Unit 2: Classification & Vegetative Propagation

Syllabus Reference: Introduction to annuals, biennials, perennials, herbs, shrubs, trees, climbers, succulents, cacti, palms, orchids, bulbous ornamentals. Cuttings: root, leaf, stem; Layering: simple, serpentine, mound, trench, air; [cite_start]Grafting and Budding [cite: 608-611].

1. Classification of Crops

• Based on Lifespan:
  • Annuals: Complete life cycle in one season (e.g., Marigold, Tomato).
  • Biennials: Vegetative growth in Year 1, Flowering/Seeding in Year 2 (e.g., Cabbage, Onion).
  • Perennials: Live for more than 2 years (e.g., Mango, Rose).
• Based on Growth Habit:
  • Herbs: Soft stem (Spinach).
  • Shrubs: Woody, bushy, no single trunk (Hibiscus).
  • Trees: Woody, single trunk (Jackfruit).
  • Climbers: Need support (Bougainvillea).
• Special Groups:
  • Succulents/Cacti: Fleshy parts to store water (Aloe vera, Opuntia).
  • Bulbous: Underground modified stems (Tulip, Gladiolus).

2. Propagation by Cuttings

A part of the plant is severed from the parent and induced to form roots.

• Stem Cuttings: Hardwood (Rose), Semi-hardwood (Croton), Softwood (Coleus).
• Leaf Cuttings: Leaf blade or petiole used (e.g., Bryophyllum, Begonia, Snake plant).
• Root Cuttings: Root pieces buried in soil (e.g., Guava, Breadfruit).

3. Layering Techniques

Rooting is induced on a stem while it is still attached to the parent plant.

• Simple Layering: Bending a lower branch into the soil and pinning it down (e.g., Jasmine).
• Air Layering (Gootee): Removing a ring of bark from an aerial shoot, covering it with moist moss and plastic. Roots form at the ring (e.g., Litchi, Lemon).
• Mound Layering (Stooling): Cutting the plant back to ground level and covering new shoots with soil (e.g., Guava).

4. Grafting and Budding

Joining two plant parts to grow as one.

• Components:
  Scion: Upper part (Desired variety).
  Stock (Rootstock): Lower part (Provides root system, disease resistance).
• Grafting Methods: Cleft grafting, Whip grafting, Approach grafting (Inarching).
• Budding (T-Budding / Shield Budding): A single bud with a shield of bark is inserted into a T-shaped cut on the stock (e.g., Rose, Citrus).