HORMA - 302
Breeding of Fruit Crops
Breeding of Fruit Crops
Unit V: Breeding of Temperate Fruit Crops
📚 Contents
1. APPLE (Malus domestica)
1. Origin, Distribution & Taxonomical Status
- Family: Rosaceae (Rose family).
- Subfamily: Pomoideae (Pome fruits).
- Origin: Central Asia (Almaty, Kazakhstan).
- Taxonomy:
Malus domestica: The modern cultivated apple.
Malus sylvestris: Crab apple (Wild ancestor).
Malus baccata: Siberian crab apple (Used for rootstocks).
2. Cytogenetics
- Chromosome Number: Basic number x = 17.
- Diploid (2n=34): Most commercial varieties (e.g., Royal Delicious, Golden Delicious). Fertile, good pollen.
- Triploid (3n=51): Larger trees, larger leaves, but pollen sterile (cannot pollinate others).
Example of Triploids: Baldwin, Mutsu. - Exam Note: Triploid varieties always need two other pollinizer varieties in the orchard to ensure fruit set.
3. Blossom Biology & Breeding Systems
- Inflorescence: Cyme (Central flower opens first, called the "King Bloom").
- Pollination: Entomophilous (Honey bees are essential).
- Self-Incompatibility: Most apples are Self-Incompatible (cannot fertilize themselves).
- Mechanism: Gametophytic Self-Incompatibility (GSI) controlled by S-alleles.
- Therefore, commercial orchards must plant "Pollinizer" varieties (e.g., Golden Delicious) interspersed with the main variety (e.g., Red Delicious).
4. Breeding Objectives & Ideotypes
- Spur Type Habit: Trees that bear fruit on short shoots (spurs) rather than long branches. Allows high-density planting (HD).
- Colour: Full red development even in lower altitudes/warmer climates.
- Resistance:
Biotic: Apple Scab (Venturia inaequalis) - the most devastating disease; Woolly Aphid.
Abiotic: Low Chilling requirement (to grow apple in warmer areas). - Ideotype: Spur bearing, compact tree, disease resistant, red skinned fruit, long shelf life.
5. Breeding Approaches
- A. Introduction: The backbone of the Indian apple industry is introduced varieties: Red Delicious, Royal Delicious, Golden Delicious (from USA).
- B. Selection (Bud Sports): Apples mutate frequently. Selection of these natural mutations (Bud sports) is a major method. Vance Delicious and Top Red are bud sports of Red Delicious (selected for better color).
- C. Hybridization:
Scab Resistance: Crossing commercial varieties with wild species (M. floribunda) carrying the Vf gene (gene for scab resistance).
Prima, Priscilla, Sir Prize are famous scab-resistant hybrids from the USA. - D. Rootstock Breeding:
Breeding for size control (Dwarfing) and Woolly Aphid resistance.
Malling Series (UK):
M9: Dwarfing (Small tree).
M27: Ultra dwarf.
MM106: Semi-dwarf, resistant to Woolly Aphid.
6. Achievements
| Institute/State | Variety | Parentage/Type | Key Features |
|---|---|---|---|
| CITH (Srinagar) / Mashobra | Lal Ambri | Red Delicious x Ambri | Combines color of Delicious with keeping quality of Ambri. |
| Sunehari | Ambri x Golden Delicious | Yellow skin, sweet. | |
| Chaubattia Princess | Early Shanburry x Red Delicious | Early maturing. | |
| Himachal | Ambri | (Selection) | Native to Kashmir, excellent shelf life but alternate bearer. |
2. PEAR (Pyrus spp.)
1. Origin & Taxonomy
- Family: Rosaceae.
- Two Major Groups:
European Pear (Pyrus communis): Soft, melting flesh (Butter pear). Shape is pyriform (neck). Origin: Europe/West Asia. E.g., Bartlett.
Asian Pear (Pyrus pyrifolia): Crunchy, crisp like apple (Sand pear). Shape is round. Origin: China. E.g., Patharnakh.
2. Cytogenetics
- Chromosome Number: 2n = 34.
- Polyploidy exists but diploids are preferred for fertility.
3. Blossom Biology
- Inflorescence: Corymb.
- Pollination: Cross-pollinated (Bees).
- Self-Incompatibility: Gametophytic type (like apple). Need pollinizers.
- Fruit: Pome. Distinct feature is Grit Cells/Stone Cells (Sclereids) which give the gritty texture.
4. Breeding Objectives
- Texture: Reducing grit cells (stone cells) for smoother flesh.
- Resistance: Fire Blight (Erwinia amylovora) - a bacterial disease that kills trees.
- Low Chilling: To grow pears in sub-tropical plains (like Punjab/UP).
5. Breeding Approaches
- Interspecific Hybridization: Crossing European x Asian pears to get "Soft but Hardy" fruits. Keiffer and LeConte are natural hybrids of P. communis x P. pyrifolia.
- Mutation: Red skinned pears (e.g., Max Red Bartlett).
6. Achievements
- Patharnakh: The hardiest variety for North Indian plains.
- Punjab Beauty: Semi-soft pear, tolerates heat.
