Cryptic introgression of Dasypyrum villosum parental DNA in wheat lines derived from intergeneric hybridization

Cytogenetic and DNA molecular analyses have been carried out in 3 wheat introgression lines (ILs; CS x V58, CS x V59, and CS x V60) derived from Triticum aestivum cv. 'Chinese Spring' (CS) x Dasypyrum villosum (Dv) intergeneric hybridization. All lines, which showed several phenotypic differences compared to CS, had the same chromosome number (2n = 42) and structure as CS, and neither chromosomes nor chromatin from Dv were apparently added to their complement. However, Feulgen/DNA cytophotometry showed that there was more nuclear DNA in the lines than in the parental wheat (by 1.85%, 2.76%, and 1.26% in CS x V58, CS x V59, and CS x V60, respectively). Molecular investigation indicated the presence of Dv DNA in the ILs. AFLP analysis of genomic DNA from the ILs, CS, and Dv detected a total of 120 polymorphic bands, of which 7 (5.8%) were present in some or all the ILs and Dv but were absent in CS. PCR amplification, sequence analysis of amplicons, and Southern blot hybridization confirmed the presence of Dv-specific sequences in each of the ILs. These results indicate cryptic introgression of Dv DNA sequences into the genome of the ILs. Some implications of this finding are discussed.