Constructing an alternative wheat karyotype using barley genomic DNA.

The established karyotype was generated by genomic in situ hybridization (GISH) using total barley genomic DNA as labelled probe on mitotic metaphase bread wheat chromosomes. GISH produced specific banding signals on 16 of the 21 chromosome pairs. The following chromosomes showed distinctive banding patterns: 2A, 3A, 4A, 5A, 6A, 7A, 1D, 2D, 7D and all of the B chromosomes. The remaining chromosomes showed either faint bands or no hybridization signals at all. The in situ hybridization patterns corresponded to the GAA-satellite sequence, which is similar to the N-banding pattern in wheat. In situ hybridization by labelling total barley genomic DNA made it possible to identify most of the bread wheat chromosomes. The present paper describes a GISH-banding method for hexaploid wheat chromosomes. It is a valuable alternative method for fast chromosome selection without using FISH repetitive DNA clones.