Plant Introduction – History, Purpose, Procedure, Merits, Demerits

What is Plant Introduction?

• Plant introduction refers to the process of bringing a genotype or a collection of genotypes into a new environment where they were previously untested or not grown. This process can encompass the introduction of new varieties of crops already established in the region, the inclusion of wild relatives of the crop species, or the introduction of entirely novel crop species. Such introductions often involve moving plant materials from different countries or continents, though they can also occur within the same country.
• For instance, within-country introductions include the expansion of grape cultivation in Maharashtra, the introduction of wheat cultivation in West Bengal, and the establishment of rice cultivation in Punjab. These instances demonstrate the broader application of plant introduction beyond international contexts, highlighting its role in regional agricultural development and crop diversification.
• Therefore, plant introduction serves as a crucial mechanism for enhancing agricultural practices, increasing crop varieties, and potentially improving food security by adapting crops to new or varied environments.

Types of Plant Introduction

Plant introduction, a crucial aspect of crop improvement and agricultural development, can be categorized into two main types: primary introduction and secondary introduction. Each type serves distinct purposes and involves different processes to enhance crop varieties.

1. Primary Introduction

• Definition: Primary introduction refers to the process of introducing a plant variety into a new environment without altering its original genetic makeup. This type of introduction occurs when the plant variety is well-suited to the new environment, and thus, no genetic modification or selection is necessary before its commercial cultivation.
• Characteristics:
  • Unmodified Genotype: The plant variety retains its original genetic characteristics.
  • Suitability: The introduced variety is expected to perform well in the new environment based on its inherent traits.
  • Prevalence: This type of introduction is less common, particularly in regions with established crop improvement programs.
• Examples:
  • Semidwarf Wheat Varieties: Varieties such as Sonora 64 and Native 1, 018, and IR25 are instances of primary introduction. These varieties were introduced into new environments without prior genetic modification.

2. Secondary Introduction

• Definition: Secondary introduction involves additional processes beyond the initial introduction. This type may include selection to isolate superior traits or hybridization with local varieties to transfer specific characteristics.
• Characteristics:
  • Selection: The introduced variety may be subjected to selection processes to identify and isolate superior traits.
  • Hybridization: The variety may be hybridized with local varieties to integrate desirable traits from the introduced variety into the local gene pool.
  • Prevalence: Secondary introduction is more common than primary introduction due to its focus on optimizing and adapting varieties to local conditions.
• Processes:
  • Selection:
    • Objective: To identify superior varieties or traits within the introduced material.
    • Outcome: Development of enhanced varieties that exhibit improved performance or adaptation.
  • Hybridization:
    • Objective: To cross the introduced variety with local varieties, aiming to transfer beneficial traits.
    • Outcome: Creation of new varieties that combine desirable traits from both the introduced and local varieties.
• Examples:
  • Kalyan Sona and Sonalika Wheat: These varieties were developed through secondary introduction by selecting from materials introduced from CIMMYT, Mexico.
  • Semidwarf Wheat and Rice Varieties: These were developed through hybridization, incorporating traits from introduced varieties into local cultivars.

History of Plant Introduction

The movement of crop plants across regions has been a significant factor in agricultural development, largely paralleling human migration and trade routes. This transfer of plant species from their centers of origin to new environments has shaped the agricultural landscape globally.

Early Plant Introductions

• Ancient Movements: The dispersal of plants such as mung beans, mustard (Brassica juncea), pears, apples, and walnuts (Juglans regia) from Central Asia into various regions of India illustrates early agricultural exchanges. Similarly, plants like sesame, jowar (Sorghum bicolor), pigeon peas (Cajanus cajan), Asian cotton (Gossypium herbaceum), and finger millet (Eleusine coracana) moved from Africa to India during prehistoric times.
• Significance: These early introductions contributed significantly to the agricultural diversity seen in various regions, highlighting the role of human migration and trade in expanding plant species’ geographical ranges.

