Frequency of 1RS.1AL and 1RS.1BL Translocations in United States Wheats

Translocations of the short arm of rye ( Secale cereale L.) chromosome IR in wheat ( Triticum aestivum L. em Thell.) offer several resistance genes, and possibly increase yield, but adversely affect bread‐making quality. The objective of this study was to determine the frequency of such translocations in wheats bred in the USA. Two hundred and seven entries in six major 1989 wheat nurseries and 30 entries in the 21st International Winter Wheat Performance Nursery were cytologically screened using C‐banding. Among USA wheats, 4.3% had the IRS.1AL translocation and 7.1% had the 1RS.1BL translocation. In the international nursery, 38.1% of lines had the IRS.IBL translocation and one line, ‘TAM 200’ from Texas, had the 1RS.1AL translocation. In addition, several translocations between wheat chromosomes were detected. This information may aid wheat breeders in selection of crossing partners in crossing blocks.