| The hexaploids recovered in F2 populations derived from the
fifth backcross pentaploids for Kavkaz and the sixth backcross pentaploids
for Kalyansona (let designate them by MI5KV and MI6KS respectively) were
considered to be very close to MI genotype regarding to their AABB component.
Supporting evidence to this there were the results obtained when comparing
MI with tetraploids recovered in the same F2 populations as the hexaploids
done. No differences were found on morphological characters. Electrophoretic
patterns of gliadins in MI and the recovered tetraploids were identical.
Synthetic hexaploids represent vigorous full-fertile forms (see figure), which are attributed to variety group Semirigidum A. Filat and Dorof. of Triticum aestivum L. subsp. hadropyrum (Flaks.) Tzvel. MI5KV belongs to var. magnificum and MI6KS - var. turanicum according to the classification by DOROFEEV et al. (1979). Chromosome pairing in both of them is similar to that corresponding sources of D genome. Comparison of the synthetic hexaploids with tetraploid MI showed that D genome from both sources increased top internode diameter, length, width and weight of grain and decreased spikelet number per ear and undeveloped spikelet number. Some characters in the hexaploids such as plant height, top internode length, heading time and others deviated from those in MI in plus or minus derections dipending on the sources of D genome. These new hexaploids may provide a new approach to the problem concerning a genetic composition of wheat genomes. They enable us to study durum wheat with monosomic analysis as exactly as it is done in common wheat and identify those genetic changes in common wheat D genome which presumably have taken place within it since incorporation into the complex wheat genome. References DOROFEEV V.F., A.A. FILATENKO, E.F. MIGUSHOVA, R.A. UDACHIN and M.M. YAKUBTSINER.1979. Flora of cultivated plants. Vol.1. Wheat. Kolos press, Leningrad. (In Russian). MCFADDEN E.S. and E.R. SEARS. 1946. The origin of Triticum spelta and its freethreshing hexaploid relatives. J. Hered. 37: 81-89, 107-116. |
| <-- Back |