Creation of inbred systems with a choice of plus and minus on the viability of silkworms with the best combination value

Scientific research results in pandemic conditions (COVID-19)

22

In Table 2, 30 days before migration, worker bees in the hive gained 6.9

mg or 4.8% of their weight compared to controls. Similarly, 20 days before
the same bees weight, in experimental groups 15.5 mg or 13.5% more than
in the control group.

Conclusion: Before the bee family migrates and separates, it can be

learned based on the physiological changes that take place in the div of
worker bees 20 days before they do so. In migratory families, the size of the
worker bees increases, and the amount of fat in his div increases slightly.
All this is due to the migration of bees that migrate to a new place; they build
a new place, raise a new generation, collect food and process them. In order
to spend the winter well, it fills the hive with young bees and replenishes it
with a large amount of food reserves for a successful winter.

In migratory bee families, worker bees can be identified by physiological

changes in their bodies 30-20 days before the migration.

References:
1.

Мажукин В.С. Борьба с роением. ж. Пчеловодство, 2011, №4, стр.

34-35.

2.

Морьева Л.Я., Козуб М.А. Изменения содержания воды и жира в

теле пчелы в период зимовки. Ж.Пчеловодство, 2011, №1, стр. 16-17.

3.

Таранов Г.Ф. Биология пчелиной семьи. Россельхозиздат

Москва, 1986.

4.

Рыбальченко А.Н. Загадка пчелиного роя. Минск, «Урожай»,

1982.

Daniyarov Umirzak Tukhtamuradovich, Tashkent State Agrarian

University, Professor of “Sericulture and mulberry growing” department.

Suvonova Anzura Dusqoraevna, Tashkent State Agrarian University,

assistant of “Sericulture and mulberry growing” department.

Soxibova Nigora Sadritdtnovna, Tashkent State Agrarian University,

Department of “Sericulture and mulberry growing” 2nd year PhD student.
CREATION OF INBRED SYSTEMS WITH A CHOICE OF PLUS AND MINUS ON

THE VIABILITY OF SILKWORMS WITH THE BEST COMBINATION VALUE

Daniyarov U., Suvonova A. , Soxibova N.

Abstract: There is no difference in performance in systems with plus and

minus selection. In the F-1 and F-3 systems where viability plus selection
was performed, cocoon weight values were 1.84 g and 1.85 g, and shell
weights were 432 mg and 422 mg, respectively. In practice, the minus
selection does not differ from those of the conducted F-2 and F-4 systems -

Scientific research results in pandemic conditions (COVID-19)

23

1.72 g and 1.85 g, respectively; 394 mg and 420 mg. Clearly, the choice of
viability leads to the accumulation of recessive hemispheric and subletal
genes in the homozygous state in the system. As a result, some organisms
die at different stages of development. But some of them survive. Probably
on the one hand, because harmful genes are less accumulated, and on the
other hand, because there are enough positive genes to compensate for the
effects of harmful genes, i.e., the GCC is formed.

Had this process not taken place, no doubt the system would have

perished as a result of negative selection over several generations. It follows
that GCC does not occur in systems with high viability. The predominance of
positive genes over negative genes is achieved without them. In addition, the
process of mutation is accelerated under the influence of negative selection.
This increases gene diversity.

Thus, not only the reserve but also the newly emerging genes remain

the source for the blocks of both categories.

Keywords: Inbred, system, top cross, bottom cross, in cross, heterosis,

hybrid, mulberry silkworm, cocoon, cocoon shell, silkworm.

According to many scientists [V.A. Strunnikov, S.V. Nasriddinova, V.N.

Shushikova N 1979,1987], the use of close kinship in the selection and
breeding of mulberry silkworms can increase the homogeneity of cocoons,
increase of silk production and silk raw materials, it also leads to an increase
in the output, an improvement in the cocooning. Therefore, in the selection
and breeding work with mulberry silkworms, research related to the use of
crossbreeding to strengthen the economic-beneficial traits and increase the
effectiveness of heterosis in crossbred hybrids obtained from interbreeding
hybridization of inbred systems is important.

It is well known that heterosis is particularly pronounced when inbred

systems or strains are mixed with inbred systems. We had 4 inbred
generations of silkworms at our disposal, i.e. strong Inbred Line 48, Line 51
systems. Therefore, it was very interesting to determine how hybrids
between inbred systems and Chinese 108 and Japanese 66 breeds manifest
themselves in terms of technological characteristics of cocoon fiber.