Medieval to Early Modern Plant Introductions

• Islamic Influence (1300 A.D.): During the medieval period, Muslim invaders introduced cherries and grapes from Afghanistan into India, demonstrating the role of military and cultural exchanges in plant transfer.
• Portuguese Contributions (15th-16th Century): In the 15th and 16th centuries, Portuguese explorers and traders brought a variety of crops to new regions, including maize, peanuts, chillies, potatoes, sweet potatoes, guavas, pineapples, papayas, cashew nuts (Anacardium occidentale), and tobacco. These introductions had profound impacts on local agriculture and cuisine.
• East India Company (Late 18th Century): The East India Company facilitated the introduction of tea (Camellia sinensis), lychees, and loquats from China; cabbage, cauliflower, and other vegetables from the Mediterranean; annatto (Bixa arellana) from the West Indies; and mahogany timber trees. This period marked a significant increase in the diversity of plants introduced to India and other regions.

19th Century Developments

• Botanic Gardens: The establishment of botanic gardens played a pivotal role in plant introduction. For instance, the Calcutta Botanic Gardens, founded in 1781, became a center for the cultivation and study of introduced species. The Kew Botanic Gardens in England was instrumental in introducing quinine and rubber trees from South America to India.
• Research Stations: In the latter part of the 19th century, agricultural and horticultural research stations emerged across India. These institutions introduced various horticultural and agricultural plants. However, the lack of coordination among these stations led to fragmented efforts in plant introduction, affecting the overall efficiency and integration of new species into local agriculture.

Plant Introduction Agencies in India

In India, the process of plant introduction—bringing new plant species into cultivation and study—is managed by a range of specialized agencies. These organizations oversee the acquisition, testing, and maintenance of plant germplasm, which is crucial for enhancing agricultural and horticultural diversity.

National Bureau of Plant Genetic Resources (NBPGR)

1. Establishment and Evolution:
   • 1945: The Indian Agricultural Research Institute (IARI) in New Delhi initiated a centralized plant introduction agency as part of its Division of Botany. This initiative was initially funded by the Indian Council of Agricultural Research (ICAR).
   • 1956: The scheme was expanded under the second five-year plan to become the Plant Introduction and Exploration Organisation.
   • 1976: It was restructured into the National Bureau of Plant Genetic Resources (NBPGR). Despite changes in its structure, the core functions related to the introduction and maintenance of agricultural and horticultural germplasm have remained consistent. However, the scope and scale of activities have considerably broadened.
2. Functions:
   • Introduction and Maintenance: NBPGR is responsible for the introduction, maintenance, and conservation of germplasm for a wide range of agricultural and horticultural plants.
   • Coordination: The bureau coordinates plant introduction activities across India, ensuring that all introductions are routed through its system.
3. Substations:
   • Simla (Himachal Pradesh): Located at approximately 2,300 meters above sea level, this substation represents the temperate climatic zone.
   • Jodhpur (Rajasthan): This substation caters to the arid climatic zone.
   • Kanya Kumari (Tamil Nadu): Represents the tropical zone.
   • Akola (Maharashtra): Covers the mixed climatic zone. The substation was recently moved from Amravati.
   • Shillong (Meghalaya): A new substation aimed at collecting germplasm from Northeast India, which is known for its genetic variability in crops such as rice, citrus, and maize.

Other Plant Introduction Agencies

1. Forest Research Institute (Dehradun):
   • Focus: Specializes in the introduction, maintenance, and testing of germplasm related to forest trees.
2. Botanical Survey of India:
   • Establishment: Founded in 1890.
   • Role: Responsible for the introduction, testing, and maintenance of plant species with medicinal and botanical significance.
3. Central Research Institutes:
   • Examples: Institutes dedicated to crops such as tea, coffee, sugarcane, potato, tobacco, and rice.
   • Function: These institutes introduce, test, and maintain plant materials pertinent to their respective crops.
4. Individual Scientists and Universities:
   • Introduction Activities: Although individuals and universities may introduce plant materials, all such activities are coordinated and regulated by the NBPGR.

