Permanent Spreading of 1RS.1AL and 1RS.1BL Translocations in Modern Wheat Breeding.

Wheat-rye translocations 1RS.1BL and 1RS.1AL are used in bread wheat breeding worldwide because a short arm of rye chromosome 1 (1RS) when introgressed into the wheat genome confers resistance to diseases, pests and better performance under drought-stress conditions. However, in durum wheat genotypes, these translocations occur only in experimental lines, although their advantages could enhance the potential of this crop. P.P. Lukyanenko National Grain Centre (NGC) has successfully developed commercially competitive cultivars of bread and durum wheat demanded by many agricultural producers in the South of Russia for decades. Here, 94 accessions of bread and 343 accessions of durum wheat, representing lines and cultivars from collection, competitive variety trials and breeding nursery developed at NGC were screened for 1RS using PCR markers and genomic in situ hybridization. The 1RS.1BL and 1RS.1AL translocations were detected in 38 and 6 bread wheat accessions, respectively. None of the durum wheat accessions showed translocation, despite the fact that some of them had 1RS.1BL donors in their pedigree. The absence of translocations in the studied durum wheat germplasm can be caused by the negative selection of 1RS carriers at different stages of the breeding process due to low quality and difficulties in transferring rye chromatin through wheat gametes.