pollination of crops slides

R. C. SihagDepartment of Zoology & AquacultureCCS Haryana Agricultural University,

Hisar

Structure of a Typical Flower

Selfing vs. Out Crossing

POLLINATION

TWO COMPONENTS

POLLINATOR PLANT

POLLINATOR LEVEL PLANT LEVEL

ENVIRONMENTAL FACTORS

Dynamic component (Actor) Stationary Component (Stage)

POLLINATING AGENTS

Abiotic Biotic

Gravity Water Air Insects Birds Mammals(Bats)

(Geophily) (Hydrophily) (Anemophily) (Entomophily)(Ornithophily) (Chiropterophily)

EFFECTIVITY OF

WATER MOVEMENT & GRAVITY

Very Low and Limited

EFFECTIVITY OF ANEMOPHILY

Pe = m x as/ af

where

Pe = Pollen effectivity

m = total pollen mass

as = stigmatic surface area

af = total filtration area

For 1 sq mm of stigmatic surface area = 1 million pollen grains in 1 sq meter area required

Effectivity of Zoophily

Very high

But

Depends upon several factors

REPRODUCTIVE BARRIERS IN PLANTS

• 1. Self-incompatibility

• 2 Protandry/protogyny

• 3. Unisexuality

• 4. Heterostyly

SP

NO

1. Self-incompatibility

CP YES

SEED SET

Brassica rapa

Brassica campestris

No seeds

2. PROTARDRY / PROTOGYNY

MATURE NOT MATURE /NOT RECEPTIVE

NOT MATURE RECEPTIVE

No seeds

SP

SP

♀♂

♂ ♀

Onion

Unisexuality

i) FLOWERES ARE UNISEXUALe.g. CUCURBITS

ii) PLANTS ARE UNISEXUALe.g. PAPAYA

Cucurbit crops

OILSEED CROPS

• 1. Toria SI , CP

• 2. Brown Sarson SI, CP

• 3. Taramira SI, CP

• 4. Sunflower SI, CP

• 5. Safflower SC, CP

• 6. Castor SC, CP

VEGETABLE CROPS

1. Radish SI, CP2. Turnip SI, CP3. Cauliflower SI, CP4. Carrot PT, CP

5. Cucurbits US, CP6. Tomato SC, CP7. Brinjal SC, CP

8. Bhindi SC, CP

HORTICULTURAL CROPS

1. APPLE SI, CP

2. PEACH SI, CP

3. PEAR SI, CP

4. PLUM SI, CP

5. GAUVA Partial SI, CP

6. GRAPES Partial SI, PT, CP

7. CITRUS SI,SC,CP

8. JUJUBE PT, CP

CONDIMENTS/SPICES ETC.

1. CORIANDER PT,CP2. CARDAMOM SC, RP3. CUMIN PT, CP4. FENNEL PT, CP5. TEA SI, CP6. COFFE SI, CP

FIBER CROPS

1. COTTON SC, CP

2. HEMP SC, CP

FORAGE CROPS

1. ALFALFA SC, CP

2. BERSEEM SI, CP

PULSES

• All are SELF- POLLINATED

* CROSS - POLLINATION

INCREASES SEED YIELD

STATUS

SI = > 50 %

PT/PG = > 15 %

US = 5 %

HS = FEW

Bees as Pollinators (Melittophily)

1. Dependence of bees on flowers for their brood food (nectar and pollen)

2. Morphological and Anatomical adaptations

BEES, THEIR FEEDING AND NESTING HABITS

1. Social Bees

• Honeybees• Stingless bees• Bumble bees

2. Solitary bees

S.No Name of Feeding Nesting bee Habits

Habits

1. True Honeybees

i) Apis mellifera Polylectic Cavity dweller

ii) A. cerana Polylectic Cavity dweller

iii) A. dorsata Polylectic Open iv) A. florea Polylectic Semi-dark

2 . Stingless Honeybees Polylectic Cavity dweller

3. Bumble bees Polylectic Deserted nests of voles/rats

S.No Name of Feeding Nesting bee

Habits Habits4. Other Non-Apis bees

i) Nomia melanderi Alfalfa/Oligolectic Alkaline soilii) Megachile rotundata Alfalfa/Oligolectic Leaf cutteriii) M. nana Alfalfa/Oligolectic Leaf

