C-banding pattern and powdery mildew resistance of Triticum ovatum and four T. aestivum-T. ovatum chromosome addition lines

Summary C-banding patterns of T. ovatum (Ae. ovata) and four T. aestivum cv Poros-T. ovatum chromosome addition lines are presented, and the added chromosomes of T. ovatum have been identified. Furthermore, nucleolar activity and powdery mildew resistance were analyzed in the Poros-ovatum addition lines and compared to that of T. ovatum and T. aestivum cv Poros. The addition lines II, III and IV and Poros were highly susceptible to powdery mildew isolates nos. 8 and 9, whereas the addition lines VI₁ and VI₂ showed high resistance. Even for an Ml-k virulent isolate, these two lines were highly resistant. By combining the cytological results and those of the powdery mildew analysis, the added chromosomes of T. ovatum can be excluded from responsibility for the high powdery mildew resistance of the addition lines VI₁ and VI₂. The same is true for a modified chromosome 6B, which is present in the Poros-ovataum addition lines II, III and VI. The high variation in C-banding pattern observed in the A-, B- and D-genome complement of the addition lines is believed to be the result of crossing different lines of T. aestivum instead of Poros alone. Thus, we cannot trace the powdery mildew resistance back to a specific chromosome.