Persistence of rye (secale cereale L.) chromosome arm 1RS in wheat (triticum aestivum L.) breeding programs of the great plains of north america

Authors: Graybosch, Robert; Bai, Guihua; St Amand, Paul; Sarath, Gautam

Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/26/2019
Publication Date: 3/8/2020
Citation: Graybosch, R.A., Bai, G., St Amand, P.C., Sarath, G. 2020. Persistence of rye (secale cereale L.) chromosome arm 1RS in wheat (triticum aestivum L.) breeding programs of the great plains of north america. Genetic Resources and Crop Evolution. 66:941-950. https://doi.org/10.1007/s10722-019-00742-4.
DOI: https://doi.org/10.1007/s10722-019-00742-4

Interpretive Summary: Wheat and rye, both members of the grass family (Poaceae) are close relatives. Decades ago, wheat geneticists succeeded in transferring pieces of rye chromosomes and DNA to wheat via a process known as “chromosomal engineering.” Wheat cultivars containing rye genes, introduced by this non-GMO method, have been produced worldwide. Most commonly, the rye genes are present in the form of rye chromosome arm 1RS, attached to the long arm of either wheat chromosome 1A or 1B. 1RS carries many useful genes, including those conferring resistance to multiple rusts, powdery mildew, insects and viruses, as well as genes for stress tolerance and agronomic performance. At times, however, the good traits are associated with negative effects on processing quality of flours derived from 1RS-wheats. For the past 25 years, ARS scientists have surveyed advanced Great Plains wheat breeding lines to determine which carry 1RS. Both 1Al.1RS and 1BL.1RS wheats were found in all tested years. 1AL.1RS lines were more common in southern Great Plains breeding programs. 1AL.1RS lines were released as cultivars at a frequency identical to that of wild-type breeding lines. In contrast, 1BL.1RS breeding lines were developed by breeding programs throughout the Great Plains, but fewer were released as cultivars. Both 1RS translocation types persist in Great Plains breeding programs. The lower rate of release of 1BL.1RS cultivars no doubt is a consequence of the more drastic effects on breadmaking quality relative to those observed with 1AL.1RS. The results of this study may be used by wheat breeding programs to select parents for complementary crosses and to continue to exploit the useful genes of 1RS.

Technical Abstract: Rye (Secale cereale L.) chromosome arm 1RS has been used world-wide by wheat (Triticum aestivum L.) breeding programs as a source of pest and pathogen resistance genes, and to improve grain yield and stress tolerance. The most common vehicles used to access 1RS are 1AL.1RS and 1BL.1RS wheat-rye chromosomal translocations. Over the past 25 years, advanced North American wheat breeding lines were evaluated, first by assay of secalin storage proteins, and later by use a DNA marker TSM0120, for the presence of these two translocations. Both methods provide accurate and efficient means of identifying and differentiated 1BL.1RS and 1A.1RS. Both 1Al.1RS and 1BL.1RS wheats were found in all tested years. 1AL.1RS lines were more common in southern Great Plains breeding programs. 1AL.1RS lines were released as cultivars at a frequency identical to that of wild-type breeding lines. In contrast, 1BL.1RS breeding lines were developed by breeding programs throughout the Great Plains, but fewer were released as cultivars. Both 1RS translocation types persist in Great Plains breeding programs. The lower rate of release of 1BL.1RS cultivars no doubt is a consequence of the more drastic effects on breadmaking quality relative to those observed with 1AL.1RS.