The effect of homoeologous group 7 chromosomes upon adult plant resistance of wheat to yellow rust (<em>Puccinia striiformis</em>).

Aneuploid and intervarietal chromosome substitution lines of wheat cv. Chinese Spring were used to study the effects of homoeologous chromosomes 7A, 7B and 7D upon adult plant resistance to yellow rust (Puccinia striiformis), Chromosomes 7B and 7D carry factors upon their short arms which interact to influence resistance. The results can be explained if there is a single locus determining resistance upon the short arms of chromosomes 7B and 7D. These loci may be homoeo-allelic; however, no evidence was found for a corresponding locus upon the short arm of chromosome 7A. Three homologous variants of the factor 7Ds were found but no variation was found for the factor on 7Bs. [ABSTRACT FROM AUTHOR]