Production of new races of Puccinia graminis var Tritici

To study the phenon~enon of somatic recombination in stem rust of wheat, seedlings of selected wheat cultivars were inoculated with these six pairs of races: 15CM x 14, 15CM x 17, 15CM x 21, 15CM x 24, 15CM x 42, and 15CM x 117. Recombinants were isolated from only the first two mixtures. As a result of mixing races 15CM x 14, eight races and biotypes were isolated of which three were previously undescribed. From the recombinants of races 15CM x 17, six races and biotypes were identified, of which three were new and previously undescribed.