Three new rust resistance genes in flax introductions

Abstract The genetics of resistance to flax rust (caused by Melampsora lini) in six flax (Linum usitatissimum) introductions from Argentina were investigated in a series of crosses with single-gene lines for rust resistance. These introductions proved resistant to the most virulent rust races in the North American collection of M. lini. Segregating patterns in F2 and BCF1 populations from crosses with the effective rust resistance genes indicated the presence of three resistance genes designated as Al, A2, and A3. These genes are different from the rust resistance genes present in the 30 single-gene lines used to differentiate the North American races of M. lini