The most effective of the interbreeding systems applied to mulberry

silkworms is the mating of blood-siblings, which provides close
homozygosity in the offspring, in our case, on the viability of silkworms.

Selection-inbreeding creates a high degree of phenotypic and genotypic

homogeneity in the offspring across all genetic traits of the organism. Inbred
reproduction, which is carried out by selecting the best creatures and
disposing of the worst, leads to the creation of systems that are resistant,
viable and productive, free from all negative genetic factors.

Scientific research results in pandemic conditions (COVID-19)

24

In other words, the sum of the genotypes of the ancestors of an isolated

breed forms an immutable hereditary fund, and the genotype of the
generations does not go beyond it.

The combination of viability in the mulberry silkworm genotype with

the high-tech properties of cocoon fiber is a noble goal of all silkworm
practitioners.

[Strunnikova L.V., Strunnikov V.A., Sharova I.G., Yakubov A.B., Pashkina

T.A., Larkina E.A., Tadjiev E.X., Ikramov Z.I. 1999.] According to research, one
of the causes of heterosis is the emergence of a positive genes compensatory
complex (GCC) that is formed slowly during inbred reproduction and resists
inbred depression. In inbred systems, the choice for both high viability and
low viability is the mechanism that triggers the formation of GCC.

There is no official data on the reaction of large cocoon breeds to inbred

breeding, so the study of the possibility of using inbreeding in the breeding
of high-yielding breeds created by synthetic methods will undoubtedly be of
interest, as it is planned to introduce such breeds in Uzbekistan.

Large cocoon selection systems Line 48 and Line 51 were used as

experimental material. Through the Sister to Brother hybridization, each
selection system was previously fitted with two inbred systems: F-1 and F-
2 from Line 48, and F-3 and F-4 from Line 51 systems, the selection was
made on the increased viability of silkworms, and on the F-2 and F-4 systems
- on the reduced viability. In this study, five inbred generations (J5, J6, J7, J8,
J9) were studied and the response of the strains to inbreeds in systems with
targeted selection was determined. The control was provided by silkworms
obtained by outbred crossbreeding of the same species. The results of the
study are presented in Table 1.

Table 1 clearly shows the inbred depression of the F-1, F-2, F-3, and F-4

systems in terms of the number of normal eggs in the stock, the weight of
the stock, and the weight of a single egg. For example, Line 51 has 711 eggs,
while the F-1 and F-2 inbred systems derived from it have 637 and 646 eggs,
respectively. The average weight of one egg in line 48 is 0.587 mg. In F-3 and
F-4 inbred systems derived from it - egg weight was 0.587 and 0.549 mg.
Inbred breeding has led to a certain stabilization of the reproductive traits
of the breed. The coefficient of variation was found to decrease at the end of
inbredization of all parameters in all inbred systems. In the F-1 system, the
Sv in normal seeds in terms of quality was 18.6% in 2007 and -14.8% in
2011. A similar situation was observed in other systems. The confidence
level (Pd = 0.999) for egg resuscitation was calculated.

However, there is almost no difference in reproductive performance

between inbred systems with high and low viability of silkworms. This can
be explained by the fact that there is little or no correlation between the
viability of silkworms in Line 48 and Line 51 and the amount of eggs in the

Scientific research results in pandemic conditions (COVID-19)

25

nest. In that case, survival selection cannot lead to a significant change in
reproductive traits, and we see this in this experiment.

Scientific research results in pandemic conditions (COVID-19)

26

Table 1

Reproductive and hatching indicators of inbred systems (2007-2011

years)

Table 2

Biological indicators of selection inbred systems (2007-2015 years)

*Pd=0,999

In this breed, the correlation between the viability of silkworms and the

number of eggs in the nest was very low and was 0.041. The correlation
between survival and weight of a single egg - 0.126 is also the result of
research [Nasirillaev U.N. 1985.]. Inbred depression significantly bypassed
egg hatching (Table 1).

From the researches of the Turkmen scientist [Mamedov A. 1985.] it is

known that a significant detrimental negative effect of inbreeding on egg
hatching was not observed in not only one-time but also three-, four-time
crossbreeding of close relatives.

