This document discusses polyploidy and its applications in various ornamental crops. It defines polyploidy as having more than two paired sets of chromosomes. There are two types: autopolyploidy which involves more than two copies of a single genome, and allopolyploidy which involves two or more genomes with each present in two copies. The document outlines traits that make species suitable for inducing polyploidy and lists effects of polyploidy. It then discusses specific examples of polyploidy in various ornamental crops like rose, gladiolus, dianthus, chrysanthemum, anthurium, dahlia, gerbera and jasmine. It concludes by

1. Course instructors:
DR. K.V. PRASAD
DR.DVS.RAJU
DR.KANWAR PAL

2. The presence of more than two paired sets
of chromosomes.
Numerical change in a whole set of
chromosomes.
Triploid (3N), tetraploid (4N), pentaploid
(5N), hexaploid (6N)

3. The polyploidy is of two
types
 Autopolyploidy
more than two copies of a
single genome.
 Allopolyploidy
two or more genomes and
each genome ordinarily present
in 2 copies
Autopolyploidy
•within a species
•multiplication of the
same set of
chromosomes
• Induced artificially by
colchicine Ex-
Antirrhinum, Cosmos,
Dimorphotheca

4. Traits in species , suited for
induction of polypoidy- by dewey
•Should have low CN
•Economic part should be vegetative.
•Should be cross- pollinated
•Should be perennial in habitat.
•Have ability to reproduce vegetatively.

5. Effect of polyploidy:
1.. Increased fruit weight, fruit size, seed size, crop
load, flower size etc.
2.. Reduction in fertility (in odd ploidy level individuals).
3.. Change in growth pattern.
4.. Can be used to create higher diversity.
5.. Greater ability to colonize new habitats than diploid
ancestors.
6.. increase blooming period
(marigold, Begonia, ageratum)

6. Alloployploidy-
•Chromosome doubling after hybridization of 2
sps
• Interspecific polyploidy
•Caused by hybridization followed by
chromosome doubling e.g., AABB, AABBCC
•To restore fertility in inter-specific crosses by
spontaneous doubling of chromosome
(Begonia, Impatians, Kalanchoe)

7. Haploidy:
•Bears only one set of chromosomes
•Haploids of higher plants are sterile
•Producing pure homozygous lines for
breeding programs.
•Such plants are developed through a
culture technique developed by Guha and
Maheshwari
• Gynogenic haploids

8. Application in crop
improvement:
-Tracing the origin of crop sps.
-Speciation & evolution
-Interspecific gene transfer.
-As a bridging cross

9. Polyploidy in ornamental crops:

10.  ROSE
CN from 2n=14 to 56
Early miniatures diploid, later
ones, tetraploid.
Hybrid teas and flouribundas
generally tetraploids
Sterility of some diploid
Interspecific hybrids arise
through genomic differences,
chromosome no may be
expected to increase fertility.

11. Thus sterile diploid R. rugosa x wichuriana ‘Max Graf’
spontaneously produced a tetraploid seedling, R. kordessi
Doubling of chromosome being tried
For sterile hybrids & diploid species to avoid production of
sterile triploids after cross with tetraploid cultivars.
Polyploidy induced in species & F1 interspecific hybrids by
colchicine to shoots of seedlings
The frequency of tetraploid was low
Chimerism complicating factor
In-vitro, controlled application of spindle inhibitoRS

12. Gladiolus (x=15)
South african species-diploid
Eurasian and central African
species-tetraploid
 Sterile triploids and pentaploids
found
Indicates diploid-tetraploid and
tetraploid-hexaploid crosses
Highest chromosome no
G.communis
Some tripoids and pentaploids are
fertile
Ferlite aneuploids

13. Dianthus species-
• x = 15 (2n=30 to 180)
•D. chinensis- tetraploid;
D.caryophyllus-diploid
•D. gratianopolitanus- both
tetraploid and hexaploid
•Many desirable plant characteristics
related to plant ploidy levels
• Mixoploidy in several organs
from D. caryophyllus
• Positive correlation between
endopolyploidy, cell and petal size

14. Chrysanthemum-(x=9)
•CN from 2x to 25x
•2n=36, 45, 47, 51, 75 by T.N. Khushoo
• Intraspecies and intrapopulation
variations in ploidy
•C. indicum - 2x,4x & 6x
•C. zawadskii - 4x & 6x
• Polyploids widely distributed
•Evolution & regulation of flower size of
large-flower population possible.
•evidence of low ploidy in large-flower
chrysanthemum

15. •Anthurium
(2n=20 to 124)
•Mostly diploid, some polyploid also
present
•A.Andreanum, A.magnificum & A.
hookeri- diploid
•A.digitatum & A.wallism –tetraploid;
A.Scandens- triploid.
•chloroplast number in the guard cell
convenient & reliable indicator of ploidy
level in anthurium.
•Micropropagation of A. scherzerianum
poses very little risk in ploidy changes

16. Dahlia
• 2n=32, others 2n=64
•Sorenson- 2n=32 species were
diploid and 2n=64 species
tetraploid
•Lawrence (1929) suggested that
the 2n=32 species were
allotetraploids, arising from hybrids
between now-extinct diploids with
2n=16.
•Garden dahlia (D. vŠ ariabilis)
with 2n=64, a hybrid that
combined the genomes of two
species
•It is an autoallopolyploid, rather
than an allooctoploid

17. Gerbera
•2n=50
•G jamesoni=tetraploid
•Tetraploid plantlets - slower
proliferation, higher vigour and
thickened broad leaves.
•Tetraploid plants developed larger
flowers, longer stalks, and have
improved vase-life
•No of chloroplast present in the
stomata of guard cell is indicator
•Haploid use for development of new
varieties

18. •Jasmine(x=13)
• Important role in origin of new cultivars
in essential oil bearing plants.
•Spontaneous triploid in J. sambac & J.
autumnale(Sharma and Sharma), J.
grandiflorum( Murthy and Khanna)
• Spontaneous tetraploidy in
J.calophyllum (Dutta)
• Triploidy in J.grandiflorum increase
concrete content and thereby hold
promise as useful avenue for
improvement of this crop.
•Attempt to induce tetraploidy in
Jasmine.
•Induced tetraploidy in J. grandiflorum
did not reveal superiority.

19. Important polyploid
varieties in flower crops:
Rose –pusa mohini, aneuploid(3n+1)
Eva and J.G. Thornton-
tetraploid
Marigold –nugget, triploid
Zenith Mixed, triploid
Bougainvillea –Begum
sikandar, aneuploid(3n-2)
Mary
palmer,
Tetraploid
Amaryllis -Samrat, tetraploid