CN-121986760-A - Method for stabilizing breeder of subtropical silkworm

CN121986760ACN 121986760 ACN121986760 ACN 121986760ACN-121986760-A

Abstract

The invention relates to the technical field of genetic breeding, and discloses a method for stabilizing breedability of a subtropical silkworm intermediate line, which comprises the steps of establishing an initial group from egg circles with optimal screening property in a production group, obtaining second-generation frame breeding by comprehensively screening of a unified life rate, cocoon quality and offspring hatching rate of silkworm chrysalis through hastening hatching and single moth breeding, repeating the single moth breeding screening twice to obtain third-generation and fourth-generation frame breeding, obtaining fifth-generation frame breeding by adopting a 4/4 moth region mixed breeding method, then repeatedly executing the above breeding and screening processes by taking the fifth-generation frame breeding as a new starting point, and continuously implementing at least two breeding cycles every time 4/4 moth region mixed breeding is executed as a breeding cycle until a new silkworm strain with the sum of the seed production rate and the reeding rate being stably lower than 0.5% is obtained. The invention is used for cultivating a new silkworm strain with stable cultivation property and retaining excellent economic character and robustness, and provides support for the stable development of the silkworm industry.

Inventors

LAN YANNI
WEI BOYOU
HUANG LINGLI
LIU YANWEI
SU HONGMEI
WU JINGYAN
MENG YIYING
AN CHUNMEI
TAO JIYANG
HUANG LING
MAO HONGBIN
PU YUEXIA
HE JI
CHEN DEXIAN
LAN BIZHONG
JIA XUEFENG
RAN YANPING
YE JIANWEI
LAI YANMEI
HUANG YANGYU
HUANG HONGYAN
LUO QUN
LI FENGYE
TAN FUYANG
HUANG WENGONG
BI LIHUI

Assignees

广西壮族自治区蚕业技术推广站(广西壮族自治区蚕种质量检验检疫站、广西壮族自治区蚕业科学研究院)

Dates

Publication Date: 20260508
Application Date: 20260129

Claims (10)

