In this article we will discuss about:- 1. Purpose of Plant Introduction 2. Procedure of Plant Introduction 3. Agencies 4. Merits and Demerits 5. Achievements.
Plant introduction is a process of introducing plants (a genotype or a group of genotypes) from their own environment to a new environment.
The process of introduction may involve new varieties of crop or the wild relatives of crop species or totally a new crop species for the area.
Introduction may be classified into two categories:
When the introduced variety is well suited to new environment then it is released for commercial cultivation without any alteration of genotype. For example, dwarf wheat varieties like ‘Sonora-64’, ‘Lerma rojo’ and dwarf rice varieties like ‘Taichung Native 1’, ‘IR-8’ are the examples of primary introduction.
When the introduced variety is subjected to Selection or used in hybridization programme with local varieties to get the improved varieties with some new characters introduced called secondary introduction. For example, the varieties like ‘Kalyan Sona’ and ‘Sonalika’ of wheat have been selected from material introduced from CIMMYT, Mexico.
The process of plant introduction is the successful compliance of two important aspects, viz., domestication and acclimatization. Domestication is the process of bringing of a wild species under cultivation by making them changed in behaviour suitable for new environment.
Acclimatization is the ability of a crop to become adapted to a new climatic and edaphic condition.
The process of acclimatization leads to increase the frequency of most adapted genotypes which depends on three factors:
(a) Breeding system,
(b) Genetic variation,
(c) Duration of the crop.
The success of acclimatization depends on two factors like:
(i) Place effect,
(ii) The selection of new genotypes.
Purpose of Plant Introduction:
(a) Use in Agriculture, Forestry and Industry:
New varieties of plants or crops are introduced from various places for use as food, fibre, wood or medicinal purposes as well as the breeding material for hybridisation work.
(b) For Aesthetic Interest:
Various ornamental plants are introduced for beautification.
(c) For Germplasm Conservation:
The spread of high yielding varieties causes a danger to old varieties to get lost from an area. But germplasm collection and conservation help to maintain lines, clones, mutants, cultivars, etc. from as many sources as possible.
(d) For Studying Origin and Distribution:
The distribution of crop plants and their various forms in different parts of the world gives an idea of their origin and evolution.
Procedure of Plant Introduction:
Plant introduction procedure consists of following steps:
(a) Plant procurement or procurement of Germplasm,
(b) Packaging and despatch,
(c) Entry and plant quarantine,
(f) Multiplication and distribution.
(a) Ways of Procurement of Plants or Germplasm:
Requisition for introduction of new crop plant or new varieties should be submitted to NBPGR (National Bureau of Plant Genetic Resources) within the country or to 1BPGR (International Bureau of Plant Genetic Resources). The material may be obtained on an exchange basis from friendly countries either directly or through F.A.O. or the material can also be purchased or obtained as free gift from individuals or organizations.
(b) Packaging and Despatch:
The part of the plant for propagation of that species is known as propagule. The propagule may be seeds, tubers, runners, suckers, stolons, bulbs, root cuttings, buds or seedlings depending upon the crop species. Depending on the type of propagule those are cleaned from other weed-seeds and contaminants and treated with fungicides, packed carefully and despatched so that it can reach the destination in viable condition.
(c) Entry and Plant Quarantine:
On receipt of the material the entry inspection is done by the country for other contaminants and the presence of insect, diseases, nematodes are checked. The materials are treated with insecticides, fungicides or nematicides and then released to the user. The general objective of all ‘quarantine and regulatory’ measures is to prevent pests and diseases from entering into the country as well as to check spreading further.
After quarantine the introduced specimen is given a number regarding species, variety, place of origin and the data are recorded.
The plant materials are classified into three groups:
1. Exotic collection – prefix ‘EC’
2. Indigenous collection – designated as TC’
3. Indigenous wild collection – marked as TW’.
To assess the potential of new introductions, their performance at different substations are evaluated as well as resistance to diseases and pests are evaluated under different environments.
(f) Multiplication and Distribution:
Promising introduced materials are propagated and then released as varieties after necessary trials.
