Homoeologous chromosomal location of the genes encoding thionins in wheat and rye.

Thionins are high sulphur basic polypeptides present in the endosperm of Gramineae. In wheat there are three thionins encoded by genes located in the long arms of chromosomes 1A, 1B and 1D. Rye has one thionin encoded by a gene which has been assigned to chromosome 1R after analysis of the Imperial-Chinese Spring rye-wheat disomic addition lines. Commercial varieties and experimental stocks with a 1B/1R substitution carry the thionin from rye (β R) instead of the α B thionin from wheat. The β R thionin gene is not located in the large chromosomal segment representing most of the short arm of chromosome 1R.