Knowledge Center Catalog

Population genetics of Mycosphaerella graminicola and Phaeosphaeria nodorum

By: Contributor(s): Material type: TextTextPublication details: Mexico, DF (Mexico) CIMMYT : 1999ISBN:
  • 970-648-035-8
Subject(s): DDC classification:
  • 632.4 GIN
Summary: Restriction fragment length polymorphisms (RFLPs) in the nuclear (nu) and mitochondrial (mt) genomes were used to determine the genetic structure of populations of Mycosphaerella graminicola and Phaeosphaeria nodorum from around the world. Both fungi have genetic structures consistent with a regular sexual cycle and a high degree of gene flow occurring on a global scale. Gene as well as genotype diversity in the nuDNA are high for both fungi. There was no evidence for widespread clones within field populations of either fungus. While both fungi had less diversity in the mtDNA,|M. graminicola exhibited significantly less diversity for the mtDNA compared to P. nodorum. Mycosphaerella graminicola populations from Patzcuaro, Mexico, and Australia exhibited significantly lower gene diversity, suggesting that these populations originated from a limited number of founders. Collections of M. graminicola taken from the same field between 1990 and 1995 showed that genetic drift is negligible, suggesting that effective population sizes are very large. A replicated field experiment showed that selection can cause significant changes in genotype frequencies during the course of a growing season, and that the contributions of immigration and recombination to genetic diversity in field populations can change over the growing season.
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Restriction fragment length polymorphisms (RFLPs) in the nuclear (nu) and mitochondrial (mt) genomes were used to determine the genetic structure of populations of Mycosphaerella graminicola and Phaeosphaeria nodorum from around the world. Both fungi have genetic structures consistent with a regular sexual cycle and a high degree of gene flow occurring on a global scale. Gene as well as genotype diversity in the nuDNA are high for both fungi. There was no evidence for widespread clones within field populations of either fungus. While both fungi had less diversity in the mtDNA,|M. graminicola exhibited significantly less diversity for the mtDNA compared to P. nodorum. Mycosphaerella graminicola populations from Patzcuaro, Mexico, and Australia exhibited significantly lower gene diversity, suggesting that these populations originated from a limited number of founders. Collections of M. graminicola taken from the same field between 1990 and 1995 showed that genetic drift is negligible, suggesting that effective population sizes are very large. A replicated field experiment showed that selection can cause significant changes in genotype frequencies during the course of a growing season, and that the contributions of immigration and recombination to genetic diversity in field populations can change over the growing season.

Conservation Agriculture Program

English

9910|AGRIS 0001

Jose Juan Caballero

INT3034

CIMMYT Publications Collection


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