Chromosome locations of leaf rust resistance genes in selected tetraploid wheats through substitution lines.

Langdon durum D-genome disomic substitution lines were used to study the chromosome locations of adult-plant leaf rust resistance genes identified from tetraploid wheat accessions. The accessions are 104 (Triticum turgidumsubsp.dicoccumvar.arras) and 127 (T. turgidumsubsp.durumvar.aestivum). The complete sets of the substitution lines were crossed as female parents with the accessions and F₁ double monosomic individuals selected at metaphase I. Segregating F₂ individuals were inoculated during the flag leaf stage with pathotype UVPrt2 ofPuccinia triticina. The substitution analysis involving accession 104 showed that the gene for leaf rust resistance is located on chromosome 6B. The analysis with accession 127 indicated that chromosome 4A carries a gene for leaf rust resistance. The two novel genes are temporarily designated asLrac104andLrac127, respectively from accessions 104 and 127. [ABSTRACT FROM AUTHOR]