Activities of the National Bureau of Plant Genetic Resources (NBPGR)

The National Bureau of Plant Genetic Resources (NBPGR) undertakes a variety of critical activities aimed at managing and enhancing plant genetic resources. These activities ensure the conservation, introduction, and effective utilization of plant germplasm. Below is a detailed summary of the bureau’s key functions:

1. Germplasm Introduction:
   • Activity: The bureau introduces essential germplasm from international counterparts or other agencies located in different countries.
   • Purpose: This activity ensures the availability of diverse genetic materials necessary for research and crop improvement.
2. Exploration and Collection:
   • Activity: The bureau organizes exploratory missions both within India and abroad to collect valuable germplasm.
   • Purpose: These explorations aim to gather diverse plant genetic materials that are crucial for broadening the genetic base of crops and enhancing agricultural resilience.
3. Inspection and Quarantine:
   • Activity: The bureau is responsible for inspecting and quarantining all introduced plant materials.
   • Purpose: This function ensures that the germplasm is free from pests and diseases before it is distributed or utilized, thereby preventing potential agricultural and ecological issues.
4. Testing, Multiplication, and Maintenance:
   • Activity: The bureau tests, multiplies, and maintains germplasm obtained from various sources. This can be conducted at the bureau’s own substations or by other Central Institutes of the Indian Council of Agricultural Research (ICAR).
   • Purpose: These processes ensure the preservation and quality of germplasm, facilitating its use in research and crop improvement.
5. Supply of Germplasm:
   • Activity: The bureau supplies germplasm to scientists and institutions upon request. If required germplasm is not available domestically, it can be procured from external sources.
   • Purpose: This service supports research and development efforts by providing access to necessary genetic materials.
6. Record Maintenance:
   • Activity: The bureau maintains detailed records on plant names, variety names, propagating materials, special characteristics, sources, dates, and other pertinent information about the germplasm received.
   • Purpose: Comprehensive record-keeping ensures accurate tracking and management of plant genetic resources.
7. International Germplasm Supply:
   • Activity: The bureau supplies germplasm to its counterparts and other agencies in different countries.
   • Purpose: This exchange fosters international collaboration and supports global plant genetic resource management.
8. Publication of Exchange and Collection Lists:
   • Activity: The bureau publishes exchange and collection lists. The Food and Agriculture Organisation (FAO) has been publishing an Introduction Newsletter since 1957, and NBPGR also publishes its own lists and catalogues.
   • Purpose: These publications provide transparency and information regarding the movement and availability of plant genetic resources.
9. Natural Gene Sanctuaries:
   • Activity: The bureau sets up natural gene sanctuaries to protect genetic resources that are at risk.
   • Purpose: These sanctuaries help conserve endangered plant species and their genetic diversity.
10. Plant Improvement:
    • Activity: The bureau works on the improvement of specific plant types, including medicinal and aromatic plants.
    • Purpose: This activity aims to enhance the quality and utility of plants with significant economic and health benefits.

Purpose of Plant Introduction

Plant introduction serves a variety of strategic and practical purposes aimed at enhancing agricultural productivity, improving crop varieties, and supporting scientific research. The primary objectives of plant introduction can be categorized as follows:

1. To Obtain an Entirely New Crop Plant:
   • Objective: Introductions may lead to the establishment of new crop species that were previously unavailable in the region.
   • Examples: Important crops such as maize, potato, tomato, tobacco, and soybean were introduced from other regions and have become integral to agriculture.
2. To Serve as New Varieties:
   • Objective: Plant introductions can result in the development of superior commercial varieties that offer improved yield, quality, or resistance traits.
   • Examples: The Mexican semi-dwarf wheat varieties like Sonora 64 and Lerma Rojo, and semi-dwarf rice varieties such as TN 1 and IR 8, are notable examples that have been introduced and commercialized for their enhanced performance.
3. To be Used in Crop Improvement:
   • Objective: Introduced germplasm can be used in hybridization programs to enhance local varieties and develop new, improved cultivars.
   • Examples: The Pusa Ruby tomato was developed through a cross between Meeruty and Sioux, the latter being an introduction from the U.S.A.
4. To Save the Crop from Diseases and Pests:
   • Objective: Introducing crops into new areas can help mitigate the impact of diseases and pests that affect local varieties.
   • Examples: Coffee was introduced into South America from Africa to combat leaf rust, while rubber was brought to Malaya from South America to protect against a leaf disease.
5. For Scientific Studies:
   • Objective: Collections of introduced plants are utilized in scientific research to study biosystematics, evolution, and the origin of plant species.
   • Notable Contributions: N.I. Vavilov’s work on centers of origin and homologous series in variation was based on extensive plant collections, contributing significantly to our understanding of plant genetics and diversity.
6. Aesthetic Value:
   • Objective: Introduction of ornamental plants, shrubs, and lawn grasses fulfills aesthetic and decorative needs, enhancing the visual appeal of environments.
   • Function: These plants are valued for their contribution to landscaping and social settings, enriching human experiences with their beauty.

