The Selection of Secondary Tritipyrum Genotypes by Genomic In Situ Hybridization (GISH)

The genomic in situ hybridization (GISH) has been used to identify euploidy and aneuploidy in segregation generations of various plants. In this study, the GISH with minor modifications including, slide preparation of putative secondary Tritipyrum (F2) root meristemic cells, labeled genomic DNA of Thinopyrum bessarabicum by fluorescein 12-dUTP nucleotide as probe, genomic DNA of Thinopyrum bessarabicum for in situ hybridization on root meristemic cells of F2 (2n=6x=42, AABBDEb) and unlabeled Chinese Spring cultivar in pre hybridization, was carried out for the first time in Iran. The results not only indicated the various Eb chromosomes in putative 6x secondary Tritipyrum plants, but also showed different numbers of A, B and D chromosomes. The range of aneuoploidy in F2 genotypes was from %30 to %66.7, which could be due to various numbers of Eb and D chromosomes in each genotype. The selfing or back crossing of F2 plants with bread wheat varieties could lead to chromosomal stability and aneoploidy reduction in secondary Tritipyrum genotypes.