Diallel cross

Genetic model

A diallel cross is a mating scheme used by plant and animal breeders, as well as geneticists, to investigate the genetic underpinnings of quantitative traits.[1][2]

In a full diallel, all parents are crossed to make hybrids in all possible combinations. Variations include half diallels with and without parents, omitting reciprocal crosses.[3] Full diallels require twice as many crosses and entries in experiments, but allow for testing for maternal and paternal effects.[4] If such "reciprocal" effects are assumed to be negligible, then a half diallel without reciprocals can be effective.

Common analysis methods utilize general linear models to identify heterotic groups,[5] estimate general or specific combining ability,[6][7] interactions with testing environments and years, or estimates of additive, dominant, and epistatic genetic effects[8][9] and genetic correlations.[10]

## Mating designs

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There are four main types of diallel mating design:

1. Full diallel with parents and reciprocal F1 crosses
2. Full diallel as above, but excluding parents
3. Half diallel with parents, but without reciprocal crosses
4. Half diallel without parents or reciprocal crosses

## References

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1. ^ Hallauer, A. R. and J. B. Miranda Filho. 1988 Quantitative genetics in maize breeding. 2nd ed. Iowa State University Press, Ames, IO.
2. ^ Crusio WE, Kerbusch JM, van Abeelen JHF (January 1984). "The replicated diallel cross: a generalized method of analysis". Behavior Genetics. 14 (1): 81–104\. doi:10.1007/BF01066070. PMID 6712552. S2CID 26899703.`{{cite journal}}`: CS1 maint: multiple names: authors list (link)
3. ^ Jones, R. M. (1965). "Analysis of variance of the half diallel table". Heredity. 20 (1): 117–121\. doi:10.1038/hdy.1965.12.
4. ^ Crusio WE (December 1987). "A note on the analysis of reciprocal effects in diallel crosses". Journal of Genetics. 66 (3): 177–185\. doi:10.1007/BF02927711. S2CID 35147905. Retrieved 2009-08-14.
5. ^ Griffing, B. 1956. Concept of general and specific combining ability in relation to diallel crossing systems. Australian Journal of Biological Sciences 9: 463-493
6. ^ Gardner, C. O. and S. A. Eberhart. 1966. Analysis and interpretation of the variety cross diallel and related populations. Biometrics 22: 439-452
7. ^ Sprague G. F., and L. A. Tatum. 1942. General vs. specific combining ability in single crosses of corn. J. Am. Soc. Agron. 34: 923-932
8. ^ Hayman, B. I. 1954. The analysis of variance of diallel tables. Biometrics 10: 235-244
9. ^ Hayman BI (November 1954). "The theory and analysis of diallel crosses". Genetics. 39 (6): 789–809\. doi:10.1093/genetics/39.6.789. PMC 1209689. PMID 17247520. Retrieved 2010-03-02.
10. ^ Crusio WE (January 1993). "Bi- and multivariate analyses of diallel crosses: a tool for the genetic dissection of neurobehavioral phenotypes". Behavior Genetics. 23 (1): 59–67\. doi:10.1007/BF01067554. PMID 8476392. S2CID 37158435.