8th INTERNATIONAL WHEAT CONFERENCE

169 have turned out to carry two, two and three pairs of such chromosomes, respectively,
whereas no such chromosome have been revealed for Otrastayuschaya 38. Such type of
hybridization remained stable for the range of the label: block ratio from 1:50 to 1:300
and for different lines of Th. intermedium as a source for the labeled DNA. The same type
of hybridization was observed when GISH was conducted directly at the inbred line of
Th. Intermedium 1119 (kindly provided by Dr. L.I. Glukhova, SEF ‘Snegiri’). This is sure
to be the evidence for that the occurrence of such chromosomes in the Tritipyrum lines
is not due to wheat-wheatgrass translocation. According to the literature the similar type
of banding occurs for wheatgrass chromosomes when GISH is performed with labeled
DNA of Pseudoroegneria sp. that allows to distinguish three subgenomes of Th. intermedium
(Chen, 2005).
The rest of the additional wheatgrass chromosomes in the studied hybrids are characterized
with uniform distribution of the labeled wheatgrass DNA along the length of the
chromosome. However, the chromosome pairs have appeared to differ in absolute size
and centromeric index between each other and between different investigated Tritipyrum
lines. Thus, each studied line of partial wheat-wheatgrass hybrid possesses its own unique
set of additional chromosomes.
Among the analyzed octaploid lines of Tritipyrum the individual plants with telosomics,
wheat-wheatgrass and wheatgrass-wheat translocations have been found which is the
evidence for the continuing segregation of the forms. Since the given wheat-wheatgrass
hybrids are known to be resistant to adverse environmental factors and have been shown
to carry various additional chromosomes of Th. intermedium such kind of chromosomal
rearrangements could play an important role in producing introgressions of useful hereditary
traits into wheat genome.
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