Recurrent selection is a plant breeding technique that involves repeated cycles of selection and intermating to improve quantitative traits in a population. There are several types including simple recurrent selection, recurrent selection for general combining ability, and recurrent selection for specific combining ability. Recurrent selection for specific combining ability uses homozygous testers to select for specific combining ability through multiple generations of testing cross performances, selecting best performers, and intermating selections. This allows for systematic accumulation of favorable alleles while maintaining genetic variation to continue making progress from selection.

1. RECURRENT SELECTION
FOR SPECIFIC COMBINING
ABILITY
Speaker: Vipin Kumar Pandey (Ph.D. Scholar)
CLASS PRESENTATION (GP-603)
Presentation Date: 11-1-2018

2. Recurrent Selection:
• The initial idea of recurrent selection was independently given by
Hayes and Garber in 1919 and East and Jones in 1920.
• But the term recurrent selection was first coined by Hull in 1945.
Definition:
Recurrent selection is defined as reselection generation after
generation, with intermating of selected plant to produce the
population for the next cycle of selection.
The idea of this method was to ensure the isolation of superior inbreds
from the population subjected to recurrent selection.

3. The isolation of an outstanding inbred line depends on
two factors:
1) The proportion of superior genotypes present in the base population from
which lines are isolated.
2) The effectiveness of selection during the inbreeding of desirable genes.

4. Types of Recurrent Selection:
i) Simple recurrent selection (SRS)
ii) Recurrent selection for general combining ability (RSGCA)
iii) Recurrent selection for specific combining ability (RSSCA)
iv) Reciprocal recurrent selection (RRS)

5. Simple Recurrent Selection (SRS) :
• A type of recurrent selection that does not
include tester is referred as simple
recurrent selection. It is also known as
phenotypic recurrent selection.

6. Procedure of Simple Recurrent Selection:

7. Case study 1

8. Recurrent Selection for General Combining
Ability (GCA):
A form of recurrent selection used to important the general combining ability of a
population for a character and the heterozygous tester is referred as RSGCA. It is also
known as half sib recurrent selection.

9. Procedure of Recurrent Selection for General
Combining Ability (RSGCA):

10. Recurrent Selection for SCA:
• It was originally proposed by Hull in 1945.
• Its a form of recurrent selection that is used to improve the
SCA of a population for a character by using homozygous
tester is referred as (RSSCA) recurrent selection for
specific combining ability.
• It is also known as half site recurrent selection with
homozygous tester.

11. Procedure:
The selection procedure of this method is same as for RSGCA, except
that the tester is an inbred line which has narrow genetic base i.e tester
used must be an outstanding inbred. The differences in the performance
of test cross are due to difference in their specific combining ability.

12. Recurrent Selection for SCA
• Cyclical selection of populations
form families
evaluate in trials
recombine selections
• Pedigree selection and improvement of elite lines are
also cyclical processes, but the population structure is
not so clearly defined
• Selfing and introgression of new germplasm are
common features of both selection systems
• Recurrent selection and development of lines can be
integrated into a comprehensive system
Bernardo, Chapt. 10

13. Selfing and Recurrent selection
• Selfing systems:
– Fixation of alleles is so rapid that the impact of selection is limited
– Probability of obtaining segregants with all of the favorable alleles
controlling a quantitative trait is small
• Recurrent selection:
– systematically increases the frequency of favorable alleles
– maintains the genetic variation within a population to permit
continual progress from selection
Example: with 5 loci, all alleles have p=0.5
1/32 chance to get all of the good alleles
Example: with 5 loci, all alleles have p=0.5
1/13 chance to get all of the good alleles

15. Case study 2

16. Reciprocal Recurrent Selection (RRS):
A form of recurrent selection used to improve both GCA and SCA of a
population for a character using two heterozygous testers is known as
RRS. It is also known as recurrent reciprocal half sib selection.
Comstock et al. in 1949, proposed this method.
Main Features of these Methods:
1) It is used for improvement of polygenic characters.
2) Selection is made on the basis of test cross performance.
3) Two heterozygous tester are used as a source of population.
4) It is used for improving population for GCA and SCA for specific characters.
5) It is equally effective with incomplete, complete and over dominance.
6) It is used for improvement of those characters, which are governed by both
additive and non-additive gene action.
7) This method also requires three seasons for completion of each cycle of
selection.

17. Procedure:

18. Merits:
1) Recurrent selection is an efficient breeding method for increasing
the frequency of superior genes for various economic characters.
2) It helps in breaking repulsion phase of linkage.
3) It helps in maintaining high genetic variability due to repeated
intermitting of heterozygous population.
Demerits:
1) It is not directly used for the development of new varieties.
2) This method involves lot of selection crossing and selfing work.
3) It permits selfing, which leads to loss of genetic variability.

20. References
• Allard, R. W. 1960. Principles of plant breeding. John Wiley and Sons, inc, new
York.
• Comstock, R. E., Robinson, H. F. and Harvey P. H. 1949. A breeding procedure
designed to make maximum use of both general and specific combining ability.
Agron. J. 41: 360-367.
• Singh, B.D. 2012. Plant breeding principles and methods, Kalyani
Publishers, New Delhi-110002.
• www.agriinfo.in/default.aspx?page=topic&superid=3&topicid=1773