Procedure of Plant Introduction

The procedure for introducing new plant germplasm involves several critical steps to ensure that the materials are effectively integrated into local agriculture and research. These steps include procurement, quarantine, cataloguing, evaluation, acclimatization, multiplication, and distribution.

1. Procurement:
   • Process: Any individual or institution seeking to introduce new germplasm into India must route their request through the National Bureau of Plant Genetic Resources (NBPGR) in New Delhi.
   • Routes:
     1. Direct Request: The individual or institution directly contacts a foreign source to send the germplasm through the NBPGR.
     2. NBPGR Request: The individual or institution submits their germplasm requirements to the NBPGR, which then arranges for import.
2. Quarantine:
   • Purpose: Quarantine aims to prevent the spread of diseases, pests, and weeds by isolating introduced plant materials.
   • Procedures:
     • Inspection: All plant propagules are inspected for contamination.
     • Treatment: Contaminated materials undergo fumigation or other treatments to eliminate threats.
     • Isolation: If necessary, materials are grown in isolation to monitor for any remaining issues.
   • Rules: These processes are governed by quarantine regulations to ensure plant health and safety.
3. Cataloguing:
   • Entry and Classification: Upon receipt, each introduction is assigned an entry number. Detailed information, including species name, variety, origin, adaptation, and characteristics, is recorded.
   • Classification Groups:
     1. Exotic Collections (EC): Materials from foreign sources.
     2. Indigenous Collections (IC): Materials from within India.
     3. Indigenous Wild Collections (IW): Wild plant materials from India.
4. Evaluation:
   • Purpose: The performance of new introductions is assessed to determine their potential benefits.
   • Evaluation Sites: Introductions are evaluated at various NBPGR substations or, for certain crops, at Central Research Institutes such as those for rice, sugarcane, potato, and tobacco.
   • Criteria: Performance is evaluated under conditions conducive to heavy pest and disease attacks to assess resistance and adaptability.
5. Acclimatization:
   • Definition: Acclimatization is the process by which introduced varieties adapt to new environmental conditions.
   • Process: This involves natural selection, where genotypes better suited to the new environment become more prevalent.
   • Factors Influencing Acclimatization:
     1. Mode of Pollination: Cross-pollination typically leads to greater genetic variability and adaptability compared to self-pollination.
     2. Genetic Variability: A higher range of genetic variability in the original population enhances acclimatization.
     3. Lifecycle Duration: The length of the crop’s lifecycle affects the extent of acclimatization.
6. Multiplication and Distribution:
   • Process: Promising introductions are multiplied and developed into new varieties after thorough trials.
   • Maintenance: Most introductions are characterized for desirable traits and maintained for future use.
   • Supply: These materials are available for crossing programs and can be supplied by the bureau upon request.