1. A method for stabilizing breedability of a subtropical silkworm intermediate line, comprising: S1, eliminating egg circles with seed production rate greater than 30% or egg reproduction rate greater than 30% from the production subtropical silkworm intermediate line varieties, and selecting 10-15 egg circles with the lowest sum of seed production and egg reproduction rate from the rest egg circles as an initial group, wherein if the number of the rest egg circles is less than 10, all the egg circles are selected; S2, carrying out hatching and single moth breeding on an initial population, calculating the uniform life rate, the average whole cocoon quantity and the average cocoon layer quantity of insect pupas in each moth region after breeding is finished, selecting a secondary moth region, further selecting healthy individuals with the average whole cocoon quantity within the region of +/-0.1 g and the average cocoon layer quantity within the region of +/-0.02 g from the secondary moth region as secondary individuals, and carrying out mating and spawning to prepare second-generation frame seed production; s3, taking the second generation frame seed production obtained in the step S2 as a basic group, repeatedly executing the step S2 twice, and sequentially obtaining the third generation frame seed production and the fourth generation frame seed production; s4, taking the four-generation frame seed production obtained in the step S3 as a basic group, and adopting a 4/4 moth area mixed breeding method to breed, wherein the 4/4 moth area mixed breeding method is that after hastening the hatching, 40 to 60 moth rings are selected, 1/4 egg surfaces are taken from each moth ring, 1/4 egg surfaces of 4 different moth rings are combined into a breeding unit to breed, and after the breeding is finished, excellent individuals are selected from the breeding unit, and the five-generation frame seed production is produced through mating and spawning; S5, taking the five-generation frame seed production obtained in the step S4 as a new basic group, and repeatedly executing the single moth breeding and 4/4 moth region mixed breeding and screening processes in the steps S2, S3 and S4, wherein each time the step S4 is executed, a breeding cycle is completed; The method comprises the steps of selecting a next-generation moth area and an excellent individual, firstly, eliminating the moth area with hatching rate, insect pupa uniform life rate or any one of which is lower than the average level of the current raising group, then, screening out the moth area with the insect pupa uniform life rate higher than the average level of the current raising group and with the whole cocoon quantity within the average value + -0.5 g of the current raising group from the rest moth areas as a candidate moth area, selecting 3-4 moth areas with the lowest sum of seed production rate and reeving rate from the candidate moth areas as the next-generation moth, and selecting healthy individuals with the whole cocoon quantity within the average value + -0.1 g and the cocoon layer quantity within the average value + -0.02 g from the next-generation moth areas as the excellent individual.
2. The method for stabilizing breeder's ability of subtropical silkworm according to claim 1, wherein the subtropical silkworm breeder is a binary breeder containing a diversified blood system.
3. The method for stabilizing breeder's ability of subtropical silkworm according to claim 1, wherein the raising condition is that the uniform illumination of 100 lx-300 lx is maintained except for the sleeping period, the temperature is 26-30 ℃ and the relative humidity is 75% -90%.
4. The method for stabilizing breeder' S ability in subtropical silkworms according to claim 1, wherein the step S3 of repeatedly executing the step S2, sequentially obtaining the third generation frame species and the fourth generation frame species, comprises: The first execution, taking the second generation frame seed production as a basic group, selecting 10-15 moth areas from the basic group for hatching and raising, screening according to the excellent individual selection standard of claim 1, mating and spawning the selected excellent individuals to prepare the third generation frame seed production; The second execution, taking the third generation frame seed as a new basic group, selecting 10-15 moth areas from the new basic group for hatching and raising, screening according to the excellent individual selection standard of claim 1, mating and spawning the selected excellent individuals to prepare the fourth generation frame seed; If the number of the hatched silkworm heads of a selected moth area is less than 100, firstly carrying out mixed rearing on the individual in the moth area, and selecting healthy individuals from offspring of the individual for subculturing until the moth area with the number of the hatched silkworm heads being more than or equal to 100 is obtained, and then transferring the moth area into a single moth rearing and screening process.
5. The method for stabilizing breeder of subtropical silkworm as claimed in claim 1, wherein in step S1, the method for pretreating the breeder of subtropical silkworm breeder for production specifically comprises: The primary selection is carried out in the early stage of the hastening of the hatching, egg circles with egg retaining colors and egg shapes conforming to the inherent characteristics of the variety are selected, and egg circles with the defective egg rate higher than 30% are eliminated; Checking in the middle period of the hastening, screening from the egg circles which are qualified in primary selection according to the egg shape, the egg quantity and the number of bad eggs, wherein the number of excellent egg circles, the number of which is 1-1.5 times of the number of the planned final rearing moth areas, is checked as a candidate group; And (3) final selection is carried out after the turning period, and in the check egg circles, the turning time is more than 48 hours, and the eggs are turned to dead eggs for a plurality of egg circles.
6. The method for stabilizing breeder of subtropical silkworm according to claim 1, wherein in the single moth raising process of step S2, the eggs after finishing the collection are soaked in 60 ℃ clear water for 1 hour in the afternoon of the day of the collection, and then the eggs are taken out and dried, the number of hatched eggs and total number of eggs are counted, and the sum of the spawning rate and the reextraction rate of the eggs and the hatching rate of the eggs are counted and calculated.
7. The method for stabilizing breeder properties of subtropical silkworm as claimed in claim 1, wherein the selection of the secondary moth region and the selection of the fine individual are performed in the pupa stage during the raising in steps S2 and S3, and the selection of the fine individual is performed in the pupa stage during the raising in step S4: And selecting a 3-4 moth region with the lowest sum of seed generation and egg emergence rates from the primary moth region, namely selecting excellent individuals, namely selecting cocoon shapes and pupae which do not accord with the inherent characters of varieties, selecting the excellent individuals with the average value of all cocoons within the range of +/-0.1 g and the average value of cocoon layers within the range of +/-0.02 g of the area as the final secondary individuals by taking the average value of the candidate moth region and the cocoon quality character in the raising period as the standard and taking the secondary moth region in which the individuals are positioned as the calculation standard.
8. The method for stabilizing breeder of subtropical silkworm according to claim 1, wherein the feeding condition of S2 is specifically controlled as follows according to the age of the silkworm: For silkworms of 1-2 ages, the temperature is 29-30 ℃ and the humidity is 85-90%; for the silkworms of 3 ages, the temperature is 28-29 ℃ and the humidity is 80-85%; For the silkworms of 4 ages, the temperature is 27-28 ℃ and the humidity is 80-85%; for silkworms of 5 ages, the temperature is 26-27 ℃ and the humidity is 75-80%.
9. The method for stabilizing breeder properties of subtropical silkworms according to claim 1, characterized in that the operation of hastening the hatching specifically comprises: Maintaining the temperature at 26-27 ℃ and the humidity at 85-90% on the 1 st-4 th day of the hastening of the green, and carrying out natural illumination; Maintaining the temperature at 28-29 ℃ and the humidity at 85-90% on the 5 th-8 th day of the hastening of the green, and illuminating for 18 hours every day; and (3) at the 9 th to 10 th days of the hastening of the hatching, keeping the temperature at 28-29 ℃ and the humidity at 85-90%, and carrying out shading treatment.
10. The method for stabilizing breeder of subtropical silkworm according to claim 1, wherein the method further comprises strain comparison verification after finishing breeding, and specifically comprises: feeding the new subtropical silkworm midline strain and the corresponding midline production line in parallel under the conventional production condition and the long illumination condition for at least three generations of spring, summer and autumn; and if the unified life rate, hatching rate, whole cocoon quantity and cocoon layer rate of the new variety of the third generation of the worm pupa under the two feeding conditions are equal to or better than those of the production line, the sum of the seed production rate and the reeving rate is not higher than 0.5%, and the sum of the seed production rate and the reeving rate is obviously lower than that of the production line, judging that the chemical property of the new variety is stable.