Agencies of Plant Introduction in India:
The central plant introduction agency in India is National Bureau of Plant Genetic Resources (NBPGR), which has its headquarters at New Delhi, but has substations for testing the plant materials. NBPGR has the gene bank for long term storage and future use; it helps to assess the introduced plant material, coordinates the work of other agencies and imparts training in plant collection, introduction and maintenance in India.
The Substations under NBPGR are:
It represents the temperate zone of approx. 2300m above sea level, place for germplasm collection in northern hills, station for acclimatization of material introduced from temperate zone and high altitude.
Exclusively meant for exploring and acclimatizing plant material for arid zone, this is under Central Arid Zone Research Institute.
This substation carries out acclimatization and multiplication of introduced material for central zone of India.
It represents the tropical zone situated at South India.
This centre has been created for collection of germplasm from North-East India.
Other agencies engaged for this purpose are:
Forest Research Institute, Dehradun:
The plant introduction organization set up at the institute looks after introduction, acclimatization, conservation and testing of forest trees.
Botanical Survey of India:
This body is meant for introduction of medicinal plants and also plants for botanical importance.
Different Central Research Institutes as well as Agricultural Universities play the role for collection, introduction and maintenance of germplasm of crop plants.
Merits and Demerits of Plant Introduction:
(a) It provides entirely new crop plants to a place.
(b) Superior varieties may be originated directly or after selection or hybridisation.
(c) Germplasm collection, maintenance and protection of genetic variability are possible through the ways of introduction and exploration.
(d) It is the most quick and economical method of crop improvement when introduced material can be used directly.
(e) Introduction of some varieties to newer areas may protect them from some diseases.
The demerits or disadvantages associated with plant introduction are introduction of weeds, diseases and pests:
(a) The weeds like Argemone, Eichhornia, Lantana have been introduced from other countries with the introduction of crop plants.
(b) The fungal diseases like late blight of potato, flat smut of wheat, coffee rust, bunchy top of banana – all have been introduced in India along with plant materials.
(c) Many insect pests like potato tuber moth, woolly aphis of apple, fluted scale of Citrus were introduced in India along with plant introduction.
However, in most of the cases, the introduction of weeds, diseases and insect pests occurred during a period when quarantine was almost non-existent.
Achievements of Plant Introduction:
The process of introduction from the pre-historic times helped the whole world to achieve newer crop species to new places as well as the new varieties of crop plants.
The examples of achievements are listed below:
(A) New Crop Species:
The crops like potato, maize, groundnut, chillies; coffee, rubber, guava, grape, pineapple, many ornamentals like Gulmohor, Phlox, Salvia, Aster-all have been introduced in India from outside.
(B) New Crop Varieties:
(a) Direct Multiplication and Released as New Varieties:
Dwarf wheat varieties like ‘Sonora 64’, ‘Lerma Rojo’ and dwarf rice varieties like TN-1′, ‘IR-8’ are introduced in India and used directly. There are many more examples of direct release of varieties in other crop plants like oat, soya-bean, tomato, cauliflower, onion, etc.
(b) Selection of Desirable Varieties:
Many varieties have come up after selection from introduced varieties, e.g., ‘Kafyan Sona’, ‘Sonalika’ were selected after introduction of Mexican varieties.
(c) Introduced Varieties as Donor in Hybridization Programme:
Sometimes the introduced varieties, superior than the existing varieties, may be used as donor for disease resistance or pest resistance or stress resistance for plant type and quality characters in hybridization. In case of rice the dwarfing gene from TN-1 or IR-8 have been used for developing, other dwarf rice varieties in rice. All the sugarcane varieties have been derived from introduced noble cane variety of Saccharum officinarum.
(d) Mutation Breeding:
If the introduced material is agronomically superior but lacking a few characters may be treated with mutagen to rectify the defect. For example, ‘Sonora-64’ introduced with red colour grains not accepted by the farmers, the new mutagenic product ‘Sharbati Sonora’ with amber colour grains was produced by M.S. Swaminathan by Gamma- ray treatment.