Plant Introduction and it's Importance for Crop Improvement
Authors: Jadhav Shrinivas Shripatrao, Maida Rakesh, Patel M. P.
Transference of a genotype or a group of genotype of crop plants from the place of their cultivation in to a new area where they were not being grown previously. Movement of crop varieties from one environment into another within a country is also known as introduction. Some examples of within the country introduction are popularization of Grapes cultivation in Haryana, Wheat in West Bengal, and Rice in Punjab etc. any country cannot be self-sufficient in its needs for plant genetics resources. An average crop genetics resource dependency among various region of the world is more than 50%, and the some region it may be as high 100% for the most important crops.
Types of Plant Introduction
[A] Based on adaptation
1) Primary Introduction - Variety is well adapted to the new environment, released for commercial cultivation without any alteration in the original genotype. Sonora 64, Lerma Roja in wheat and TN-1, IR-8 and IR-36 in rice.
2) Secondary Introduction - Introduced variety may be subjected to selection & hybridization to isolate a superior variety. Kalyan Sona and Sonalika wheat varieties selected from material introduced from CIMMYT, Mexico.
[B] Based on utilization
1) Direct Introduction - New variety takes no time for establishment.
2) Indirect Introduction - New variety takes some time for establishment.
Objectives of Plant Introduction
• To introduce new plant species there by creating ways to build up new industries. e.g. Oil palm
• To introduce high yielding varieties to increase food production. e.g. Rice and wheat.
• To enrich the germplasm collection. e.g. Sorghum, Groundnut.
• To get new sources of resistance against both biotic and abiotic stresses.
Plant Introduction Agencies in India
In India centralized plant introduction agency was initiated at IARI in 1946 at New Delhi. In 1956 it was expanded as the "Plant Introduction and Exploration Organization" and in 1961, it was made an independent division in IARI as the "Division of Plant Introduction". In 1976 division was reorganized as NBPGR. This bureau is responsible for the introduction and maintenance of germplasm of agricultural and horticultural crops. In addition to bureau there are some other agencies, i) FRI, ii) Botanical Survey of India, iii) The Central Research Institute e.g. Tea, Coffee. Sugarcane, Potato, Tobacco etc.
These substations represent the various climatic zones of India: -
1.Shimla, for temperate zone
2. Jodhpur, for arid zone
3. KanyaKumari, for tropical zone
4. Amravati, for mixed climatic zone (now shifted from Akola)
In addition, a new substation has recently been established at Shillong for collection of germplasm from North-east India. This part of the country has a large genetic variability for several crop species, e.g., rice, citrus, Maize etc.
Activities of NBPGR
• Introduce & supplement of required germplasm from other agencies in other countries.
• Exploration & collection of valuable germplasm.
• Inspection & quarantine.
• Testing, multiplication & maintenance of germplasm.
• Publishing its exchange & collection list.
• Setting up natural gene sanctuaries.
• Maintenance of record of introduced plants.
• To supply on request germplasm of various scientists or institution.
• Improvement of medicinal and aromatic plants.
Sources of Plant Introduction
• Centre of diversity
• Gene bank
• Gene sanctuaries
• Seed companies
• Farmers' field
Procedure of Plant Introduction
• Procurement of germplasm - Any individual or institution can introduce germplasm in India. But all the introductions must be routed through the NBPGR, New Delhi. There are two routes for plant introduction. In first route the individual or the institution makes a direct request to an individual or institution abroad. In second procedure the individual or institute submits his germplasm requirements to the NBPGR with a request for their import.
• Quarantine - Quarantine means to keep materials in isolation to prevent the spread of diseases, weed etc. all the introduced is materials thoroughly inspected for contamination with weeds, diseases and insect pests. The materials is fumigated or treated to avoid the contamination. If necessary, the materials are grown in isolation for observation of diseases, insect pests and weeds.
