Uneasy unions: Quality effects of rye chromatin transfers to wheat

A number of genes of agronomic importance have been transferred from rye (S ecale cereale L.) to its close relative, common bread wheat (Triticum aesti vum L). Largely through the production of interspecific chromosomal translo cation and substitution lines, rye chromatin now resides within the genome of a large number of wheat breeding lines and cultivars. Rye chromosomal ma terials have been used to transfer resistance genes to fungal pathogens, es pecially rusts and powdery mildew, resistance to insect peals, and, in some cases, may enhance grain yield, grain yield stability, and grain protein c ontent. Unfortunately, the transfer of some rye chromosomal materials has r esulted in deleterious effects on grain processing quality. This report rev iews the use of various wheat-rye chromosomal translocations and substituti ons in wheat breeding programs, examines the nature of the observed quality defects, and speculates as to their causes and possible means by which the quality effects might be ameliorated.