Genetic basis of resistance to Melampsora lini (Pers.) Lev., the agent of flax rust, in domestic varieties of fibre flax

The resistance to diseases may be a more important trait than high productivity in variety, as a damage caused by the pathogen sometimes becomes the limiting factor in cultivation. The first domestic varieties of fibre flax relatively resistant to rust have a polygenic resistance and maintain this property for a long time. An extension of such resistant varieties permitted to reduce the loss of crop and to terminate the lesion by 1998. From 1990, the varieties with short-lived oligogenic resistance are grown, and they currently occupy more than 80 % of acreage. That can be dangerous for flax-growing, if to use the effective resistance genes out of control. For creating varieties with the most reliable protection from the pathogen, secured by effective dominant genes against the background of polygenic resistance, the donor varieties, combining both types of resistance were isolated in N.I. Vavilov Institute of Plant Industry (VIR), and now they may be proposed for use in breeding programs.