In our experience, the hatching of inbred systems is slightly different

than that of controls. For example, the hatching of the F-1 and F-2 systems

Systems

Years

Average number of
normal eggs, pieces

The average weight
of the stock, mg

The average weight of
an egg, mg

Physiologically
unfit %

Hatching of eggs,
%

X

±S

x

Сv,%

X

±S

x

Сv,%

X

±S

x

Сv,%

X

±S

x

Сv,%

X

±S

x

Сv,
%

F-1

J

5

2007

497±19,6

18,6

287±10,1

18,6

0,578±0,001

9,6

3,7±0,06

11,4

96,9±4,0*

3,0

J

9

2011

637±17,1

14,8

371±8,1

13,7

0,581±0,002

7,8

5,2±0,4

13,4

95,3±3,5*

3,4

F-2

J

5

2007

527±17,8

21,1

293±8,4

20,4

0,556±0,001

8,3

2,2±0,5

9,3

94,2±4,1

4,8

J

9

2011

646±14,8.

12,3

368±8,3

10,9

0,570±0,005

4,0

3,2±0,2

8,6

97,4±2,0

3,5

System 51
(comparative)

2011

711±8,7

7,8

392±5,9

10,0

0,580±0,003

6,2

2,1±0,1

6,0

96,1±3,0

3,0

F-3

J

5

2007

438±22,4

24,6

258±10,6

23,0

0,589±0,006

6,0

5,6±1,5

9,2

93,3±5,2

4,1

J

9

2011

619±17,1

13,9

361±9,6

15,6

0,587±0,007

6,0

3,2±1,0

7,4

91,9±5,0

4,2

F-4

J

5

2007

458±27,1

19,0

260±10,1

14,7

0,568±0,007

6,3

4,0±0,1

5,5

87,8±5,1

4,0

J

9

2011

620±17,1

11,6

340±8,7

7,5

0,549±0,005

4,2

4,0±0,5

6,8

94,0±4,9

3,5

System 48
(comparative)

2011

663±6,7

6,2

415±5,3

9,6

0,587±0,005

8,4

5,3±0,1

5,6

96,7±3,0

30,

Systems

Inbreeding
generations

Years Viability of

silkworms, %

The weight of a
shell, mg

The weight of a
cocoon, g

Silkiness,%

Х±Sх

Сv

Х±Sх

Сv

Х±Sх

Сv Х±Sх

Sv

F-1

J

5

2007 66,8±2,8

18,3 384±8,5

9,6

1,05±0,03 6,7 23,4±0,2

3,2

J

9

2011 77,4*±5,8 18,3 432±16,6 9,4

1,84±0,06 7,5 23,6*±0,2

1,7

F-2

J

5

2007 60,9±6,9

43,6 395±8,9

8,7

1,73±0,03 6,4 22,9±0,2

3,4

J

9

2011 77,7±6,1

19,2 394±19,8 12,3 1,72±0,08 7,8 23,2±0,3

3,0

Line-
51(comparative)

81,8±1,9

8,6

515±9,8

7,5

2,05±0,03 5,1 25,1±0,2

3,8

F-3

J

5

2007 54,0±3,9

29,5 377±8,4

9,2

1,72±0,03 7,5 22,1±0,3

1,1

J

9

2011 84,9±3,9

11,2 422±13,3 13,5 1,85±0,06 7,8 22,8±0,7

6,9

F-4

J

5

2007 53,1±3,5

28,2 405±12,4 12,2 1,72±0,04 9,1 23,8±0,03

4,8

J

9

2011 78,3±5,7

17,7 430±4,9

2,8

1,85±0,02 2,2 23,2±0,2

1,6

Line-
48(comparative)

84,7±1,6

8,2

534±10,0 6,9

2,11±0,03 4,8 25,2±0,3

4,0

Scientific research results in pandemic conditions (COVID-19)

27

is 95.3% and 97.4%, while in the L-51 control it is 95.1%. This was done in
an experiment with the S-5 breed, where the highest coefficients of
phenotypic correlation were found between silkworm viability and egg
hatching, cocoon weight, and egg weight in the nest [Nasirillaev U.N. 1985.]
is consistent with the results obtained. Seed viability in systems with such
viability plus selection is as follows: in F-1 - 95.3%, in F-3 - 91.9%, and in
minus-selected systems - F-2 - 97.45 and in F-4 - 94.0%.

