Unit 3 - Papaya, Jackfruit, Custard Apple, Aonla, Avocado, and Ber | Breeding of Fruit Crops

HORMA - 302

Breeding of Fruit Crops
Unit III: Breeding of Papaya, Jackfruit, Custard Apple, Aonla, Avocado, and Ber

📚 Contents

1. 1. PAPAYA (Carica papaya)
2. 2. JACKFRUIT (Artocarpus heterophyllus)
3. 3. CUSTARD APPLE (Annona squamosa)
4. 4. AONLA / INDIAN GOOSEBERRY (Emblica officinalis)
5. 5. AVOCADO (Persea americana)
6. 6. BER (Ziziphus mauritiana)
7. Summary & Future Thrust

1. PAPAYA (Carica papaya)

1. Origin, Distribution & Taxonomical Status

• Family: Caricaceae.
• Origin: Tropical America (Southern Mexico and Costa Rica).
• Distribution: India is the largest producer.
• Taxonomy: The genus Carica previously had many species, but recent revision suggests Carica papaya is the only species in this genus. Related species (like mountain papaya) are now moved to genus Vasconcellea (e.g., V. cundinamarcensis).

2. Cytogenetics

• Chromosome Number: 2n = 18.
• Sex Determination: Controlled by a single gene locus with three alleles:
  M₁: Dominant factor for maleness.
  M₂: Dominant factor for hermaphroditism.
  m: Recessive factor for femaleness.
• Combinations: mm (Female), M₁m (Male), M₂m (Hermaphrodite).
• Lethality: Homozygous dominant combinations (M₁M₁, M₂M₂, M₁M₂) are lethal to the zygote.

3. Blossom Biology & Breeding Systems

• Sex Forms: Highly variable (Polygamous).
  Dioecious: Male and Female plants separate (e.g., Pusa Nanha, Pusa Giant).
  Gynodioecious: Female and Hermaphrodite plants (e.g., Pusa Delicious, Coorg Honey Dew).
• Pollination: Cross-pollinated (wind and insects).
• Flowering: Continuous flowering 6-8 months after planting.

4. Breeding Objectives

• Dwarfism: For high density (1.2 x 1.2 m) and easy harvesting.
• Gynodioecious Nature: Preferred because hermaphrodites are self-pollinating and productive (every plant bears fruit).
• Resistance:
  Biotic: Papaya Ring Spot Virus (PRSV) – The most limiting factor.
  Abiotic: Frost and waterlogging.
• Quality: High papain content, red pulp colour (lycopene), high TSS (>12° Brix).

5. Breeding Approaches

A. Introduction:

Solo varieties (Sunrise Solo) introduced from Hawaii (USA). Known for small size and high quality.

B. Inbreeding and Selection:

Since papaya is cross-pollinated, varieties are maintained by Sib-mating (crossing female of a line with male/hermaphrodite of the same line).
Pusa Nanha: Developed by selection from open-pollinated populations; distinct dwarf mutant.

C. Hybridization:

Heterosis is exploited for yield. Crossing: Bagging flower buds before anthesis.
CO-3: Hybrid of CO-2 (Female) x Sunrise Solo (Hermaphrodite).
CO-7: Pusa Delicious x CO-3.

D. Mutation Breeding:

Pusa Nanha (Dwarf mutant) created through gamma irradiation (15 kR).

E. Resistance Breeding (Biotech):

Intergeneric crosses with Vasconcellea species (resistant to PRSV) often fail due to incompatibility (embryo abortion).
Embryo Rescue: Used to save hybrids of C. papaya x V. cauliflora.
Transgenics: SunUp and Rainbow (Hawaii) are GMO papayas resistant to PRSV (Coat protein mediated resistance).

6. Achievements

Institute	Variety	Sex Form	Key Features
IARI (New Delhi)	Pusa Nanha	Dioecious	Ultra-dwarf (106 cm), suitable for pot culture/high density.
	Pusa Delicious	Gynodioecious	High yield, excellent flavour (10-13° Brix).
	Pusa Majesty	Gynodioecious	High papain yield.
TNAU (Coimbatore)	CO-2	Dioecious	High papain extraction.
	CO-5	Dioecious	High papain (14-15g dry latex/fruit).
IIHR (Bengaluru)	Arka Surya	Gynodioecious	Sunrise Solo x Pink Flesh Sweet. Red pulp.
	Arka Prabhat	Gynodioecious	Advanced generation hybrid.

2. JACKFRUIT (Artocarpus heterophyllus)

1. Origin & Taxonomy

• Family: Moraceae.
• Origin: Western Ghats of India.
• Status: Largest tree-borne fruit in the world. Often commonly grouped into "Firm Flesh" (Kappa) and "Soft Flesh" (Rasadar) types.