Some Important Achievements of Plant Introduction

Plant introduction has significantly influenced agriculture and horticulture by facilitating the acquisition and development of new crop species and varieties. The achievements resulting from plant introduction encompass a wide range of applications, from new crop species to hybrid varieties. The following points outline some notable successes:

1. Introduction of New Crop Species:
   • Objective: Plant introductions have led to the establishment of various important crop species in new regions.
   • Examples:
     • Potato, maize, groundnut, chillies, coffee, Hevea rubber, guava, grape, pineapple, and papaya.
     • Ornamentals such as gulmohar, phlox, salvia, and aster.
     • Recent Introductions: Soybean and sugarbeet (1960); oil palm and jojoba are still under experimental evaluation.
2. Directly Released Varieties:
   • Objective: Some introductions are directly released as commercially viable crop varieties.
   • Examples:
     • Wheat: Semidwarf varieties such as Sonora 64 and Lerma Rojo.
     • Rice: Varieties including TN 1, IR 8, IR 21, and IR 28.
     • Other Crops: Ridley wheat, Kent oat, Virginia Gold tobacco, Bragg, Lee, Clark 63, and Hill Davis soybeans, and Sioux tomato.
     • Vegetables: Varieties of cowpea, cauliflower, onion, and lettuce.
3. Varieties Selected from Introductions:
   • Objective: Selection from introduced germplasm has led to the development of new crop varieties.
   • Examples:
     • Wheat: Kalyan Sona and Sonalika, selected from introductions from CIMMYT, Mexico.
     • Other Crops: Jamnagar Giant and Improved Ghana bajra; Pusa Lal and Pusa Sunehari sweet potato; Pusa Basmati rice; vegetable cowpea; Japanese White and 40 Days radish.
4. Varieties Developed through Hybridization:
   • Objective: Hybridization involving introduced germplasm has significantly contributed to the development of new crop varieties.
   • Examples:
     • Wheat: Many semidwarf wheat varieties derive from crosses with Mexican semidwarf wheats.
     • Rice: Semidwarf varieties often incorporate the dwarfing gene from Dee-geo-woo-gen, such as TN 1 or IR 8.
     • Maize and Jowar: Hybrid varieties frequently include introduced or derived germplasm.
     • Sugarcane: All varieties originate from introduced noble canes, specifically Saccharum officinarum.
     • Vegetables: Pusa Ruby tomato (cross between Meeruti and Sioux), Pusa Early Dwarf Tomato (cross between Meeruti and Red Cloud), Pusa Kesar carrot, Pusa Kanchan turnip, AF 3, and S 350 bajra.

Advantages/Merits of Plant Introduction

Plant introduction offers several significant benefits, enhancing agricultural diversity and productivity. The following points detail the key advantages:

1. Provision of New Crop Plants:
   • Objective: Introductions can introduce entirely new crop species into a region.
   • Benefit: This expands the range of crops available, potentially improving food security and agricultural resilience.
2. Development of Superior Varieties:
   • Objective: Introduced germplasm can lead to the creation of superior crop varieties through selection or hybridization.
   • Benefit: This process enhances crop yields, quality, and adaptability. For example, varieties such as the Mexican semidwarf wheat and TN 1 rice were directly released for cultivation due to their improved traits.
3. Germplasm Collection and Protection:
   • Objective: Introduction and exploration are essential methods for collecting diverse germplasm.
   • Benefit: These methods safeguard genetic variability and protect against genetic erosion. They are critical for maintaining a broad genetic base necessary for future crop improvement.
4. Efficient Crop Improvement:
   • Objective: Plant introduction can provide a rapid and cost-effective means of crop enhancement.
   • Benefit: When new plant materials are introduced and released as varieties—either directly or after simple selection—the process of crop improvement becomes quicker and more economical compared to other methods.
5. Protection from Diseases:
   • Objective: Introduction of plants into new, disease-free areas can protect crops from damage.
   • Benefit: For instance, coffee and rubber were introduced into regions where they are free from specific diseases that could otherwise reduce their yield and quality.

