Origin and Phylogenetical Differentiation of Wild Tetraploid Wheats Inferred from Their Susceptibility to Leaf Rust (Preliminary Note) : Susceptibility of the Genus Triticum to Two Races of Puccinia recondita f.sp. tritici

To study the relationship between the origin and phylogenetic differentiation of the tetraploid wheats and their susceptibility to leaf rust, a model experiment has been carried out. Namely, using 8 species which had played an important role on the origin and evolution of the genus Triticum, the seedling reactions of them to 2 races of Puccinia recondita Rob. ex Desm. f.sp, tritici were examined. In the consequence of the test, Tritcium monococcum belonging to the Einkorn. group, l strain of T. dicoccoides belonging to the Emmer group, T. araraticum and T. tinoheevi belonging to the Timopheevi group and 2 strains of T. spelta belonging to the Dinkel group were resistant, T. aegilopoides belonging to the Einkorn group, 1 strain of T. durum belonging to the Emmer group, 1 strain of T. spelta and T. araraticum were susceptible, and 2 strains of T. dicoccoides and 2 strains of T. durumshowed various types of responses to avilulent race 1 B. On the other hand, T. monococcum and T. timopheevi were resistant, 2 strains of T. durum and 1 strain of T. spelta showed several types of reactions, respectively, but other wheat strains were sesceptible to virulent race 21 B .Three wild species except T. aegilopoides showed different reactions to 2 races. Namely they were susceptible to race 21 B in all cases, change of the reactions was observed. As a whole, the tendency to show unstable responses to avirulent race 1 B, but stable ones to virulent race 21 B was recognized.