Molecular Breeding

, Volume 20, Issue 2, pp 117–129 | Cite as

Effect of selection on the heterozygosity of inbred lines of maize

  • Bernardo Ordas
  • Maria Cinta Romay
  • William G. Hill
Article
First Online:
Received:
Accepted:

Abstract

Although pedigree selection is the most commonly used method for developing inbred lines of maize, there are no studies on its effect on the heterozygosity of the lines. The objective of this work was to study the effect of pedigree selection on their heterozygosity. Thirteen F5 or F6 maize inbred lines developed by the pedigree selection method in four breeding programs and their F1 and F2 − F4 ancestors were genotyped with simple sequence repeat markers distributed along the genome. Simulation was also conducted assuming different models of selection to investigate the selective forces needed to explain the data. In the F2, F3 and F4 40%, 66% and 86% of the markers segregating in the F1 were fixed; that is, in the F2 and F3 fixation was lower than neutral expectation, but higher in the F4. Due to such opposite apparent directions of selection, the heterozygosity of the lines in the F5 or F6 generations did not differ significantly from neutral expectations. The time to fixation differed from that expected with neutrality for most of the chromosomes, indicating that selection is distributed across the genome; but apparent overdominant effects in chromosome 7 were higher than in other chromosomes. In conclusion, the relationship between heterozygosity and vigour may reduce the effectiveness of pedigree selection in its goal of selecting the more vigorous, homozygous individuals. A more effective procedure is proposed using molecular markers for the identification of the more homozygous individuals, the most vigorous of those individuals being selected.

Keywords

Heterozygosity Inbred line Maize Pedigree selection Simple sequence repeats 
This is a preview of subscription content, log in to check access.

Notes

Acknowledgements

Authors wish to thank Drs LM Reid (Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food, Canada), J Hernandez (Monsanto) and H Cordova (International maize and wheat improvement center, Mexico) for supplying us with seeds. This research was supported by the National Plan for Research and Development of Spain (Project Cod. AGL2001-3946) and the University of Edinburgh. B Ordas acknowledge a fellowship from the Ministry of Science and Education.

