Genetic Diversity and Migration of Wheat Leaf Rust Populations in Iran Based on Virulence and Molecular Data

Wheat leaf rust agent is a high virulent and moving pathogen. Spores of the pathogen can easity transmitted by air and spread fast on large areas. In this study, the relationship between pathotypes and races of the pathogen and air currents in different geographical areas of Iran was investigated using leaf rust molecular polymorphism and virulence phenotypic data. Virulence factors and molecular structure of eighty-six isolates of wheat leaf rust were determined. The results of molecular and phenotypic data showed that, there were racial and molecular similarity and population migration among most provinces of wheat growing areas. Molecular variance analysis showed that, there was no relationship between population and geographical distribution of races. It was also found that a gene flow, and massive transfer of spores by air currents are exist. Analysis of molecular variance also indicated that each of population was not a separate population, and gene flow was a main factor between them. Study on leaf rust isolates of neighboring provinces showed similar or very close relations among them in South-West to the North-West, North-West to the North-East and North-East to the South-East directions. Each of these directions are affected by one or two air currents that are probably the most important routes of spore movement in the country. It seems that similarity of pathogen populations in the neighboring provinces could be related to the air currents which impact the movement spores through provinces. This path-way is very similar to transmission path of pathogenic yellow rust spores (Yr9), happened in 1993.