HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (15) Citing Articles via Google Scholar Google Scholar Articles by Reif, J. C. Articles by Frisch, M. Search for Related Content PubMed Articles by Reif, J. C. Articles by Frisch, M. Agricola Articles by Reif, J. C. Articles by Frisch, M. Related Collections Maize Plant Genetic Resources

PLANT GENETIC RESOURCES

Genetic Diversity Determined within and among CIMMYT Maize Populations of Tropical, Subtropical, and Temperate Germplasm by SSR Markers

^a Institute of Plant Breeding, Seed Science, and Population Genetics, Univ. of Hohenheim, 70593 Stuttgart, Germany
^b Crop Science Dep., Univ. of Illinois, 1102 South Goodwin Avenue, Urbana, IL 61801
^c International Maize and Wheat Improvement Center (CIMMYT), Apdo. Postal 6-641 06600 Mexico D.F., Mexico
^d Institute of Crop Breeding and Cultivation, Chinese Academy of Agric. Sciences, Zhongguancun South Street 12, 100081, Beijing, China

^* Corresponding author (melchinger{at}uni-hohenheim.de).

Genetic diversity in maize (Zea mays L.) plays a key role for future breeding progress. The main objectives of our study were to (i) investigate the genetic diversity within and among CIMMYT maize populations by simple sequence repeat (SSR) markers, (ii) examine genotype frequencies for deviations from Hardy-Weinberg equilibrium (HWE) at individual loci, and (iii) test for linkage disequilibrium (LD) between pairs of loci. Twenty-three maize populations and pools established in 1974, which mostly comprise germplasm from different racial complexes adapted to tropical, subtropical intermediate-maturity, subtropical early-maturity, and temperate megaenvironments (ME), were fingerprinted by 83 SSR markers covering the entire maize genome. Across all populations, 27% of the SSR markers deviated significantly from HWE with an excess of homozygosity in 99% of the cases. We observed no evidence for genome-wide LD among pairs of loci within each of the seven tropical populations analyzed. Estimates of genetic differentiation (G_ST) between populations within MEs averaged 0.09 and revealed that most of the molecular variation was found within the populations. Principal coordinate analysis based on allele frequencies of the populations revealed that populations adapted to the same ME clustered together and, thus, supported clearly the ME structure.

Abbreviations: CIMMYT, International Maize and Wheat Improvement Center • HWE, Hardy-Weinberg equilibrium • ME, megaenvironment • LD, linkage disequilibrium • MRD, modified Roger's distance • PC, principal coordinate • PCoA, principal coordinate analysis • QTL, quantitative trait locus • SSR, simple sequence repeat

This article has been cited by other articles:

				X. M. Fan, H. M. Chen, J. Tan, C. X. Xu, Y. M. Zhang, Y. X. Huang, and M. S. Kang A New Maize Heterotic Pattern between Temperate and Tropical Germplasms Agron. J., June 16, 2008; 100(4): 917 - 923. [Abstract] [Full Text] [PDF]

				M. L. Warburton, J. C. Reif, M. Frisch, M. Bohn, C. Bedoya, X. C. Xia, J. Crossa, J. Franco, D. Hoisington, K. Pixley, et al. Genetic Diversity in CIMMYT Nontemperate Maize Germplasm: Landraces, Open Pollinated Varieties, and Inbred Lines Crop Sci., March 19, 2008; 48(2): 617 - 624. [Abstract] [Full Text] [PDF]