Haploids are individuals that have only a single set of chromosomes. Because they have only a single set of chromosomes, every detrimental allele will be expressed, since none will be hidden by a dominant allele in the heterozygous condition. As such, it is doubtful that many haploids will survive very long. Haploid medaka , common carp , masu salmon , rainbow trout , Atlantic salmon , chum salmon and plaice have been produced for experimental purposes, but none lived long.

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NOAKHALI SCIENCE AND TECHNOLOGY UNIVERSITY
Department of Fisheries and Marine Science
Course Title : Fish Genetics
Course Code : FIMS 3105 ,Year 3 Term 1
An Assignment On
Production of Haploid and its Significance
SUBMITTED TO SUBMITTED BY
Priyanka Rani Majumdar
Assistant Professor ,
Department of Fisheries & Marine
Science , NSTU
Nazmul Haque Syekat
ROLL :ASH1802050M
YEAR _3 TERM _1
Date of Submission : 14th February 2021

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Index of this Assignment
SL NO NAME OF TOPICS PAGE RANGE
1
Introduction 3-3
2 What is Haploid ?
3-4
3 Production Process of Haploid
5-5
4 Significance of Haploid Production:
5-7
5
Applications of Haploids 7-7
6
Conclusion 8-8
References 8-9

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Production of Haploid and its Significance
Introduction:
Haploids are individuals that have only a single set of chromosomes. Because they have
only a single set of chromosomes, every detrimental allele will be expressed, since none
will be hidden by a dominant allele in the heterozygous condition. As such, it is doubtful
that many haploids will survive very long. Haploid medaka , common carp , masu salmon ,
rainbow trout , Atlantic salmon , chum salmon and plaice have been produced for
experimental purposes, but none lived long.
“Haploids are defined as saprophytes with gametophytic chromosome number and have
been produced in a variety of species using a variety of methods.” Although, the
significance of haploids in genetics has been recognized for long time, with the advent of
biotechnology it received renewed emphasis, so that the production of haploids become an
important component of biotechnology programmes in different countries. Although,
haploids could be produced following delayed pollination, irradiation of pollen,
temperature shocks, colchicines treatment and distant hybridization, the most important
methods currently being utilized include :
✓ Anther or pollen culture and ovule culture and
✓ Chromosome elimination following interspecific hybridization (bulbosum
technique).
What is Haploid ?
Gametes or germ cells are haploid cells (example: sperm and ova) containing only one set
(or n) number of chromosomes and autosomal or somatic cells are diploid cells containing
2n number of chromosomes. The number of chromosomes (n) differs in different
organisms. In humans a complete set (2n) comprises of 46 chromosomes.

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Haploid cells are a result of the process of meiosis, a type of reductional cell division in
which diploid cells divide to give rise to haploid germ cells or spores. During meiosis, a
diploid germ cell divides to give rise to four haploid cells in two rounds of cell division. This
process does not occur in organisms (example bacteria) that reproduce via asexual
processes like binary fission.
Fig: Haploid cells being produced via the process of meiosis. Note how each cell ends up having half
the number of chromosomes as the parent cell.
During the process of reproduction, haploid cells (male and female) unite to form
a diploid zygote. Cell growth is the result of mitosis; it is a process by which mother cells
divide to give rise to identical daughter cells with equal number of chromosomes. This
process differs slightly in different types of cells, animal cells undergoing "open" mitosis
with the breakdown of nuclear membrane, whereas organisms like fungi and yeast
undergo closed mitosis with an intact nuclear membrane.

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Production Process of Haploid
There are two ways to create haploids, and both involve the destructtion of genetic
material from one of the parents.The two ways are discuss in below:-
The first way is to "fertilize" eggs with sperm that have had their genetic material
destroyed by X- rays, gamma rays, chemicals, or UV irradiation. UV irradiation is probably
the best method to destroy sperm DNA, because the other methods can leave viable
chromosomal fragments which could produce partial diploids or reduce survival.
Additionally, UV irradiation is cheaper and safer. Sperm that have been treated this way do
not actually fertilize eggs, because their genetic material has been destroyed; instead, they
"activate" the egg. Once activated, an egg will begin embryological development, even
though the sperm carries no functional genes. Because the sperm contributes no genetic
material, the alleles contained in the egg haploid nucleus are the only genes that the
embryo has, and the haploid egg nucleus becomes the zygote's nucleus. These haploid
embryos are gyno- genetic haploids, because all genetic material comes from the embryo's
mother.
The second way to create haploids is to destroy the genetic material in eggs with X-rays
or gamma rays and to fertilize these eggs with normal sperm. Because the sperm's haploid
nucleus is the sole contributor to the zygote's genome, the embryo is a haploid. In this case,
the haploid embryo is an androgenetic. haploid, because all alleles come from the father.
Significance of Haploid Production:
The development and production of haploid is very important for the study of fundamental
and applied aspects of genetics in the higher organisms. Production of homozygous diploid
by doubling the chromosome number of haploid in vitro makes a pure line in single step
and such homozygous pure line is of great importance in breeding. Haploids are useful
because :-