Disadvantages/Demerits of Plant Introduction

While plant introduction offers numerous benefits, it also presents several challenges, primarily related to the potential introduction of harmful organisms and ecological disturbances. The following points outline the key disadvantages:

1. Introduction of Weeds:
   • Objective: Some introduced plants can become invasive weeds in their new environment.
   • Examples:
     • Argemone mexicana: A noxious weed introduced into India, affecting crop yields.
     • Eichhornia crassipes: Also known as water hyacinth, it disrupts aquatic ecosystems.
     • Phalaris minor: Commonly known as “gehuns,” it competes with crops and reduces agricultural productivity.
   • Impact: These weeds can outcompete native plants, reduce biodiversity, and disrupt agricultural practices.
2. Introduction of Diseases:
   • Objective: Plant introductions can inadvertently bring diseases that affect local crops.
   • Examples:
     • Late Blight of Potato: Introduced from Europe in 1883, it severely impacts potato production.
     • Flag Smut of Wheat: Originated from Australia, causing significant wheat crop losses.
     • Coffee Rust: Brought from Ceylon in 1876, it affects coffee plants.
     • Bunchy Top of Banana: Introduced from Ceylon in 1940, leading to banana crop failures.
   • Impact: These diseases can spread rapidly, causing substantial economic damage and requiring extensive control measures.
3. Introduction of Insect Pests:
   • Objective: New pests can be introduced along with plant materials, impacting local agriculture.
   • Examples:
     • Potato Tuber Moth: Arrived from Italy in 1900, damaging potato crops.
     • Woolly Aphis of Apple: A pest affecting apple trees.
     • Fluted Scale of Citrus: Impacting citrus plants.
   • Impact: These pests can infest and damage crops, leading to increased pesticide use and economic losses.
4. Ecological Disruption:
   • Objective: Some introduced species can disturb the ecological balance of their new habitat.
   • Examples:
     • Water Hyacinth: Introduced as an ornamental plant, it has become an invasive species affecting water bodies.
     • Lantana camara: Initially introduced for ornamental purposes, it has spread widely and become a troublesome weed.
     • Eucalyptus sp.: Brought from Australia, it is known to deplete subsoil water reserves, potentially causing environmental damage.
   • Impact: Invasive species can alter habitats, reduce native biodiversity, and cause environmental imbalances.
5. Quarantine Failures:
   • Objective: Historically, the lack of effective quarantine measures has allowed harmful organisms to enter new regions.
   • Impact: Although modern quarantine laws are strict, any lapse or error can still permit the entry of detrimental species, leading to significant economic and ecological consequences.

Facts

1. Did you know that plant introduction can bring entirely new crop species to a region, enhancing agricultural diversity and productivity?
2. Have you heard that plant introduction can lead to the development of superior varieties, which are either released directly or improved through selection and hybridization?
3. Are you aware that the introduction of new plant varieties can be a rapid and cost-effective method of crop improvement, especially when these varieties are released directly or after minimal selection?
4. Can you believe that introducing plants into new, disease-free areas can protect crops from specific diseases and pests by preventing their spread?
5. Did you know that some introduced plant species have become invasive, disrupting local ecosystems and outcompeting native flora?
6. Have you heard that the introduction of certain weeds, such as Argemone mexicana and Eichhornia crassipes, can have significant negative impacts on agricultural and natural environments?
7. Are you aware that introduced diseases, like late blight of potatoes and coffee rust, have historically caused major crop losses in their new regions?
8. Can you believe that insect pests, such as the potato tuber moth and woolly aphis, have been introduced along with plant materials, leading to new agricultural challenges?
9. Did you know that some introduced plants can deplete natural resources, such as water, affecting the surrounding ecosystem? For example, Eucalyptus sp. has been known to deplete subsoil water reserves.
10. Have you heard that rigorous quarantine measures are now in place to prevent the entry of harmful weeds, diseases, and pests through plant introductions?
11. Are you aware that plant introduction can aid in the conservation of genetic variability by providing access to diverse germplasm?
12. Can you believe that hybridization involving introduced plants has significantly contributed to the development of improved crop varieties, including many semidwarf wheat and rice varieties?
13. Did you know that plant introductions can support scientific studies, such as research on biosystematics and plant evolution, by providing new plant types for analysis?
14. Have you heard that some ornamental plants, initially introduced for aesthetic purposes, have become invasive species in their new environments?
15. Are you aware that plant introduction has played a crucial role in expanding agricultural options, including the introduction of crops like soybeans, sugarbeet, and oil palm into new regions?