Wheat cv. Idaed 59 has specific resistance to P. graminis f. sp. tritici conditioned by gene SrTt-1 that is associated with the resistance mechanisms of slow rusting and low receptivity to infection by rust races virulent for SrTt-1. The link between slow rusting and SrTt-1 purportedly was broken in a previous study in which a few progenies from 'Baart'/'Idaed 59' were characterized as having srTt-1 combined with slow rusting and SrTt-1 with fast rusting. The seedling responses of 2 such progenies were reexamined by infection tests with cultures of races 151-QSH and 15-TLM, which are avirulent and virulent on SrTt-1, respectively. The slow-rusting line resembled 'Idaed 59' in that it had the seedling resistance conditioned by SrTt-1 to race 151-QSH and low receptivity to infection by race 15-TLM. The fast-rusting line resembled 'Baart' in that it was fully susceptible to both races. Thus, the resistance mechanisms in 'Idaed 59' were not separated, and the relationships among them remain unclear.