Development of a genomic in situ hybridization method using Technovit 7100 sections of early wheat embryo

It is difficult to observe the behavior of chromosomes in early wheat embryos because they are wrapped in several cell layers of the ovary. Here we conducted genomic in situ hybridization on sections of ovary embedded in Technovit 7100, a resinous compound suitable for in situ hybridization of mRNA in sectioned tissues. With this resin it is possible to make thin sections with high resolution, no autofluorescence, and good water permeability. These features enable histochemical study using fluorescence microscopy. We established the most suitable conditions for the denaturation of target DNA embedded in Technovit resin, and performed GISH on them. Using this method, we identified Leymus mollis chromosomes in the young ovary of F₁ hybrids between wheat and L. mollis. Furthermore, we observed the behavior of maize chromosomes in early wheat × maize hybrid embryos.