In this article we will discuss about:- 1. Meaning of Single Seed Descent Method 2. Breeding Procedure of Single Seed Descent Method 3. Merits and Demerits.
Meaning of Single Seed Descent Method:
A breeding procedure used with segregating populations of self-pollinated species in which plants are advanced by single seeds from one generation to the next is referred to as single seed descent method.
This method was suggested by Goulden (1939) for advancing segregating generation of self-pollinated crops. Later on this method was applied by Grafius (1965) in oats, Brim (1966) in soybean, and several other workers in soybean, wheat, barley oats, rice, chickpea, green-gram and some other crops.
Breeding Procedure of Single Seed Descent Method:
This is a modified form of bulk breeding method. In this method, only one seed is selected randomly from each plant in F1 and subsequent generations. The selected seed is bulked and is used to grow the next generation. This process is generally continued upto F5 generation. By this time desired level of homozygosity is achieved.
In F6 large numbers of single plants (400-500) are selected and their progeny are grown separately. In F7 and F8, selection is practised between progeny and superior progeny are isolated based on preliminary replicated trial. The superior progeny are then tested in multi-location trials and the best progeny is identified for release.
Merits and Demerits of Single Seed Descent Method:
Merits:
1. This is a simple, convenient, less expensive and time saving method. There is no need of keeping much record in this method.
2. Large number of crosses can be evaluated by this method, because less space and labour is required in each generation.
3. This method is able to retain considerable variability in a breeding population.
4. The material can be rapidly advanced by growing the same in green house.
Demerits:
1. This method does not provide opportunity to practise selection for superior plants till F5 generation. Thus many superior plants may be lost.
2. The frequency of getting desirable genotypes in the advanced generation is reduced in this method.
3. The identity of superior F1 plants cannot be maintained in this method, their identity is lost.
4. The method is more useful when several generations can be grown per year. This method is applicable to self-pollinated crops only.
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