OCCURRENCE AND VIRULENCE OF PUCCINIA-RECONDITA IN CANADA IN 1983

In 1983, wheat leaf rust, caused by P. recondita, was first observed in trace amounts in Manitoba on July 5. By early Aug., leaf rust was abundant on susceptible cultivars where local moisture conditions were favorable, from eastern Manitoba to the Creston valley of British Columbia, but only late fields of the moderately susceptible cv. Neepawa in Manitoba were appreciably damaged. Identification of races from leaf rust survey samples was carried out with 23 differential lines, each with a single gene for resistance. Lines with genes Lr16, Lr19, Lr21, Lr25, Lr26, Lr29 and line T6x PI[plant introduction]58548 were resistant to all survey isolates tested. None of the isolates from Manitoba and Saskatechewan were virulent on adult plants of ''Benito'', which has genes Lr1, Lr2a, Lr12 and Lr13. Sixty-three virulence combinations were identified, using 16 genes for resistance.