Virulence of Puccinia recondita f. sp. tritici in the United States during 1988-1990

Isolates of Puccinia recondita f. sp. tritici were obtained from wheat leaf collections made by cooperators throughout the United States and from cereal rust field surveys of the Great Plains, Ohio Valley, and Gulf Coast states in 1988, 1989, and 1990. Forty-one virulence/avirulence phenotypes were found among 618 isolates in 1988, 45 among 983 isolates in 1989, and 53 among 906 isolates in 1990 on 14 host lines with single designated genes for leaf rust resistance. The frequencies of virulence to lines with Lr11 and Lr26 during 1988-1990 were greater than in previous years(.)