Population genetic structure of Gibberella zeae isolated from wheat in Argentina

Abstract

Gibberella zeae (anamorph Fusarium graminearum) causes Fusarium head blight of wheat. The authors used amplified fragment length polymorphisms (AFLPs) to characterize the genetic structure of two G. zeae populations from commercial wheat fields. The working hypothesis was that sufficient genetic exchange occurs between local populations to prevent significant partitioning of allelic variation. We analysed 216 AFLP loci for 113 isolates collected during the 2002 harvest season. All strains had AFLP profiles typical of G. zeae lineage 7. Both populations were genotypically diverse but genetically similar and potentially part of a larger, randomly mating population, with significant genetic exchange probably occurring between the two subpopulations. Linkage disequilibrium was low, but higher than reported for many other populations of G. zeae, and about 20% of the alleles detected were specific to one of the two subpopulations—results consistent with limited gene exchange between the two subpopulations. This study extends previous work with populations of G. zeae to include those found in Argentina, one of the world's largest wheat growing countries.

Keywords:

• Amplified fragment length polymorphisms (AFLPs)
• wheat
• gene flow
• genetic diversity
• Gibberella zeae
• random mating.

Acknowledgements

Work was supported by Fundacion Antorchas Grant No. 14056-17, FONCyT (Agencia Nacional de Promoción Científica y Tecnológica) Grant No. PICT 8-14552, the US Wheat and Barley Scab Initiative, and the Kansas Agricultural Experiment Station, Manhattan, Manuscript No. 07-159-J from the Kansas Agricultural Experiment Station.