• Cataloguing - Accession number is given to a new introduced material. Information regarding name of species & variety, place of origin, adaptation & its various features are also recorded. Cataloguing of germplasm collections is published by gene bank. The introduced materials are of 3 types & given a prefix- EC - Exotic Collection; IC - Indigenous Collection; IW -Indigenous Wild.
• Germplasm Evaluation - The introduced material is evaluated to assess the potential of new introduction and their performance. These materials are evaluated at different substation. The material resistance to disease and pest is evaluated under favourable environment conditions, and the promising one is either released as such as a variety or subjected to selection or hybridization.
• Multiplication & Distribution - Promising introductions or selections from the introductions may be increased and released as varieties after the necessary trials. Most of the introductions, however, are characterized for desirable traits and are maintained for future use. Such materials are used in crossing programmes and are readily supplied by the bureau on request.
The process that leads to the adaptation of a variety to a new environment is known as acclimatization. Generally, the introduced varieties perform poorly because they are often not adapted to the new environment. Sometimes, the performance of a variety in the new environment improves with the number of generations grown. Acclimatization is brought about by a faster multiplication of those genotypes (present in the original population) that are better adapted to the new environment. Thus acclimatization is essentially natural selection.
The extent of acclimatization is determined by
(1) The mode of pollination,
(2) The range of genetic variability present in the original population,
(3) The duration of life cycle of the crop and
Cross-pollination leads to far greater gene recombinations than self-pollination. As a result cross - pollination is much more helpful in acclimatization than self pollination.
Purpose of Plant introduction
The main purpose of plant introduction is to improve the plant wealth of the country. The chief objectives of plant introduction may be grouped as follows.
1. Entirely New Crop - Plant introductions may provide an entirely new crop species. Many of our important crops, e.g., Maize, potato, tomato, Tobacco, etc., are introductions. Some recently introduced crops are Soybean, sarson, oil palm etc.
2. New Varieties - Sometimes introductions are directly released as superior commercial varieties. The Maxican semi-dwarf wheat varieties Sonora 64 and Lerma Rojo, semi drawf rice varieties TN 1, IR- 8 and IR - 36 are more recent examples of this type.
3. Utilization in Crop Improvement programme - Often the introduced material is used for hybridization with local varieties to develop improved varieties. Pusa Ruby tomato was derived from a cross between Meeruty and Sioux, an introduction from U.S.A.
4. Save the Crop from Diseases and Pests - Sometimes a crop is introduced into a new area to protect it from diseases and pests. Coffee was introduced in South America from Africa to prevent losses from leaf rust.
5. Utilization in Scientific Studies - Collections of plants have been used for studies on biosystematics, evolution and origin of plant species. Vavilov developed the concept of centers of origin and that of homologous series in variation from the study of a vast collection of plant types.
6. Used For Aesthetic Value - Ornamentals, shrubs and lawn grasses are introduced to satisfy the finer sensibilities of man. These plants are used for decoration and are of great value in social life.
• Crops are cultivated extensively after their introduction as new crop species.
• Introductions have been directly released as variety.
• Varieties selected from introduction
• Introduction helps to develop varieties through hybridization.
Merits of Plant Introduction
• Entirely new crop plant is derived.
• It provide new crop varieties.
• Quick & economical method of crop improvement.
• Protection of crops from damage by introducing them in to disease free areas.
• Development of superior varieties through selection & hybridization by using introductions.
Limitation of Plant Introduction
• Introduction of weeds along with introduced materials.
• Introduction of diseases along with introduced materials.
• Introduction of insect pest along with introduced materials.
• Some plants introduced as ornamental species became noxious weeds.
• Some introduced plants are threat to the ecological balance.
About Author / Additional Info:
I am Ph.D. Research Scholar in Genetics and Plant Breeding, Studding in C. P. Collage of Agriculture, Sardarkrushinagr Dantiwada Ahricultural University (Shrinivas.firstname.lastname@example.org)