CN1122441C - Two-stage continuous backcross method for breeding vavous moth of bombyx mori - Google Patents

Abstract

The present invention relates to a two-stage continuous backcross method for breeding gray-black moth of silkworms, which comprises the steps of hybridization, backcross and autocopulation. In the method, firstly, practical varieties of white moths and grey-black moths in silkworm system are hybridized to obtain white moths F1 after feeding and cocooning; white moths F1 are in backcross with the practical varieties of white moths once, and then are autocopulated to breed silkworm eggs; in this way, the first section of continuous backcross is finished. 1/8 gray-black moths are separated from the silkworm eggs after feeding and cocooning, and are hybridized with practical varieties of white moths; the hybridized generation is in backcross with the practical varieties of white moths, and the following generation is autocopulated for separation. The selected gray-black moth individuals are new varieties of silkworms with recessive gene of gray-black moths, and the varieties which inherit the favorable comprehensive economic characters of the selected practical varieties can be directly used for breeding the hybrid of the first generation of silkworms, wherein the thorough rate of hybridization can be reached by 100%.

Description

Two-stage continuous backcross method for breeding vavous moth of bombyx mori

Technical field

The present invention relates to a kind of selection of cultivated silkworm breed variety, specifically two-stage continuous backcross method for breeding vavous moth of bombyx mori.

Background technology

The seed selection of cultivated silkworm breed variety at present also has means mutation breedings such as the ray of employing, laser usually based on crossbreeding.Crossbreeding can just import the specialized character that kind had that contains this specific gene to a certain specific gene practicability of silkworm, and not only integral economic trait reaches the practicability level, and can further improve its economic worth.If this specialized character is subjected to dominant gene (being that specific gene is a dominant gene) control, then crossbreeding can adopt the continuous backcross method to be achieved, and generally backcrosses by 3～4 times and just can shift (importing) to this specific gene in commercial variety.If this specialized character is controlled by recessive gene, then the continuous backcross method very easily makes recessive gene lose, because recessive gene is subjected to the inhibition of dominant gene, this specialized character can not show after the hybridization, thereby does not distinguish whether contain recessive gene in the backcross progeny individuality.According to mendelian inheritance,, select the individuality that contains genes of interest and hybridize again, separate again if adopt hybridization, selfing to separate ... also can import recessive gene, but this method complex operation, progress is slow, and weak effect is difficult to practicality.

The grey black (specialized character) that the greyish black moth of silkworm is presented is exactly to be subjected to recessive greyish black moth Gene Handling.If this gene is imported in the silkworm commercial variety, then the thorough rate of the hybridization of f_1 hybrid eggs of silkworm can bring up to 100%.

Summary of the invention

Breeding of the seed selection of the favourable what silkworm of the importing of silkworm recessive gene breeding and silkworm breeding, if can solve a difficult problem that imports, its meaning will be very great.The application imports the breeding method that recessive gene provides a kind of practicability during for silkworm breeding, and concrete technical scheme is two sections continuous backcrosses.First section continuous backcross comprises hybridization, backcrosses and selfing, hybridization be exactly with in be that the white moth of commercial variety does parent's (calling the white moth of parent in the following text) and the individual hybridization of greyish black moth, complete white moth of gained F1 and the white moth of parent are backcrossed once, and gained first backcross generation moth selfing more once makes the selfing silkworm egg; Second section continuous backcross comprises hybridization, backcrosses and selfing, and hybridization is to separate the 1/8 greyish black moth that obtains with the white moth hybridization of parent with above-mentioned selfing silkworm egg, again continuous backcross once, selfing separates, and selects greyish black moth individuality.This greyish black moth is exactly the new silkworm variety with recessive greyish black moth gene, directly breeding with the what silkworm.

Recessive greyish black moth gene imports convenient, fast with two sections continuous backcross methods, this method of breeding has been accelerated the breeding progress, has improved breeding effect, effectively prevents losing of recessive greyish black moth gene.The new cultivated silkworm breed variety of breeding with recessive greyish black moth gene, its integral economic trait is similar to commercial variety, with the first generation cross-fertilize seed that the Japanese white moth kind of routine combines, can bring up to 100% to the thorough rate of the hybridization of f_1 hybrid eggs of silkworm.

Embodiment

Select the good Chinese system spring of integral economic trait with or the white moth kind of Xia Qiuyong do the parent, with the individual hybridization of the greyish black moth that contains recessive greyish black moth gene, F1 is raised for silkworm in the hybridization back, goes out to be white moth (F1 generation moth) in vain entirely behind the moth.Backcross once with white moth of F1 and the white moth of parent, raise the first backcross generation silkworm, wait to cocoon, go out selfing behind the moth, this is first section continuous backcross.The silkworm egg of making after the selfing, after raising is cocoond, isolate 1/8 greyish black moth, wherein male and female half and half, hybridizes with the white moth of parent and raising filial generation silkworm with isolated greyish black moth again, after waiting to cocoon, going out moth, backcross once with the filial generation moth and the white moth of parent that contain recessive greyish black moth gene (phenotype is white moth), raise again, cocoon, separate after going out the moth selfing, select greyish black moth and reserve seed for planting, this is second section continuous backcross.The greyish black moth individuality of selecting behind two sections continuous backcrosses is the new silkworm variety of breeding that contains recessive greyish black moth gene, has inherited the comprehensive good economic characters of selected commercial variety simultaneously again, directly breeding with the what f_1 hybrid eggs of silkworm.

Claims (1)

1, a kind of two-stage continuous backcross method for breeding vavous moth of bombyx mori comprises hybridization, backcrosses and selfing, and its feature is at what:

(1), first section continuous backcross: at first selecting in the silkworm is the hybridization of the white moth of commercial variety and greyish black moth, the white moth continuous backcross of white moth of gained F1 and commercial variety once, the moth of the gained of backcrossing selfing more once makes silkworm egg;

(2), second section continuous backcross: silkworm egg that above-mentioned selfing makes is raised, is cocoond, and isolates the white moth hybrid generation of 1/8 greyish black moth and commercial variety, again continuous backcross once, greyish black moth individuality is selected in the selfing separation.