Triploidy ...............................pptx

1. TRIPLOIDY
1

2. Content
1. Triploidy
2. Importance of triploid plants
3. Conventional production of triploid plants
4. Endosperm culture
5. Advantages
6. Limitations
2

3. TRIPLOIDY
• Triploidy is a genetic condition characterized
by the presence of three sets of
chromosomes in an organism’s cells instead
of the usual two.
• Triploid plants have larger organs, greater
biomass, and strong stress resistance by
preserving relatively larger amounts of
photosynthetic energy.
• Triploid plants are valued for the seedless
fruits. E.g., seedless banana, watermelon
etc.
Triploidy…
3

4. Importance of triploid plants
Seedless Fruit Production
• One of the primary applications of triploidy in plants is the production of
seedless fruits.
• For example, seedless watermelons, grapes, and bananas are often triploid
varieties.
Triploidy…
4

5. Increased Vigor and Growth
• Triploid plants are typically sterile, meaning they cannot produce viable seeds.
• This sterility is advantageous in fruit production, as it eliminates the need for
seeds, enhancing the fruit’s market value and desirability.
Neutralizing invasive plants
• The undesirable spread of non-native invasive crop and horticultural plants into
natural areas can also be reduced or eliminated by the use of triploids, because
they tend to be sterile and seedless.
Triploidy…
5

6. • Triploid production increases the size of somatic cells and guard cells and
increases chloroplast number, which results in strengthening photosynthesis.
• Therefore, many triploid plants are relatively more vigorous; have short
internodes; broad, thick, dark green leaves, resulting in greater biomass or crop
yield per plant.
Triploidy…
6

7. Prolonging flowering period
• Flowers of triploid plants are generally larger and more colorful than those of
their diploid counterparts partly because the energy that is normally devoted
to seed formation is used for flowers or other organs.
• Triploid flowers often have longer shelf life.
Genetic Research
• Studying triploid plants provides valuable insights into genetics and
chromosomal behavior.
• Understanding how triploidy influences gene expression and development can
contribute to broader advancements in plant genetics.
Triploidy…
7

8. • Some triploid plants demonstrate improved resistance to certain diseases.
• Triploid plants may exhibit enhanced tolerance to environmental stresses
such as drought, heat, or soil salinity. This resilience makes them well-suited
for cultivation in challenging conditions.
• Triploid plants can result from crossing two different diploid varieties. The
hybrid vigor, or heterosis, observed in triploid offspring often leads to plants
with superior qualities, including better disease resistance, adaptability, and
overall robustness.
Triploidy…
8

9. • Triploid plants often exhibit enhanced fruit quality.
• This is of great value in tree species, which are grown for biomass production
such as acacia, sandalwood and Tea.
• Triploid plants are used in ornamental horticulture to create new and unique
flower varieties.
Triploidy…
9

10. Conventional production of Triploid plants
Natural selection
• Fertilization of unreduced gamete (2x) with the normal
gamete (n) results in triploids.
• Environmental stress variables may stimulate production of
unreduced gametes in diploids.
• Rare in nature because of inviable seeds and hence no
progeny.
• Banana is a typical example of naturally existing triploid.
Triploidy…
10

11. • Triploidy is encountered occasionally in natural populations of flowering
plants containing diploid (2n) and tetraploid (4n) plants.
• Triploids arise by natural crosses between diploid and tetraploid plants in the
same population.
• However, there are many examples of triploid strains of cultivated plants that
have been induced artificially by crossing diploid and tetraploid parental
strains.
Triploidy…
11

12. Artificial hybridization
• Sexual hybridization of diploid and tetraploids is the most common method
i.e. 2x X 4x or 4x X 2x.
• Chromosome doubling can be achieved by spindle inhibitors or protoplast
fusion.
• Colchicine is commonly used to disrupts spindle fiber formation during cell
division, leading to chromosome doubling in treated cell.
Triploidy…
12

13. • The diploid plants are treated with colchicine to get
tetraploid plant (4n).
• The tetraploid and diploids are crossed.
• Thus triploid plant was formed.
• Triploid efficiency depends upon several factors like
Pollen viability, compatibility between the parents or
the frequency of unreduced gametes.
Triploidy…
13

14. Triploidy…
14

15. Triploidy…
15

16. Endosperm culture
• Culture of endosperm to regenerate whole plants
under in vitro condition is termed as endosperm
culture.
• Endosperm is formed in most cases by the fusion of
two polar nuclei with one of the male gamete.
• It is the main source of reserve food for the
developing embryo.
Triploidy…
16

17. Endosperm
• Short lived
• Unorganized
• Triploid
• Stores reserve
food materials
• Provides nutrition
during embryo
development and
seed germination
Triploidy…
17

18. • Endosperm is generally short lived-structure and is consumed during the
development of embryo (exalbuminous seed).
• In plants like Castor, it exists as a massive tissue even in the mature seed
(albuminous seed).
• Seedless triploid plants can be produced by endosperm culture.
• The first attempt on endosperm culture was made by La Duel (1949).
Triploidy…
18