cutteriv) Chalicodoma rubripes Alfalfa/Oligolectic Wet mudv) C. lanata Pigeonpea/ Oligolectic Wet mud vi) M. bicolor Pigeonpea/ Oligolectic Leaf cuttervii) Eumegachile pugnata Sunflower/ Oligolectic Leaf cutterviii) C. mucorea Alfalfa/Oligolectic Leaf cutterix) Osmia lignaria propinqua Apple/ Oligolectic Woodx) O. cornuta Almond Oligolectic Woodxi) O. cornifrons Almond Oligolectic Woodxii) O. coerulescens Red clove/r Oligolectic Woodxiii) Xylocopa spp. Many/Polylectic

Wood/Hollow pithy stem

Honeybee pollination

Honey bees as Pollinators of crops

Honeybees as Indispensable pollinators of crops due to

1. Polylectic feeding habit

2. Floral constancy very high

3. Mobile colonies

Foraging Behaviour

An important component of pollination

Bees’ Complements Plants’

Advantage Advantage

Floral reward Plant reproductive harvest success

Foraging is influenced by

Blooming period

Bloom density

Bloom attractiveness

Blossom structure

Competing bloom presenting floral rewards

Weather factors

Foraging RangeGeneral Tendency of the Foragers

Forage at the nearest distance on a particular

plant species

Results in short foraging range of that species

Therefore Colonies are placed

Near or within the crop

General Foraging Range

A. Foraging on one crop when others present

50% of the honey bees tend to forage within 300 m from the hive if blooms are available

B. Foraging on one crop when no other crop present

General --- 3-5 km

Foraging distance great --- 7 km

Extreme distance --- 14 km

Foragers Distribution

1.Homogenous: If Plots are large with least land marks

1.Patchy: If plots are small/patchy resources

How to induce short foraging range ?

Depends upon the

Competition among apiaries

Distribution pattern of apiaries

Establishment of foraging Restricts foraging Territory distance of foragers of competing apiaries

Help

Colony strength and foraging Distance

i. No correlation found

ii. Only number of foragers increases with increase in colony strength

Isolation Distance400 m effective if

i. Cultivars are same

ii. Sown at the same time & identical agronomic practices

iii.Colonies placed simultaneously

iv.Colonies are of equal strength and number in the apiaries

v. If deviations from these, no isolation possible

vi.Only true for honeybees

CROP COMPETITION1. Medicago sativa vs Parkinsonia

aculeata

2. Eruca sativa vs Brassica campestris

3. Eruca sativa vs Brassica chinensis

4. Helianthus annuus vs Brassica campestris

5. Cajanus cajan vs Brassica campestris

6. Raphanus sativus vs Brassica rapa

7. Brassica oleracea vs Brassica rapa

8. Daucus carota vs Allium cepa

9. Brassica sp.. vs Eucalyptus

How to utilize Honeybees as Pollinators

Two ways

Placement of the Distribution of the colonies colonies

East facing Variable

Early risers Late risers

Utilization of Honeybees as Pollinators of crops

Three things

When to place the colonies?

At 5-10% flowering

Where to place the colonies?

Near the crop (within 100 m)

How to place the colonies?

Clumped or scattered

Pattern of Distribution of colonies

Crop area

Pattern of Distribution of colonies

Crop area

Kinds of colonies1. Grade A colonies- 10 frames

2. Grade B colonies- 8 frames

Unsealed brood- 2 frames

Sealed brood - 1 frame

Pollen - 1 frame

Honey - 1 frame

Characterization of the colonies

Grade - A field colonies

(i) Total comb area = 2700 sq inches

(ii)Total brood area = 1000 sq inches

(iii) Total adult bees = 28000

1 brood comb = 270 sq inches

Grade - A orchard colonies

(i) Total comb area = 1620 sq inches

(ii) Total brood area = 600 sq inches

(iii) Total adult bees = 22400

Grade B Colonies

Field colonies

i) Total comb area = 2025 sq inches

ii) Total brood area = 750 sq inches

iii)Total adult bees = 22500

Orchards colonies

i) Total comb area = 1215 sq inches

ii) Total broom area = 450 sq inches

iii)Total adult bees = 16800