2. Cytogenetics

• Chromosome Number: 2n = 4x = 56 (Tetraploid).

3. Blossom Biology

• Inflorescence: Cauliflorous (flowers on trunk/older branches).
• Sex: Monoecious. Male and female spikes (catkins) are separate but on the same tree. Male spikes: Smaller, appear first. Female spikes: Larger, thick peduncle.
• Pollination: Cross-pollination (Wind and Insects).
• Fruit: Syncarp (Multiple fruit).

4. Breeding Objectives

• Plant Type: Dwarf/compact canopy (standard trees are too huge).
• Fruit Quality: Low latex (Gum-less). High harvest index (more edible bulb ratio). Small to medium fruit size (2-5 kg) for nuclear families. Coppery red flakes (attractive).

5. Breeding Approaches

• Selection: The primary method. Surveying germplasm in Western Ghats/Assam.
• Clonal Selection: Identifying superior trees and propagating them vegetatively (grafting) rather than seeds.

6. Achievements

• PLR-1 (TNAU): Selection from Panruti local. High yield, off-season bearing.
• Konkan Prolific: Selection by KKV, Dapoli.
• Gumless Jack: Developed at IIHR (Selections).
• Sindoor: Red-fleshed variety.

3. CUSTARD APPLE (Annona squamosa)

1. Origin & Taxonomy

• Family: Annonaceae.
• Origin: Tropical America.
• Related Species:
  A. squamosa: Sugar apple / Sitaphal (Most common).
  A. reticulata: Ramphal (Bullock's heart).
  A. cherimola: Cherimoya (Best quality, cool climate).
  A. muricata: Soursop.
  A. atemoya: Atemoya (Hybrid).

2. Cytogenetics

• Chromosome Number: 2n = 14 (Diploid).

3. Blossom Biology

• Protogynous Dichogamy: Stigma becomes receptive before anthers dehisce.
• Female Phase: Flower opens, stigma receptive (usually evening/morning).
• Male Phase: Anthers release pollen 24 hours later.
• Pollination: Entomophilous (Beetles - Nitidulid beetles). Wind pollination is negligible. Poor fruit set is a major issue due to lack of pollinators.

4. Breeding Objectives

• Reduction of Seeds: High seed count is a consumer negative.
• Fruit Set: Improved self-fruitfulness.
• Shelf Life: Fruits are highly perishable (climacteric).
• Resistance: Mealybug.

5. Breeding Approaches

• Hybridization:
  Atemoya: Cross between A. squamosa (Sitaphal) x A. cherimola (Cherimoya). Combines heat tolerance of Sitaphal with quality of Cherimoya.
• Selection:
  Balanagar: Leading cultivar in Andhra Pradesh (Selection).
  Mammoth: Large fruit size.

6. Achievements

• Arka Sahan (IIHR): An interspecific hybrid: Island Gem (A. atemoya) x Mammoth (A. squamosa).
  Traits: Large fruits, very few seeds, slow ripening (better shelf life), very sweet (>30° Brix).
• APK-1: Selection from TNAU.

4. AONLA / INDIAN GOOSEBERRY (Emblica officinalis)

1. Origin & Taxonomy

• Family: Euphorbiaceae.
• Origin: India, Sri Lanka, Malaysia.
• Synonym: Phyllanthus emblica.

2. Cytogenetics

• Chromosome Number: 2n = 28.

3. Blossom Biology

• Inflorescence: Racemes on determinate branchlets.
• Sex: Monoecious. Male and female flowers on the same branchlet.
• Dormancy: Shows Zygotic Dormancy. Fertilization happens in spring (March), but the embryo sleeps; fruit development starts only after monsoon (July/August).
• Pollination: Wind and Honey bees.
• Self-Incompatibility: Many varieties (like Chakaiya) are self-incompatible and need pollinizers (like NA-7 or Krishna).

4. Breeding Objectives

• Banarasi: Used as a base for quality (large size) but is a shy bearer.
• Objectives: Remove alternate bearing, reduce fruit necrosis (boron deficiency), increase Vitamin C.

5. Breeding Approaches

• Selection: The most successful method. Historically, selections from Banaras district (UP).
• Chance Seedlings: Provide vast variation.

6. Achievements (Selections from Narendra Dev Univ, Faizabad)

• NA-7 (Neelum): Selection from seedling of Francis. Regular bearer, precocious, best for commercial cultivation.
• NA-6: Selection from Chakaiya.
• Krishna (NA-4): High yielding.
• Kanchan (NA-5): Regular bearer.
• Chakaiya: Alternate bearer, but hardy.

