Vegetable breeding, polyploidy,

1. Submitted By:-
Sushil Kumar
M.Sc Vegetables Science
USE OF POLYPLOIDY IN VEGETABLE CROPS

2. INTRODUCTION :-
• An organism having more than two sets of homologous chromosomes is
known as polyploid and the phenomenon polyploidy. It was discovered by
Lutz. It is rarely found in animals but is of general occurrence in plants. A
survey of the chromosome numbers of the species in a family shows that
these species generally fall in to polyploid series e.g., 2n, 3n, 4n, 5n, 6n etc.
• triploid (three sets; 3x), for example seedless watermelons,
• tetraploid (four sets; 4x)for example potato
• pentaploid (five sets; 5x)
• hexaploid (six sets; 6x)
• heptaploid (seven sets; 7x)
• octaploid (eight sets; 8x)

3. TYPES OF POLYPLOIDY :-
1. Euploidy—individual has one or more whole sets of chromosomes with
each chromosome represented once in each set. There are three main
kinds of euploidy.
• Haploidy- individual with half (n=x) of the somatic cell chromosome
number.
• Diploidy- individual with two sets of the basic, complete genome
(2n=2x).
• Polyploidy- individual with more than two basic, complete sets of
chromosomes in its somatic cells. Among polyploids, there are two main
types:

4. CONTINUED…..
• Autoploidy—individual has more than two complete
chromosome sets from a singlegenome. Also known as
autopolyploidy
• Alloploidy—individual has two or more genomes
contributed from different parental species in their ancestral
lineage. Also known as allopolyploidy. Most naturally
occurring polyploids are alloploids.
• Eg:- Raphanobrassica

5. • 2. Aneuploidy— organism has a partial set of chromosomes due
to addition or deletion of specific chromosome(s). or one or
more chromosome sets. It is a state in which the number
of chromosomes is not an exact multiple of the haploid number

6. CONTINUED….

7. INDUCTION OF POLYPLOIDY:-
Polyploids were successfully produced by treating plant parts with:-
• Colchicine
• Colchamine
• Oryzalin
• Colcemid
• Trifluralin
• Amiprophosmethyl etc.

8. POLYPLOIDY INDUCTION:-
Colchicine Treatment :-
• A chemical that is commonly used to artificially double
chromosomes.
• Broadened genetic base. Alloploids (also known as amphiploids)
behave like diploids and result in new species.

9. ARTIFICIAL ALLOPOLYPLOID:
• 1. Raphanobrassica: This a classical example of artificially synthesizesd
alloploid. This was developed between radish and cabbage by Russian
geneticist Karpechenko in 1928.

10. • He wanted to develop a fertile hybrid between these two
species with roots of radish and leaves of cabbage. But he got
a fertile amphidiploid (4n = 36) by spontaneous chromosome
doubling which unfortunately had roots of cabbage and leaves
of radish. Thus it was of no use.

11. • An Infertile triploid created from 4X and 2X parents
SEEDLESS WATERMELON:-

12. SUGAR BABY (WATER MELON):-

13. • Teraploid potato: Crosses between diploid parents with variable
expressivity of 2n gametes generally produce tetraploid and
diploid offspring (Ortiz and Peloquin, 1991b)
• Tetraploid turnip: Vegetative growth of tetraploid turnip is much
greater than diploid and commercially available in Europe
(Poehlman and Sleper, 2006).

14. APPLICATION OF POLYPLOIDY:-
• Mutation breeding
• Seedless fruits
• Bridge crossing
• Ornamental and forage breeding
• Disease resistance through aneuploidy
• Industrial applications of polyploidy

15. ADVANTAGES:-
• Enlargement and Increased Vigor
• Creation of Sterile Triploids
• Restoring Fertility in Hybrids
• Overcoming Barriers in Hybridization
• Enhancing Pest Resistance and Stress Tolerance

16. DRAWBACKS:-
• Inbreeding in polyploids
• Effect of polyploidy on sterility
• Effect of polyploidy on inheritance and population
genetics

17. REFERENCES:-
• https://en.wikipedia.org/wiki/Polyploid
• http://slideplayer.com/
• http://www.slideshare.net/
• http://www.biologydiscussion.com/
• http://www.nature.com/scitable/nated/topicpage/polyploidy-1552814

18. THANK YOU……