Chromosome location of a gene conferring resistance to Pyrenophora tritici-repentis in Ethiopian wheat cultivars

摘要

In this study, 118 common wheat (Triticum aestivum, 2n = 2× = 42, AABBDD) and durum wheat (Triticum durum, 2n = 4× = 28, AABB) genotypes of Ethiopian origin were evaluated for reaction to tan spot using two Pyrenophora tritici-repentis (Ptr) isolates. Among the commercial Ethiopian bread wheat cultivars HAR604, HAR2562, and Dashen were resistant to both the ASC1a and DW-16 isolates. Inheritance and allelism studies indicated that HAR604, HAR2562 and Dashen possess recessive allelic genes for tan spot resistance. Monosomic F₁ and F₂ analyses using the monosomic lines of Chinese Spring and cultivars HAR2562 and HAR604 indicated that the resistance gene temporarily designated as TsrHar, was located on chromosome 3B. The allelic relationship with the gene now designated Tsr2, formerly tsn2, is unknown. TsrHar should be useful as source of resistance for deployment in conventional breeding schemes.