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1. They carry only one allele of each gene. Thus any recessive mutation or
characteristic are apparent.
2. Organisms with lethal genes are eliminated from the gene pool.
3. One can produce homozygous diploid or polyploid plants/animals that may be
valuable in breeding.
4. Production of haploids shorten the time for inbreeding for superior hybrid
genotypes.
5. Haploids are interesting because they enable breeders to study certain
embryological genetic processes. On a practical level, it is important to know how to
produce haploids, because that is the first step in the production of gynogenetic and
androgenetic fish.
6. Productions of homozygous pure lines are the major goal in breeding strategy.
These are obtained by back crossing and inbreeding. These processes are however,
are time consuming. Once established, homozygous lines have potential for plant
improvement in several ways.
7. With the advent of anther culture, haploids can be obtained in a very short span of
time. Following chromosome diploitization, several numbers of homozygous
diploids can be produced in single generation.
8. The efficiency and potentialities of homozygous lines in plant improvement has long
been recognised. The homozygous lines are employed at least any phase of plant
breeding programme. Utilization of microspore derived homozygous lines has
resulted in the development of new cultivars in both rice and tobacco.
9. Haploids are ideal tools in cytological studies. During haploid generation,
chromosome reduction takes place from diploid to haploid status, which provides
unique opportunities for study of pairing relationship among the chromosomes.
Haploids can also be used in the production of monosomies, nullisomics and other
aneuploids and has been implicated in isolation of these in tobacco.

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10. Haploids has considerable potential in mutagenic study for which, free cells of
haploids in suspension could be employed for mutagenic studies and critically
assess the production of various biochemical mutants which often exhibit resistance
to environmental factors such as heat, cold, drought and more importantly pathogen
resistant.
11. Anther culture provides a unique opportunity to shortening breeding cycle and
recovers several types of new gene combinations, consequently helps in plant
improvement. In addition, isolated microspore culture system is basically a model
system for mutagenesis studies and screening for mutants becomes available.
Applications of Haploids:
In Vitro production of haploids can solve some problems in genetic studies since gene
action is readily manifested due to a single allelic gene present in chromosome of entire
genome.Some Application of Haploid are listed below:-
Releasing New Varieties through F1 Double –haploid System
Selection of Mutants Resistance to Diseases:
Developing Asexual Lines of Tree Perennial Species:
Transfer of Desired Alien Gene:
Establishment of Haploids and Diploid Cell Lines of Pollen Plant:
Mutagenesis:
Production of super male of Asparagus officinalis

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Conclusion:
Although, the significance of haploids in genetics has been recognized for long time, with
the advent of biotechnology it received renewed emphasis, so that the production of
haploids become an important component of biotechnology programmes in different
countries. The development and production of haploid is very important for the study of
fundamental and applied aspects of genetics in the higher organisms. Production of
homozygous diploid by doubling the chromosome number of haploid in vitro makes a pure
line in single step and such homozygous pure line is of great importance in breeding. This
review has summarized a long and fascinating history of haploids in higher plants &
Animals. Their occurrence developed gradually from being a sporadic and random
process in vivo to one which could be predicted, especially with the discovery of efficient in
vitro methods for the induction of sporophytes from gametophytic cells. Their value has
also increased in many areas of fundamental plant science, but most particularly in the
context of plant breeding and their place in the route to homozygous lines and thence to
pure cultivars and F1 hybrids. This process of exploitation can be expected to continue in
the race to improve the efficiency and yield of crop plants at a time of increasing challenge
to maintain food security
References:
[1] Tave, Douglas (1993) .Genetics for Fish Hatchery Managers (2. ed).Publishers ISBN
978-0-442-00417-0
[2] Bhojwani, S. S.; Razdan, M. K. (1996). Plant tissue culture: theory and practice (Revised
ed.). Elsevier. ISBN 0-444-81623-2
[3] Razdan, M. K. (2003). Introduction to plant tissue culture (2. ed). Enfield, NH [u.a.]:
oxford Publishers. ISBN 1-57808-237-4

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[4] https://www.diffen.com/difference/Diploid_vs_Haploid
[5] https://www.biologydiscussion.com/genetics/significance-of-haploids-genetics/71830