Description

Method for stabilizing breeder of subtropical silkworm Technical Field The invention relates to the technical field of genetic breeding, in particular to a method for stabilizing breeder of subtropical silkworm. Background The sex of silkworms, i.e. the number of generations they naturally occur within a year, is an important genetic trait that determines their breeding patterns and agricultural production schedules. The current family varieties such as "Guangdong and Guangxi Provinces No. two" belong to the binarized varieties containing the diversified blood families. This genetic background makes the intermediate cultivar extremely sensitive to changes in environmental conditions. In actual production, fluctuation of conditions such as temperature, light or feed nutrition is easy to cause change of the chemical property, and especially the influence of the light condition on the chemical property is most obvious. The appearance of two abnormal eggs is directly represented by the appearance of a raw seed (non diapause egg), namely, the silkworm eggs do not enter diapause after being laid and are hatched in about 7-10 days without regard to seasons, and the appearance of a second egg is represented by the appearance of a black seed which should enter diapause and is hatched in a season which should not be hatched by accidentally releasing diapause. These phenomena lead to a significant decrease in the rate of diapause eggs (black species) which are the target products. The frequent occurrence of spawning and spawning seriously reduces the yield and quality of silkworm eggs, breaks up the preset production plan and constitutes a continuous threat to the stable development of the silkworm industry. To cope with this problem, the production is currently mainly dependent on environmental regulation means, such as high Wen Ganguang for hastening the hatching, regulating the temperature and humidity of the raising environment, and ensuring good Sang Baoshi. The measures can reduce the occurrence rate of the current generation individual seed generation and the reeving to a certain extent by optimizing the growth and development conditions of the current generation silkworms. However, this method is limited in that its effect is transient and non-genetic. It cannot fundamentally improve the genetic stability of the cultivar, resulting in a treated cultivar whose next generation still recurs in large numbers when subjected to environmental changes, the problem of seed production and reemergence. Therefore, there is a need for a method of breeding stable silkworm breeder lines which has stable genetic traits and is resistant to environmental interference. Disclosure of Invention It is an object of the present invention to address at least the above-mentioned drawbacks and to provide at least the advantages to be described later. To achieve these objects and other advantages and in accordance with the purpose of the invention, there is now provided a method for stabilizing breedability of a line in subtropical silkworms, comprising: S1, establishing an initial group, namely eliminating egg circles with the seed production rate of more than 30% or the reextraction rate of more than 30% from the intermediate line varieties of the subtropical silkworms for production, selecting 10-15 egg circles with the lowest sum of the seed production rate and the reextraction rate from the residual egg circles as the initial group, and if the number of the residual egg circles is less than 10, selecting all the egg circles. S2, breeding second-generation silkworms, namely, carrying out hatching and single moth rearing on the initial population, calculating the hatching rate, the uniform life rate of pupae, the whole cocoon quantity and the cocoon layer quantity of each moth region after rearing, selecting a secondary moth region, further selecting healthy individuals with the average value of the whole cocoon quantity within the region of +/-0.1 g and the average value of the cocoon layer quantity within the region of +/-0.02 g from the secondary moth region as excellent individuals, and mating and spawning to prepare second-generation frame seed production. And S3, multi-generation single moth breeding reinforcement, namely taking the second generation frame seed production obtained in the step S2 as a basic group, and repeatedly executing the single moth breeding and screening process in the step S2 twice to sequentially obtain the third generation frame seed production and the fourth generation frame seed production. S4, mixed breeding and consolidation, wherein the four-generation frame seed production obtained in the step S3 is used as a basic group, a 4/4 moth area mixed breeding method is adopted for breeding, the 4/4 moth area mixed breeding method comprises the steps of selecting 40 to 60 moth rings after hastening the hatching, taking 1/4 egg surfaces of each moth ring, combining 1/4 egg surfaces of 4 different moth rings