Pollination and Fruit setting
Week - 3
Lecture 1

Flower
Flower is a shoot of determinate growth with modified
leaves that is supported by short stem
Flower parts
Sepals/calyx
Petals/corolla
Androecium
Gynoecium
Perianth
Pedicle
Peduncle
Brackets
Receptacle/thalamus
Enlarged apex of the flower stalk or head
of the pedicle from where the flower
parts arise

• Perianth: External row of petals or sepals
• Pedicle : stalk of flower is called …
• Peduncle: stalk of inflorescence
• Bracts: A bract is special leaf, which bears a
flower or cluster of in its axil. Chief function is to
protect the flower-buds from the sun and rain
• Thalamus: Enlarged apex of the flower stalk or
head of the pedicle from where the flower parts
arise

Sepal
Petal
Ovary
Stigma
Filament
Anther
Pedicle
Receptacle
Style

Types of flowers
Complete flower (A complete flower is a
flower that has all four parts of the
flower (sepals, petals….. )
Example: Citrus, Apple, Tomato, Peach, Plum, Pear
Incomplete flowerA flower lacking sepals,
petals, stamens, or pistils.
Example: Date palm (with out petal)

Types of flowers
• Perfect flower (both sex organs )
• Example: Citrus, Apple, Tomato,
Peach, Plum, Pear
• Imperfect flower (a unisexual flower with
only stamens or only pistils )
• Example: Papaya, date palm

Types of flowers
Pistillate
Example: Date palm
Staminate
Example: Walnut, Pecan nut (Catkins)
Hermaphrodite
Example: Citrus, Guava, Apple
Solitary (flower singly)
Example: Peach,
Clustered flower (in group)
Example: Mango, Apple, pear, grapes

Determinate flowers:
Inflorescence in which terminal flowers open first.
Example: Apple
Indeterminate flowers:
The inflorescence in which the basal flowers open
first and flower bud continue to develop. Example:
Tomato, Pear, Cucumber
Hypogynous:
If the stamens, petals and sepals are attached to the
receptacle below the ovary the ovary is superior and
flower is hypogynous. Example: Citrus, Grapes, Kiwi
fruit
Types of flowers

Ovary Position

Ovary Position

Zygomorphic:
if flower can be divided into two equal parts by
cutting it into only one longitudinal plane.

Basal placental arrangement:
Ovules are attached at the base of
ovary in side the locules. Example:
Avocado
Apical placental arrangement:
Ovules are attached at the apex of
ovary in side the locules. Example:
Peach
Placental arrangement
Attachment of ovule to the ovary walls
through strand or filament is called placental
arrangement

Placentation
Peach Avocado

Embryo Sac:
Cavity inside the ovule is called embryo sac
Integument:
Walls of the mature embryo. These two walls form
the outer covering of seed. (Testa and Seed Coat).
Example: Pear, Blue berry

Pollination
Successful transfer of pollen from anther of a
stamen to the receptive stigma of an overy is
known as --------
 Availability of adequate and viable pollen
 Efficient transfer of pollen when stigma is most
receptive
 Pollen tube must grow & enter the embryo sac
 Union of male and female gametes
Stimulus for fruit development

Transfer of pollen-grains on stigma with in the
same flower or an other flower of the different
plant of the same variety.
It occurs in homogamous flower; bisexual flowers in
which pollen grains are shed when the stigmas are
ready for reception
Example Peach, Avocado, Fig
Self pollination ( autogamy)

Self fertility/self fruitfulness
Ability to set and yield a commercial crop
with its own pollen.
Self sterility/ self unfruitfulness
Inability to set and yield a commercial
crop with its own pollen.

Pollination and fruit setting problems
1. Flower opening
2. Pollen dehiscence
3. Pistil receptivity
1- Flower opening
 Day lily flower opening in early in morning 6-7 am to 8-9
pm. Total duration of flower opening is 12-14 hrs. Flower
open at morning and close evening
 Poppy flower open for 2 days
 Apple flower open for 2-5 days
 Orchids flower open for 80 days
Flower opening in different plant ranges from few hours to
many days

2- Pistil receptivity
Receptivity of guava pistil is 48 hours after flower opening
Date palm about 4 days after opening of spathe and about
after 8 days receptivity finishes
Fertilization in plum takes place even after 7 days of flower
opening
Guava stigma remain receptive for 2 days
In Mango stigma remain receptive for 4 hours
Mostly those flowers which have abundance of pollen are
wind pollinated and do not open for longer duration
Whilst those flowers have little pollen remain open for
larger duration and are insect pollinated

3- Pollen dehiscence
The rupturing of anther either length wise or apically and to
remove the pollen is called pollen dehiscence
Pollen dehiscence and stigma receptivity occurs
simultaneously
But it is not universal truth that during blooming the stigma
will always remain receptive
Temperature and humidity are two factors which effect pollen
dehiscence
Under normal conditions pollen viability ranges form few hrs
to few days
Guava 4 hrs

Cross pollination( allogamy)
• The transfer of pollen from anther of the
flower of one variety to the stigma of
flower of another variety is known as cross
pollination

Prerequisites of cross pollination
• Self incompatibility
• Sterility
• Dichogamy (non-synchronous maturation
of pollen grains and ovules in
hermaphrodite or unisexual flowers on a
single plant)
• Heterostyly ( variation in length style 0

Fecundation/Fertilization
Union of male and female gametes

Fruit setting
Fruit setting refers to the initial and first
appreciable swelling of ovary occurring shortly
after the period of petal fall. Its is generally
accompanied by some thickening of pedicle or
peduncle.
Vegetative response to pollination
and fruit setting
Flower that has not set are turned yellow,
withered and fall off.
Fertilization follow the growth and development
of embryo and endosperm with in the ovary and
surrounding ovary walls, some time torus and
other adjoining tissues.

Types of drops
First drop or Blossom drop:
Occurs soon after blooming. Usually flowers with
defective parts drop.
Second drop or initial fruit drop
June drop (Button drop)
Preharvest fruit drop:
In consist of drop of un-pollinated flower and
very young fruits.
Due to any abiotic or environmental stress. Small
button size fruit drop. Some time in citrus called
as natural load sharing
Fruit is mature and about to ripe. Economic loss
to the grower.