An interesting picture is observed on the viability of silkworms, and this

can be seen in Table 4.1.2.

In experiments [Shurshikova NV, Nasriddinova SV 1981.], a decrease in

viability in the first inbred generations of SANIISh-21 and SANIISh-30 was
observed, and in all subsequent generations from the fourth generation on
bred material viability was high and not less than control, but it was even
greater than that of the control.

The viability of the systems studied in our experience is appropriate

with the control.

However, no stabilization of viability has been observed across inbred

generations. This is also evidenced by the high coefficients of variability in
all inbred systems. For example, Sv = 18.3% in F-1, Sv = 19.2% in F-2, and
8.2% in control. This is explained by the fact that the viability of mulberry
silkworms is closely related to external environmental conditions.

[Strunnikov V.A. 1994.] noted that mulberry silkworm breeds are

saturated with a large number of harmful recessive genes, some of which,
especially in kinship reproduction, become homozygous, thus creating a
constant source of variability in quantitative traits. In our experience, this is
indicated by indicators such as shell weight, cocoon weight, and silkiness.

There is no difference in performance in systems with plus and minus

selection. In the F-1 and F-3 systems, which were selected for viability plus,
the cocoon weight values were 1.84 g and 1.85 g, and the shell weights were
432 mg and 422 mg, respectively. In practice, the minus selection does not
differ from those of the conducted F-2 and F-4 systems - 1.72 g and 1.85 g,
respectively; 394 mg and 420 mg. Clearly, the choice of viability leads to the
accumulation of recessive hemispheric and subletal genes in the
homozygous state in the system. As a result, some organisms die at different
stages of development. But some of them survive. Probably on the one hand,
because harmful genes are less accumulated, and on the other hand, because
there are enough positive genes to compensate for the effects of harmful
genes, i.e., CCG is formed.

Had this process not taken place, no doubt the system would have

perished as a result of negative selection over several generations. It follows
that CCG does not occur in systems with high viability. The predominance of
positive genes over negative genes is achieved without them. In addition, the

Scientific research results in pandemic conditions (COVID-19)

28

process of mutation is accelerated under the influence of negative selection.
This increases gene diversity.

Thus, not only the reserve but also the newly emerging genes remain

the source for the blocks of both categories.

Reference:
1. Насриддинова С. Жизнеспособность шелкопряда и масса кокона

при инбредном разведении меченной по полу и немеченой породы.
//В сб. «Достижения генетики и селекции тутового шелкопряда и
шелковицы. -Ташкент. В. 6, 1978. –С.103-119.

2. Насриддинова С., Шуршикова Н.В. Изменение гетерозиса под

влиянием отбора при инбредном разведении тутового шелкопряда.
//В сб. «Научные основы развития шелководства». //В.13, -Ташкент,
1979. –С.49-54.

3.

Насриддинова

С.В.,

Струнников

В.А.

Становление

комбинационной способности у инбредных линий тутового
шелкопряда. -1991, -Т.318. -№3.-С.736-740.

4. Струнников В.А. Генетические методы селекции и регуляции

пола тутового шелкопряда. //М., Агропромиздат, 1987 г.-С.12-154.

5. Струнников В.А. Природа гетерозиса и новые методы его

повышения, //Москва, «Наука», 1994 г.-С.3-103.

6. Насириллаев У.Н. Генетические основы отбора тутового

шелкопряда. //Изд-во «Фан», - Ташкент, 1985.-С.3-50.

7.Daniyarov U.T. Abstract of Doctorate dissertation 2019.

Nargiza Dusmukhamedova Independent researcher of the Academy of

Public Administration under the President of the Republic of Uzbekistan

SOME ASPECTS OF ENSURING THE RIGHTS OF CHILDREN TO EDUCATION

IN CASE OF A PANDEMIC

N. Dusmukhamedova

Abstract: The article discusses some topical issues of ensuring the right

of children to education in a pandemic. The transition to a distance and
online system of continuing general secondary, secondary special and
higher education in Uzbekistan, the positive and problematic aspects of this
system, the results of studying the experience of international organizations
and foreign countries in this field are discussed.

Key words: the right to education, the impact of the pandemic on the

education system, online education, distance learning, UNICEF initiatives, a