Abstract
The gene for adult-plant resistance to race 9 of leaf rust (Puccinia recondita Rob. ex. Desm.) in the common wheat cultivar Thatcher (Triticum aestivum L.) was allelic to Lr22a, a gene for adult-plant leaf rust resistance previously transferred to hexaploid wheat from Aegilops squarrosa L. This gene, designated Lr22b, was linked with Tg, a gene for tenacious glumes, and W21, an inhibitor of waxy foliage, both known to be on chromosome arm 2Dα and linked with Lr22a.