References

  1. Austin DF, Lee M (1996) Comparative mapping in F2:3 and F6:7 generations of quantitative trait loci for grain yield and yield components in maize. Theor Appl Genet 92:817–826CrossRefGoogle Scholar
  2. Beavis WD, Smith OS, Grant D, Fincher R (1994) Identification of quantitative trait loci using a small sample of topcrossed and F4 progeny from maize. Crop Sci 34:882–896CrossRefGoogle Scholar
  3. Butrón A, Tarrío R, Revilla P, Malvar RA, Ordás A (2003) Molecular evaluation of two methods for developing maize synthetic varieties. Mol Breed 12:329–333CrossRefGoogle Scholar
  4. Charlesworth D (1991) The apparent selection on neutral marker loci in partially inbreeding populations. Genet Res Camb 57:159–175Google Scholar
  5. Eathington SR, Dudley JW, Rufener II GK (1997) Marker effects estimated from testcrosses of early and late generations of inbreeding in maize. Crop Sci 37:1679–1685CrossRefGoogle Scholar
  6. Edwards MD, Stuber CW, Wendel JF (1987) Molecular marker facilitated investigations of quantitative trait loci in maize 1. Numbers, genomic, distribution and types of gene action. Genetics 116:113–125PubMedGoogle Scholar
  7. Frydenberg O (1963) Population studies of a lethal mutant in Drosophila melanogaster 1. Behaviour in populations with discrete generations. Hereditas 50:89–116CrossRefGoogle Scholar
  8. Gethi JG, Labate JA, Lamkey KR, Smith ME, Kresovich S (2002) SSR variation in important US maize inbred lines. Crop Sci 42:951–957CrossRefGoogle Scholar
  9. Hallauer AR, Sears JH (1973) Changes in quantitative traits associated with inbreeding in a synthetic variety of maize. Crop Sci 13:327–330CrossRefGoogle Scholar
  10. Hallauer AR, Miranda Fo JB (1988) Quantitative genetics in maize breeding, 2nd edn. Iowa State University Press, Ames, pp 10–15, 284–286Google Scholar
  11. Heckenberger M, Bohn M, Ziegle JS, Joe LK, Hauser JD, Hutton M, Melchinger E (2002) Variation of DNA fingerprints among accesions within maize inbred lines and implications for identification of essentially derived varieties. I. Genetic and technical sources of variation in SSR data. Mol Breed 10:181–191CrossRefGoogle Scholar
  12. Hill WG, Robertson A (l968) The effects of inbreeding at loci with heterozygote advantage. Genetics 60:6l5–628Google Scholar
  13. Jenkins MT (1935) The effects of inbreeding and of selection within inbred lines of maize upon the hybrids made after successive generations of selfing. Iowa State Coll J Sci 9:429–450Google Scholar
  14. Kroymann J, Mitchell-Olds T (2005) Epistasis and balanced polymorphism influencing complex trait variation. Nature 435:95–98PubMedCrossRefGoogle Scholar
  15. Laurie CC, Scott DC, LeDeaux JR, McCarroll R, Bush D, Hauge B, Chaoqiang L, Clark D, Rocheford TR, Dudley JW (2004) The genetic architecture of response to long-term artificial selection for oil concentration in the maize kernel. Genetics 2004 (168):2141–2155CrossRefGoogle Scholar
  16. Liu YG, Whittier RF (1994) Rapid preparation of megabase plant DNA from nuclei in agarose plugs and microbeads. Nucleic Acids Res 22:2168–2169PubMedCrossRefGoogle Scholar
  17. Lu H, Romero-Severson J, Bernardo R (2002) Chromosomal regions associated with segregation distortion in maize. Theor Appl Genet 105:622–628PubMedCrossRefGoogle Scholar
  18. Lu H, Romero-Severson J, Bernardo R (2003) Genetic basis of heterosis explored by simple sequence repeat markers in a random-mated maize population. Theor Appl Genet 107:494–502PubMedCrossRefGoogle Scholar
  19. Mackay TFC (2004) The genetic architecture of quantitative traits: lessons from Drosophila. Curr Opin Genet Dev 14:253–257PubMedCrossRefGoogle Scholar
  20. McGoldrick DJ, Hedgecock D (1997) Fixation, segregation and linkage of allozyme loci in inbred families of the Pacific oyster Crassostrea gigas (Thunberg): implications for the causes of inbreeding depression. Genetics 146:321–334PubMedGoogle Scholar
  21. Ohta T (1971) Associative overdominance caused by linked detrimental mutations. Genet Res 18:277–286CrossRefGoogle Scholar
  22. Reif JC, Hamrit S, Heckenberger M, Schipprack W, Maurer HP, Bohn M, Melchinger AE (2005) Genetic structure and diversity of European flint maize populations determined with SSR analysis of individuals and bulks. Theor Appl Genet 111:906–913PubMedCrossRefGoogle Scholar
  23. Robertson A (1962) Selection for heterozygotes in small populations. Genetics 47:1291–1300PubMedGoogle Scholar
  24. Rumbal W, Franklin IR, Frankham R, Sheldon BL (1994) Decline in heterozygosity under full-sib and double first-cousin inbreeding in Drosophila melanogaster. Genetics 136:1039–1049Google Scholar
  25. Schon CC, Utz HF, Groh S, Truberg B, Openshaw S, Melchinger AE (2004) Quantitative trait locus mapping based on resampling in a vast maize testcross experiment and its relevance to quantitative genetics for complex traits. Genetics 167:485–498PubMedCrossRefGoogle Scholar
  26. Sing CF, Brewer GJ, Thirtle B (1973) Inherited biochemical variation in Drosophila melanogaster: noise or signal? I. Single locus analyses. Genetics 75:381–404PubMedGoogle Scholar
  27. Strauss SH (1986) Heterosis at allozyme loci under inbreeding and crossbreeding in Pinus attenuata. Genetics 113(1):115–134PubMedGoogle Scholar
  28. Stuber CW, Lincoln SE, Wolff DW, Helentjaris T, Lander ES (1992) Identification of genetic factors contributing to heterosis in a hybrid from two elite maize inbred lines using molecular markers. Genetics 132:823–839PubMedGoogle Scholar
  29. Veldboom LR, Lee M, Woodman WL (1994) Molecular marker-facilitated studies in an elite maize population: I. Linkage analysis and determination of QTL for morphological traits. Theor Appl Genet 88:7–16CrossRefGoogle Scholar
  30. Wang D, Shi J, Carlson SR, Cregan PB, Ward RW, Diers BW (2003) A low-cost, high-throughput polyacrylamide gel electrophoresis system for genotyping with microsatellite DNA markers. Crop Sci 43:1828–1832CrossRefGoogle Scholar
  31. Wang J, Hill WG (1999) Effect of selection against deleterious mutations on the decline in heterozygosity at neutral loci in closely inbreeding populations. Genetics 153:1475–1489PubMedGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2007

Authors and Affiliations

  • Bernardo Ordas
    • 1
  • Maria Cinta Romay
    • 1
  • William G. Hill
    • 2
  1. 1.Misión Biológica de GaliciaSpanish National Research CouncilPontevedraSpain
  2. 2.Institute of Evolutionary Biology, School of Biological SciencesUniversity of EdinburghEdinburgh UK

Personalised recommendations