pollination of crops slides
TRANSCRIPT
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