5. AVOCADO (Persea americana)

1. Origin & Taxonomy

• Family: Lauraceae.
• Origin: Southern Mexico.
• Races:
  Mexican: Small fruits, thin skin, high oil, cold hardy.
  Guatemalan: Large fruits, thick woody skin.
  West Indian: Large fruits, leathery skin, low oil, salt tolerant.

2. Cytogenetics

• Chromosome Number: 2n = 24.

3. Blossom Biology

• Unique Trait: Protogynous Diurnally Synchronous Dichogamy. Trees are classified into two flowering types based on when female/male parts function:
• Type A (e.g., Hass): Female in Morning (Day 1) → Male in Afternoon (Day 2).
• Type B (e.g., Fuerte): Female in Afternoon (Day 1) → Male in Morning (Day 2).
• Breeding Implication: For best fruit set, interplant Type A and Type B varieties to ensure pollen overlap.

4. Breeding Objectives

• Rootstocks: Resistance to Phytophthora Root Rot (Major killer).
• Quality: High oil content, nutty flavor, small seed.
• Yield: Regular bearing.

5. Achievements

• Fuerte: A natural Mexican x Guatemalan hybrid. Survives cold.
• Hass: The world's most popular variety (Black skin when ripe).
• TKD-1 (TNAU): Selection from long fruit trees.

6. BER (Ziziphus mauritiana)

1. Origin & Taxonomy

• Family: Rhamnaceae.
• Origin: Indo-China region.
• Species:
  Z. mauritiana: Indian Ber (Commercial).
  Z. jujuba (Z. vulgaris): Chinese Ber (Cold temperate).
  Z. nummularia: Jharber (Wild, used as rootstock).

2. Cytogenetics

• Chromosome Number:
  Most commercial Indian varieties are Tetraploids (2n=4x=48).
  Wild types are Diploids (2n=24).
  This ploidy difference makes hybridization difficult (triploid block).

3. Blossom Biology

• Inflorescence: Cymes in leaf axils.
• Flowering Time: Long duration (Sept-Nov).
• Pollination: Cross-pollination by insects (Housefly and Honeybees).
• Protandry: In some varieties, anthers mature first.

4. Breeding Objectives

• Early Maturity: To escape fruit fly infestation and hot summers.
• Resistance: Powdery Mildew and Fruit Fly.
• Quality: Large size, thin skin, crispy texture, small stone.

5. Breeding Approaches

• Selection: Local varieties were collected and standardized.
  Umran: Selected from Alwar (Rajasthan). Late maturing, large fruit (Golden yellow).
  Gola: Early maturing, round fruit.
• Rootstock Breeding: Using Z. nummularia for drought tolerance and dwarfing.
• Hybridization: Difficult due to minute flowers and high incompatibility.
  Early varieties: Seb, Gola.
  Late varieties: Umran.

6. Achievements

• Early Varieties: Gola, Seb.
• Mid Season: Mundia, Kaithli.
• Late Season: Umran (The "King of Ber").
• Hybrids (HAU, Hisar): Hisarale (Gola x Banarasi Karaka).

Summary & Future Thrust

Summary of Important Varieties (Quick Revision)

Crop	Key Varieties	Important Feature
Papaya	Pusa Nanha	Dwarf mutant.
	Arka Surya	Red flesh, Gynodioecious.
Jackfruit	PLR-1, Gumless Jack	High yield, quality.
Custard Apple	Arka Sahan	Hybrid, fewer seeds.
Aonla	NA-7, Krishna	Vitamin C rich, commercial.
Avocado	Hass (Type A), Fuerte (Type B)	Flowering synchrony essential.
Ber	Umran, Gola	Polyploid origins.

Future Thrust in Fruit Breeding

• Climate Resilience: Developing varieties tolerant to heat waves (mango, papaya) and salinity (citrus, ber).
• Rootstock Breeding: Moving beyond scion breeding to dedicated rootstocks for dwarfing and disease resistance.
• Marker Assisted Selection (MAS): For early identification of sex (in Papaya) and nucellar seedlings (in Citrus/Mango).
• Export Quality: Focus on shelf-life, colour, and seedlessness (Grape, Custard apple).
• Bio-fortification: Increasing lycopene in papaya/guava and Vitamin C in Aonla.

📚 References

Bose, T.K., Mitra, S.K. & Sanyol, D. (2002). Fruits of India – Tropical and Sub-tropical. Naya Udyog.

Chadha, K.L. (2001). Handbook of Horticulture. ICAR, New Delhi.

Janick, J. & Moore, J.N. (1996). Fruit Breeding. John Wiley & Sons.

Nijjar, G.S. (1977). Fruit Breeding in India. Oxford & IBH.

Pareek, O.P. (2001). Ber. ICAR.

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