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Current Category » Breeding of Field and Horticultural Crops

Germplasm Activities - Exploration and Collection

Exploration refers to collection trips and collections refer to to tapping of genetic diversity from various sources and assembling the same at one place.

The exploration and collection is a highly scientific process. This process takes into accounts six important items, viz. 1) Sources of collection, 2) Priority of collection, 3) Agencies of collection, 4) Methods of collection, 5) Methods of sampling and 6) Sample size. These aspects are briefly discussed below:

1. Sources of Collection:

There are five important sources of germplasm collections: viz 1) Centres of diversity, 2) Gene banks, 3) Gene sanctuaries, 4) Seed companies, and 5) Farmers field’s. Moreover, collections can be local exploration trips to the regions of crop diversity.

2. Priority of Collection:

The next important step in the germplasm collection is to fix priority of collection. Some areas of diversity have been threatened more than others by the danger of extinction. Similarly, some crop species have more risk, of extinction than others. Hence, endangered areas and endangered species should be given priority for germplasm collection.

3. Agencies of Collection:

The risk of germplasm collection is undertaken by crop research institutes and state agricultural universities in collaboration with National bureau of plant Genetic Resources. New Delhi for indigenous collections. For global collection the task is undertaken in collaboration with International Plant Genetic Resources, Institute (IPGRI), Rome, Italy.

4. Method of Collection:

Germplasm collections are made in four principal ways: viz. 1) Through expeditions to the areas or regions of genetic diversity, 2) By personal visit to gene bank centre, 3) Through correspondence ,and 4) Through exchange of material.

5. Method of Sampling:

There are two sampling methods for collection of germplasm from the regions of diversity, viz. 1) Random sampling, and 2) Biased sampling, random sampling is effective in capturing of alleles for biotic stresses, whereas non random or biased sampling is useful in collection of morphologically distinct genotypes. Hence, it is advised that both random as well as biased sampling procedures should be adopted to tap the maximum genetic diversity of a crop species.

6. Sample Size:

The sample size should be such that 95% of the total genetic diversity can be captured from the area of collection. To achieve this goal, 50 to 100 individuals should be collected per site with 50 seeds per plant. As wide as possible range of habitats should be sampled for capturing maximum genetic diversity.

 

Current Category » Breeding of Field and Horticultural Crops