Plant Introduction: Process and Types

Plant Introduction: Purpose and Procedure

• Plant Introduction: The process of introducing plants (a genotype or a group of genotypes) from their native environment to a new environment
• Primary Introduction: Introducing varieties that are immediately well-suited to the new environment, without genetic alteration. Examples: Dwarf wheat varieties like 'Sonora-64', 'Lerma rojo' and dwarf rice varieties like 'Taichung Native 1', 'IR-8'
• Secondary Introduction: Introducing varieties that require selection or hybridization with local varieties to improve traits. Examples: Wheat varieties 'Kalyan Sona' and 'Sonalika'
• Domestication: The process of bringing a wild species under cultivation by making them suitable for a new environment.
• Acclimatization: The adaptation process of a crop to a new climate and soil conditions.
  • Factors affecting acclimatization: Breeding system, Genetic variation, Crop duration
  • Factors influencing acclimatization success: 'Place effect' and selection of new genotypes.

Purpose of Plant Introduction

• Agricultural, Forestry, and Industrial Uses: Introduce new plants or crops for food, fiber, wood, medicinal purposes, and breeding materials for hybridization.
• Aesthetic Interest: Introduction of ornamental plants for beautification
• Germplasm Conservation: Maintaining older plant varieties threatened by the spread of high-yielding varieties.
• Studying Origin and Distribution: Understanding the origin and evolution of crop plants through their distribution and forms in different parts of the world.

Procedure of Plant Introduction

• Plant Procurement or Germplasm Acquisition:
  • Submit requests for the introduction of new crop plants or varieties to:
    • NBPGR (National Bureau of Plant Genetic Resources) - Within the country
    • IBPGR (International Bureau of Plant Genetic Resources) - Globally
  • Acquire materials through exchange programs, purchases, or gifts with/from friendly countries, individuals, or organizations.
• Packaging and Despatch:
  • Ensure the viability of propagule (seeds, tubers, runners, etc.) depending on the species.
  • Thoroughly clean propagules to remove contaminants, weed seeds, etc.
  • Treat with fungicides and pack carefully for safe delivery.
• Entry and Plant Quarantine:
  • Upon arrival, the material is inspected to prevent the entry and spreading of pests, diseases, and nematodes.
  • Treated with insecticides, fungicides, or nematicides before being released to the user.
• Cataloguing:
  • Introduced plants are given a unique number based on species, variety, and origin.
  • Plant materials are classified into three groups:
    • Exotic Collection -- prefix 'EC'
    • Indigenous Collection -- designated as 'TC'
    • Indigenous Wild Collection -- marked as 'TW'.
• Evaluation:
  • The performance of the introduction is assessed at various substations for:
    • Yield potential in different environments
    • Resistance to diseases and pests
• Multiplication and Distribution:
  • Promising introduced materials are propagated and released as new varieties after undergoing trials.

Agencies of Plant Introduction in India

• National Bureau of Plant Genetic Resources (NBPGR) - The central agency with headquarters in New Delhi and substations.
  • Functions: Gene bank for long-term storage, assessment of introduced materials, coordination of other agencies, and training in plant introduction, collection, and maintenance.
• Substations under NBPGR:
  • Shimla: Represents the temperate zone (2300m) for germplasm collection, acclimatization of temperate zone materials.
  • Jodhpur: Focused on exploring and acclimatizing plants for arid zones under CAZRI (Central Arid Zone Research Institute).
  • Amravati: Acclimatization and multiplication of introductions for the central zone of India.
  • KanyaKumari: Represents the tropical zone in South India.
  • Shillong: Collection of germplasm from North-East India.
• Other Agencies:
  • Forest Research Institute, Dehradun: Introduction, acclimatization, conservation, and testing of forest trees.
  • Botanical Survey of India: Introduction of medicinal and botanically important plants.
  • Central Research Institutes and Agricultural Universities: Play a role in collecting, introducing, and maintaining germplasm of crop plants.

Merits and Demerits of Plant Introduction

Merits:

• Provides entirely new crop plants to a region.
• Superior varieties may be originated directly or through selection or hybridization.
• Germplasm collection, maintenance, and protection of genetic variability are possible.
• The quickest and most economical method of crop improvement when introduced materials can be used directly.
• Introduction of some varieties to new areas might protect them from diseases.

Demerits:

• Introduction of weeds, diseases, and pests:
  • Weed examples: Argemone, Eichhornia, Lantana
  • Fungal diseases: Late blight of potato, flat smut of wheat, coffee rust, bunchy top of banana
  • Insect pests: Potato tuber moth, woolly aphis of apple, fluted scale of Citrus

Achievements of Plant Introduction

• Introduction of new crop species to the world:
  • Potato, maize, groundnut, chillies, coffee, rubber, guava, grape, pineapple, and ornamentals like Gulmohor, Phlox, Salvia, Aster
• Development of new crop varieties:
  • Direct Multiplication: Dwarf wheat varieties like 'Sonora 64', 'Lerma Rojo' and dwarf rice varieties like 'TN-1', 'IR-8'
  • Selection of Desirable Varieties: 'Kafyan Sona', 'Sonalika' from Mexican wheat varieties
  • Donor in Hybridization Programmes: Introduced varieties with superior traits used for disease resistance, pest resistance, stress resistance, plant type, and quality.
    • Examples: Dwarfing gene from TN-1 or IR-8 in rice, noble cane variety Saccharum officinarum for sugarcane
  • Mutation Breeding: Modification of introduced material (agronomically superior but lacking certain traits) with mutagens to rectify defects.