19. TYPES OF ENDOSPERM CULTURE
1. Mature endosperm culture
It is the in vitro development of isolated mature endosperm from ripen
endospermic seed on suitable culture medium to obtain triploid plantlet is
called mature endosperm culture.
2. Immature endosperm culture
It is the in vitro development of isolated immature endosperm isolated at
precise stage from immature seed, cultured on suitable culture medium to
obtain triploid plantlet is called immature endosperm culture.
19

20. STEPS IN ENDOSPERM CULTURE
• It consist of mainly 3 steps:
1. The immature or mature seeds are dissected under aseptic conditions and
endosperms along with embryos are excised.
2. Excised endosperms are cultured on a suitable medium and embryos are removed
after initial stage.
3. Callus followed by embryogenesis or shoot bud differentiation.
4. Complete plant formation.
Triploidy…
20

21. 1. Explant source
• In most of the cereals, mature endosperm does not respond to
cultural conditions. It is therefore, excised at proper period of
development.
• In some families association of embryo tissue in initial stages seems
essential for proliferation of mature endosperm. In such cases, entire
seeds are used as explant. Immature seeds provide explant for non-
endospermic seeds.

22. 2. Inoculation of explant
• For in vitro culture mature endosperm, seeds having massive endosperm are
decoated, surface sterilized with suitable disinfectant and after 2-3 washings with
sterile distilled water, planted on the nutrient medium.
• For in vitro culture of an immature endosperm, the entire seed or kernel is
surface sterilized and the endosperm tissue is excised under aseptic conditions. In
cereals, top of kernel or immature ovaries (micropyle end) are cut off with a
sterile knife and exposed endosperm squeezed out and placed on the callus
induction nutrient medium.
• The basal medium is supplemented with tomato juice, yeast extract, grape juice.
Sucrose (2-4%) is used as a source of carbohydrates. In some cases, addition of
2,4- D or IAA, cytokinin necessary.

23. 3. Incubation/ maintenance of culture
To induce callus, the endosperm cultures are maintained darkness or diffused light.
Differentiation take place when calli are transferred to bright light (2000 lux – 4000
lux) and 25°C temperature
4. Shoot bud differentiation or embryogenesis
• Plantlet formation from endosperm callus maturation follow organogenic or
embryogenic mode of development.
• Embryo differentiation occurs when the proliferated tissue is transferred from
callusing to basal medium with or without gibberellins. So culturing carried out
up to complete development of plantlet.
5. plantlet developed are hardened in green house by transferring in vermiculture
media and maintaining proper humidity.

24. Triploidy…

25. Triploidy…

26. Advantages
1. A novel method for triploid plant production
• This technique has enabled the production of triploid plants. Triploid plants are self
sterile and usually seedless.
• Endosperm culture technique is applied to economically important cultivars for
raising superior triploid plants.
• The trait increases the edibility of fruits.
• E.g., Apple, Banana, Mulberry, Sugar beet, Peach, Watermelon etc., which are
commercially important for their edible parts.
Triploidy…

27. 2. Increases yield of timber and fuel
• In timber and fuel yielding plants, triploids show better performance over their
relative diploids and tetraploids.
3. Rescuing embryos from incompatible crosses
• The most useful and popular application of embryo cultures is to raise rare
hybrids by rescuing embryos from incompatible crosses.
4. Overcoming dormancy and shortening breeding cycle
• Long, periods of dormancy in seeds delay breeding works, especially in
horticultural and crop plants. Using embryo cultures techniques the breeding
cycle can be shortened in these plants.
Triploidy…

28. 5. Overcoming seed sterility
• In early ripening fruit cultivars, seed do not germinate because their embryos
are still immature.
• Using the embryo culture method it is possible to raise seedling from sterile
seeds of early ripening stone fruits, peach, apricot and plum.
6. To exploit in the biosynthesis of some natural products. E.g.:- Cultured
endosperm of coffee synthesizes caffeine. The level of this alkaloid in callus is
synthesized by three times after two weeks and by 6 times after 4-5 weeks.
7. Various trisomic developed from triploids may also be useful in gene mapping
for cytogenetic studies.
Triploidy…

29. Limitations
1. Triploid production through endosperm culture technique has been successful
only in a limited number of species. In majority of species mature endosperm
proliferation resulted in a callus tissue of unlimited growth. But the induction
of organogenesis in endosperm culture has always being a challenging
problem.
2. In cereals (or) crops where grains (or) seeds are used, triploids are undesirable.
Triploidy…

30. Reference
1. Bhojwani, S. S., & Razdan, M. K. (1986). Plant tissue culture: theory and
practice. Elsevier.
2. De K.K. (2003). Plant Tissue Culture. New Central Book agency (P) Ltd, Calcutta.
3. Razdan M.K. (2000). An introduction to plant tissue Culture. Oxford& IBH
publishing Co. Pvt. Ltd. New Delhi, Calcutta.
4. Wang, X., Cheng, Z. M., Zhi, S., & Xu, F. (2016). Breeding triploid plants: a
review. Czech Journal of Genetics and Plant Breeding, 52(2), 41-54.
5. https://www.ehow.com/info_12013003_triploid-plants.html

31. Thankyou