silk quality.However, this kind of silkworm has weak constitution and low high temperature resistance, and because it is monogenic, it cannot propagate seeds in summer under natural conditions.Through the hybridization of these two varieties, the hybrid varieties often combine the excellent traits of both parents.Silkworm farmers in the Jiahu area of ​​the Ming Dynasty saw the advantages of hybrid varieties in long-term practice, so they called them "Jiazhong".

Silkworm farmers in the Jiahu area of ​​the Ming Dynasty created a precedent for artificial hybrid breeding of silkworms. After the publication of the book "Heavenly Creation of Things", it has received attention both at home and abroad.In Japan, it became a book commonly read by Japanese during the Tokugawa period. In the middle of the 19th century, the text about sericulture in "Tiangong Kaiwu" was also translated into French by French sinologists and became popular in Europe.Japan and France, which are more developed in sericulture production, will naturally attach importance to the sericulture technology recorded in "Tiangong Kaiwu".Japanese sericulture experts began to engage in artificial hybridization of silkworms in the second half of the 18th century.Initially, they also crossed monomorphic spring silkworm species and dimorphic spring silkworm species to produce hybrid varieties, which may be influenced by the records in "Tiangong Kaiwu".