Chromosome engineering in wheat to restore male fertility in the msH1 CMS system

Pollen fertility restoration of the CMS phenotype caused by H. chilense cytoplasm in wheat was associated with the addition of chromosome 6H(ch)S from H. chilense accession H1. In order to develop an euploid restored line, different genomic combinations substituting the 6H(ch)S arm for another homoeologous chromosome in wheat were evaluated, with the conclusion that the optimal combination was the translocation T6H(ch)S center dot 6DL. The double translocation T6H(ch)S center dot 6DL in H. chilense cytoplasm was obtained. This line is fertile and stable under different environmental conditions. However, a single dose of the T6H(ch)S center dot 6DL translocation is insufficient for fertility restoration when chromosome 6D is also present. Restoration in the msH1 system is promoted by interaction between two or more genes, and in addition to the restorer of fertility (Rf) located on chromosome 6H(ch)S, one or more inhibitor of fertility (Fi) genes may be present in chromosome 6DL.