Cross pollination in plants

cross pollination, mechanisms, agents,adaptation,importance etc.

1. Sub.:-Fundamentals of Plant Breeding
Course No. :-APB-5211
Credit hours:-3(2+1)
Lec. Topic :-Cross Pollination and its types.
Presented by:-
Lt. RoshanParihar, Asstt. Professor
Deptt. of Genetics & Plant Breeding
Indira Gandhi Krishi Vishwavidyalaya
Raipur, C.G.
BTC College of Agriculture & Research Station
,Sarkanda, Bilaspur,(CG)-495001

2. Crosspollination

3. •Pollen from the anther of one plant is
transferred to the the stigma of a
different plant
Cross pollination

4. Bee goes intoflower

6. Bee transports into anotherflower

8. Cross-Pollination
•Insects other than bees may also cross-pollinate
such as:
Butterflies
Mosquitos
Caterpillars

9. CROSSPOLLINATION:
When pollen grains of the flower of one plant are
transferred to the stigma of the flower on the other
plant of same or different species is called as cross
pollination.
It occurs in unisexual as well as bisexual flowers.
It is common in nature.
Xenogamy Hybridization
Cross pollination

10. Xenogamy:
The process in which the pollen grains are
transferred to the flowerof
other plant of the same species is known as
xenogamy.
Eg-Papaya,Castor.

11. Hybridization:
The process in which the pollen grains are
transferred to the flowerof
other plant of the different species or variety is
known ashybridization.
It is mostly doneartificially.

12. Feature Reason
small petals, often brown or dull
green
no need to attract insects
no scent no need to attract insects
no nectar no need to attract insects
pollen produced in great
quantities
because most does not reach
another flower
pollen very light and smooth so it can be blown in the wind
anthers loosely attached and dangle outto release pollen into the
wind
stigma hangs outside the flower to catch the drifting pollen
stigma feathery or net like to catch the drifting pollen
Wind PollinatedFlowers

13. Feature Reason
large, brightly coloured petals to attract insects
often sweetly scented to attract insects
usually contain nectar to attract insects
moderate quantity of pollen less wastage than with wind
pollination
pollen often sticky or spiky to stick to insects
anthers firm and inside flower to brush against insects
stigma inside the flower so that the insect brushes against it
stigma has sticky coating pollen sticks to it
Insect PollinatedFlowers

15. Wind/InsectPollination

16. Adaptations for crosspollination
1.Dicliny(Unisexuality):-presence of unisexual flower.
2.Dichogamy:-stamens and carpels of flower do not
mature at same time
•Protandry:-Anther of flower mature earlier than
carpel. ex salvia & sun flower
•Protogyny:-the carpel of flower mature earlier than
stamens. Bajra
3.Chasmogamyor anthesis:-opening of floral bud in the
form of a flower.

17. ADVANTAGES-
•New varieties of plants can be produced.
•The progeny shows advanced vigour.
•Off springs are more viable and resistant.
•It is responsible for genetic recombination.
•It leads in production of seeds in self sterile
plants
•It introduces new desirable characters and eliminated
undesired one’s.
DISADVANTAGES-
•More wastage of pollen grain is seen.
•Pollinating agents are required.
•It is not a sure method of pollination.
•Genetic purity is not maintained.
•Plants have to develop various devices to
attract agents for pollination.
•It is not an economical method.

18. METHODS TO ENSURE CROSS POLLINATION
Dichogamy :
Anthers and stigmas mature at different
times in a bisexual flower so as to prevent
self pollination.
-Protandry Anthers mature earlier than
stigma of the same flower. Their pollen
grains become available to stigmas of the
older flowers, e.g., Sunflower, Salvia,
-Protogyny
Stigmas mature earlier so that they get
pollinated before the anthers of the same
flower develop pollen grains, e.g., Mirabilis
jalapa (Four O’Clock), Gloriosa, Plantago.

19. Herkogamy :
In some bisexual flowers the
structure of male & female sex
organs itself prove a barrier to self
pollination.
Self Sterility (Self
Incompatibility):
Pollen grains of a flower do not
germinate on the stigma of the
same flower due to presence of
similar self sterile gene (S,S
3 in
pistil and S
1 or S
3 in pollen grain),
e.g., Tobacco, Potato, Crucifers.

20. Heterostyly :
There are 2 or 3 types of flowers with different heights of styles and stamens.
(a)Diheterostyly (Dimorphic Heterostyly):
There are two types of flowers
-Pin eyed (long style and short stamens)
-Thrum eyed (short style and long stamens), e.g., Primula (Primrose),
(b) Triheterostyly (Trimorphic Heterostyly or tristyly):
There are three types of flowers with differentheights of styles.
e.g., Lythrum. Pollination occurs between anthers and stigmas of the same
height present in different flowers

21. ARTIFICIALPOLLINATION OR HYBRIDIZATION
This technique is used for the purpose of
Hybridization.
It involves pollination of desired female parents with
pollen from the desired male parent, taking all
precautions to prevent contamination of stigma with
undesired pollen.
In unisexual plants the procedure is simple but its
complicated in bisexual ones.
2 processes that takes place in bisexual flower :
-Emasculation
-Bagging

23. IMPORTANCE OF CROSSPOLLINATION:
ADVANTAGES
Cross pollination
introduces genetic re-
combinations and hence
variations in the progeny.
Cross pollination
increases the adaptability
of the offspring towards
changes in the
environment.
It makes the organisms
better fitted in the struggle
for existence.
The plants produced
through cross pollination are
more resistant to diseases.
DISADVANTAGES
•A factor of chance is always
involved in cross .pollination.
•It is less economical.
•Some undesirable characters
may creep in the race.
•The very good characters of the
race are likely to be spoiled.

24. COEVOLUTION OF FLOWER AND ITS POLLINATOR SPECIES:
Coevolution is the evolution in two species that interact
extensively with one another so that each acts as a major
force of natural selection on the other.
When one evolves a new feature or modifies itself, the
other evolves new adaptations in response of it.
This constant mutual feed back modification between the two
species is known as coevolution.
The coevolution of the flower and its pollinator species are
tightly linked with one another.

25. Disa niveais a rare orchid found only in a few places in South Africa,
and until Johnson came to study it, no one knew how it was
pollinated. After a lot of patient orchid-watching, he and his colleagues
discovered that it is visited exclusively by the fly shown in the picture.
Its proboscis is well-matched to the length of the orchid, and the
orchid grows pollen in just the right place so that they get stuck to the
fly. You can see them in this picture–the two dangling yellow packets
on the fly’s snout. This fly is named as Orchid fly.

26. Pollination is a vital process of nature.
It is estimated that ¾ of our staple crops, and 1/3 of all food crops
require pollination.
For the fruit seeds to develop, pollen has to be transferred
between two flowers of the same species, which then fertilizes the
flower and allows the production of healthy seeds on the plant.
Pollinators play an essential role in pollination as they work as
medium for pollination to be occur.
he most widely known pollinators are honey bees. Honey bees
are responsible for the pollination and thus production of $19 billion
worth of food crops each year, just in the United States alone!
 There are many other pollinators that are just as vital
to food crop productions and plant reproduction as honey bees, but
aren’t as well known such as wasps, moths, flies, butterflies,
beetles, bats, birds, and ants.