Genomic constitution of a partial amphiploid OK7211542 used as a source of immunity to barley yellow dwarf virus for bread wheat

A combination of genomic in situ hybridization (GISH) and meiotic pairing analysis of crosses between a series of 2n = 56 partial amphiploids confirmed that the alien genome of the BYDV-immune Agrotricum line OK7211542 is derived from Thinopyrum ponticum and not from Thinopyrum intermedium. The evidence from meiotic pairing analysis indicated that the chromosome constitution of OK7211542 is similar to another Agrotricum line, ORRPX, which was derived from a cross of wheat and Th. ponticum, but different from other Agrotricum lines, Zhong 5 and TAF 46 which were derived from the crosses between wheat and Th. intermedium. The GISH analysis confirmed that OK7211542 contained one complete set of 14 Th. ponticum chromosomes, in which no S chromosome was present in the alien genome. GISH also detected a small alien translocation attached to one of the wheat chromosomes, a result that was consistent with the pairing data.