- Bartlett: The standard world variety (also called Williams).
3. PEACH (Prunus persica)
1. Origin & Taxonomy
- Family: Rosaceae. Subfamily: Prunoideae (Stone fruits).
- Origin: China.
- Taxonomy:
Prunus persica: Peach (Fuzzy skin).
Prunus persica var. nucipersica: Nectarine (Smooth/Fuzzless skin). Nectarine is genetically identical to peach except for one recessive gene (g) that removes the fuzz.
2. Cytogenetics
- Chromosome Number: 2n = 16 (Diploid).
3. Blossom Biology
- Flower: Solitary (single flower), pink, beautiful.
- Breeding System: Self-Pollinated (Autogamy). This is unique among temperate fruits (most are cross-pollinated).
- Implication: You can plant a solid block of one peach variety; no pollinizer is needed.
- Fruit: Drupe (Stone fruit).
4. Breeding Objectives
- Low Chilling: Developing varieties that flower in subtropical climates (Delhi, Punjab) with only 200-300 chilling hours (standard peaches need 800+ hours).
- Fruit Quality: Yellow flesh (Vitamin A), Free-stone (stone separates easily from flesh).
- Resistance: Peach Leaf Curl (Fungal disease).
5. Breeding Approaches
- Hybridization: Emasculation is needed. Crossing low chill x high quality types.
- Introduction: Florida series (USA) revolutionized peach growing in warm climates.
6. Achievements
- Prabhat: Early maturing.
- Shan-e-Punjab: Excellent low-chill variety for plains.
- Sharbati: Improvement over local stock.
- Florida Prince: Introduced low-chill variety.
4. PLUM (Prunus spp.)
1. Origin & Taxonomy
- Family: Rosaceae.
- Two Major Groups:
European Plum (Prunus domestica): Blue/Purple skin, high sugar, used for drying (Prunes).
Japanese Plum (Prunus salicina): Red/Yellow skin, juicy, used for fresh eating. (Grown in India).
2. Cytogenetics
- European Plum: Hexaploid (2n=6x=48).
- Japanese Plum: Diploid (2n=2x=16).
- Note: You cannot easily cross European and Japanese plums due to this ploidy barrier.
3. Blossom Biology
- Flowering: White flowers, appear before leaves.
- Self-Incompatibility: Very common in Japanese plums. Requires pollinizers.
- Santa Rosa is a self-compatible variety (rare exception).
4. Breeding Objectives
- Low Chilling: For Indian plains.
- Quality: High sugar, less acidity near the pit (stone).
- Resistance: Bacterial canker.
5. Achievements
- Santa Rosa: The most popular hill variety (Self-fertile, red flesh).
- Satluj Purple: For plains (Punjab/Haryana).
- Kala Amritsari: Drought tolerant, for processing.
5. APRICOT (Prunus armeniaca)
1. Origin & Taxonomy
- Family: Rosaceae.
- Origin: China / Central Asia.
- Cultivars: Commonly called "Khubani" or "Jardalu".
2. Cytogenetics
- Chromosome Number: 2n = 16.
3. Blossom Biology
- Flowering: Flowers very early in spring.
- The Problem: Because they flower so early, the blossoms are often killed by late spring frosts.
- Pollination: Most are self-incompatible, but some (like Royal) are self-fertile.
4. Breeding Objectives
- Late Flowering: To escape spring frosts.
- Kernel Quality: Breeding "Sweet Kernel" varieties (some apricot kernels are bitter and toxic due to HCN/cyanide). Sweet kernels can be eaten like almonds.
- Drying Quality: High TSS (>20° Brix) for drying.
5. Achievements
- Chaubattia Alankar: Selection from diverse germplasm.
- New Castle: Early maturing.
- Halman: Famous Ladakhi variety, excellent for drying.
- Nari: Sweet kernel variety.
Summary of Important Concepts for Exam (Unit V)
- Chilling Requirement: The number of cold hours (<7 a="" and="" br="" break="" dormancy="" flower="" in="" needs="" spring.="" to="" tree="" winter="">High Chill: Apple, Cherry (Kashmir/Himachal).
Low Chill: Peach, Low-chill Pears (Punjab/Plains). - Rootstocks:
M9: Dwarfing rootstock for Apple.
Colt: Rootstock for Cherry.
Wild Apricot (Chulli): Rootstock for Apricot/Peach. - Spur Types: Apple trees with short internodes, ideal for High Density Planting (HDP).
- Stone Fruits: Peach, Plum, Apricot, Cherry (Fruit type is Drupe; seed is hard stone).
- Pome Fruits: Apple, Pear (Fruit type is Pome; seeds in cartilaginous core).
📚 References
Bose T.K., Mitra S.K. & Sanyol D. (2002). Temperate Fruits. Naya Udyog.
Janick J. & Moore J.N. (1996). Fruit Breeding. Vols I-III. John Wiley & Sons.
Chadha K.L. (2001). Handbook of Horticulture. ICAR.
Westwood M.N. (1993). Temperate-Zone Pomology. Timber Press.
Nijjar G.S. (1977). Fruit Breeding in India. Oxford & IBH.