Study On Characteristics And Breeding Techniques Of Silkworm Stock Seed In Subtropical Zone

Planting mulberry trees and raising silkworms is a great invention of the Chinese nation and has a history of more than 5,000 years.China is still the largest producer of silk in the world,and Guangxi is the largest production base of the subtropical silk industry in China and the world.By 2015 the production of silkworm cocoon and raw silk products accounted for 50.6%and 33%respectively.Silkworm eggs breeding is an important work of sericulture production.The current system of silkworm breeding are three stage breeding which include the original parent silkworm,original silkworm,common silkworm and our stage seed production which include mother seeds of an original silkworm egg,breeder's stock,original seed and normal seed.This paper through long year breeding and research observation on the mother seed,original seed and normal seed of "Liang Guang 2" and "Gui Can 2",which are the main varieties in the subtropical silkworm region represented by Guangxi,carried out 3 method incubation,protecting cocoon by different temperature,monitor providing moths when pupa and female moths in cold condition for seed production,then gets the conclusion as follow.1.Summarized the variety characteristics,breeding technology of breeder's stock and mother seed include "932","7532","Xiang hui","Fu rong","8810","8711" and original seed of sub-tropic varieties "Liang Guang 2" and "Gui Can 2" of Guangxi systematically at the first time.2.The test results of different incubation method explicated that silkworm variety which containing multivoltine pedigrees is more suitable for the two section incubation method.Especially the "932","7532" mother and the original seed using two incubation method can keep the original characteristics of varieties when the high incubation temperature and long illumination conditions.Otherwise,it is easy to produce non hibernating eggs and bad eggs.3.In the result of monitor providing moths when pupa and female moths' in cold condition of regulation of hair moths for cross breed,all the tested silkworm varieties showed more suitable than refrigerated silkworm moth,in particular,the mother moth of the "932" species is more sensitive to low temperature.The regulation of hair moths for cross breed in production should be avoided the female moth in cold storage,otherwise the production of silkworm eggs are often prone to more overlapping eggs,irregular eggs,oviposition reduction and so on.4.The prevention and control of pebrine in the breeding of subtropical silkworm species is especially important,during breeding and seed production of original silkworm,strict control disinfection and disease prevention technology and measures to prevent cross infection of insects in the field,in addition,full immersion disinfection of mulberry and harmless treatment technology play a very obvious effect for prevention of pebrine disease in original silkworm rearing,but it should be used carefully in wet seasons when rainy.