Plant exploration, germplasm collection, conservation and utilization
Plant Exploration and Germplasm Collection
Plant Biodiversity and Conservation (Theory-Elective)
Department of Agroforestry and Environmental Science
Sylhet Ahricultural University, Sylhet-3100
Syed Zahid Hasan
Faculty of Agriculture
Plant exploration and germplasm collection
• Germplasm Exploration
• Germplasm Collection
• Germplasm Conservation
• Germplasm Evaluation
• Germplasm Utilization
What we will know ?
A germplasm is a collection of
genetic resources for an
Plant exploration is the act
of searching plants or plant
parts for the purpose of
discovery of information or
resources about the plants.
Germplasm exploration & Collection
Exploration and collection:
This process takes into accounts six important items-
1) Sources of collection:
i) Centre of diversity, ii) Gene banks, iii) Gene sanctuaries,
iv) Seed companies, and v) Farmers field’s.
2) Priority of collection: The crop species which are in more risk will get priority to collect first.
3) Agencies of collection: For global collection; International Plant Genetic Resources Institute
4) Methods of collection: Four principle:
i) Through expeditions to the areas, ii) By personal visit,
iii) Through correspondence and iv) Through exchange of material.
5) Methods of sampling: 2 sampling methods; i) Random sampling and ii) Biased sampling
6) Sample size: 50 to 100 individuals should be collected per site with seeds per plant.
Germplasm exploration & Collection
Why we will collect germplasm ?
We will collect germplasm in a given area are that:
It is in danger of genetic erosion or even
A clear need for it has been expressed by the
users, at national level or internationally.
More needs to be known about the germplasm.
The germplasm collection of any crop consists of diverse
types of collections such as:
2. Those derived from areas of cultivation
(a) Commercial types,
(b) Obsolete varieties,
(c) Primitive varieties, and
(d) Special purpose types.
1.Those derived from centres of diversity
(a) Primitive cultivars,
(b) Natural hybrids between cultigen and
(c) wild relatives,
(d) Wild relatives (wild and weedy races) and
(e) Related species and genera.
3. Those derived from breeding programmes
a) Pure line from farmer's stock,
b) Elite varieties or hybrids,
c) Breeding lines,
e) Polyploids, and
f) Intergeneric and interspecific hybrids.
Types of collection:
Multi-species VB. species-specific collecting:
A region is targeted and an attempt is made to sample as much as
possible of the diversity of as many species as possible.
Wild species vs. crop collecting:
For wild species, the collecting window will be much narrower,
because ripe seeds are generally quickly shed and are usually not
For crop, collecting from farmers' fields.
Single-visit vs. multiple-visit collecting:
A region in the timing of fruiting, due to latitudinal, altitudinal and
High Medium Low
A B C
Wheat, Rice Maize, Barley -
Sorghum, Pearl millet Prosomillet & others Amaranth, Buckwheat
Chickpea, Pigeon pea Lentil Soybean, Winged bean
Groundnut, Sesame, Mustard Safflower Niger
Cotton Jute Kenaf/Mesta (Jute)
Citrus, banana Mango, Jackfruit, Egg plant -
Coconut, sugarcane Tea, arecanut, turmeric, Ginger
Table 1: Crop collecting priorities in national context (Arora, 1988)
Which germplasm will get priorities for collection locally ?
Plant species collection Germplasm collection
1. Wide range of species collected. 1. Narrow range of taxa-crop and wild plants
2. Specific and supra-specific categories
2. Material collected mainly at infra-specific
3. Variation represented in commonly available
3. Variation represented in Commonly available
and rare plants.
4. Functional unit is species. 4. Functional unit is a population.
5. Data recorded on limited scale. 5. Data recorded on lvast scale.
6. Material collected and preserved as dried,
mounted and identified specimens in Herbarium.
6. Material collected as seed, pollen, embryos,
vegetative tissue for multiplication/
Table 2: Comparison between Plant species collection & Germplasm collection)
What is the differences between Plant species collection & Germplasm collection ?
Things to be consider:
Seed and vegetative samples should be checked on a regular basis
for insect and fungal attack.
If seed samples (or other material) are being actively dried, silica
gel may have to be changed and dry samples removed.
Samples of fleshy fruits in plastic bags will need to be aerated
Drying papers in herbarium presses must be changed every couple
Samples may need to be sent back to the gene bank at various
during the course of the mission.
Collating, completing and editing the collecting data.
distributing the germplasm samples, reference and collecting data.
Germplasm collecting strategies (Hawkes, 1980):
A. For seed collections (cultivated and wild species):
1. Collect from 50 individuals per site.
2. Sample as many sites as possible according to availability of time.
3. Choose sampling sites over as broad an environmental range as possible.
4. Change tactics for wild species where necessary.
5. If morphological variation is present, make separate samples of each
6. Add biased sampling if some morphotypes are not included in random
7. Take whole inflorescences, as well as seeds, where necessary.
8. Make herbarium specimens, where possible.
9. Taking photographs of the specimen.
10. Write meticulous field notes.
B. i) For vegetatively propagated cultivated species
1. Sample each distinct morphotype.
2. Repeat at intervals over an area.
3. Supplement with seed collections.
** Give same collection numbers if seeds come from the same plants
as the vegetative samples. If they are bulked use separate
ii) For collecting wild vegetatively propagated species
Collect just a single propagule from each 10-15 individuals as a
Germplasm activities at a glance:
1) Exploration and collection
5) Distribution and
Figure 2: Germplasm selection and process order
What is the need of Conservation ?
• Storage of Economically important, endangered, rare
species and make them available when needed.
• The conventional methods of storage failed to prevent
losses caused due to various reasons.
Methods of Germplasm conservation:
1. In-situ Conservation:
Conservation of the germplasm in their natural habitat.
2. Ex-situ Conservation:
Conservation the germplasm outside their natural habitats.
Conservation of biological material at ultra-low temperature (liquid Nitrogen
at -196 degree).
Two types of cryopreservation:
i) Classical cryopreservation: Cooling is performed in the presence of ice (0.5–
ii) Vitrification: Cooling normally takes place without ice formation.
Where we will apply Cryopreservation ?
• It is ideal method for long term conservation of
• Disease free plants can be conserved and propagated.
• Recalcitrant seeds can be maintained for long time.
• Endangered species can be maintained.
• Pollens can be maintained to increase longitivity.
• Rare germplasm and other genetic manipulations can
Germplasm evaluation is done for potentially useful variability for
further use in genetic enhancement of crops.
It usually includes –
Reaction to biotic and abiotic stresses, such as drought
The information obtained is used for:
Query answering Genetic resources research.
Only a small proportion (<1%) of assembled germplasm
has been used in crop improvement programs.
Reasons for low use of germplasm:
Large size of collections.
Lack of data on traits of economic importance, which
shows high genotype × environment interaction.
Restricted access to the germplasm collections.
Inadequate linkages between genebank and users.
Enhancing germplasm utilization :
Developed core and mini core collections of all mandate crops.
Evaluated mini core collections extensively for agronomic and
nutritional traits for utilization in crop improvement program.
Characterized about 98 % cultivated accessions.
Developed trait-specific genepools.
Developed composite collections and reference sets of genetically
most diverse accessions.
You will find something more in woods than in books. (St. Bernard)