Chromosome Banding And Aneuploidy Technology In The Integrated Use Of Wheat Cytogenetic Study

On the basis of increased study precisenss through combin-ed use of chromosome banding, karyotype analysis, genome analysis and aneuploid technique some original new results were obtained in the studies of origination and evolution of wheat and its relatives and transfer of alien chromosomes into wheat as well. These results were hardly obtainable by seperate use of above-mentioned techniques.In order to study the origin of chromosome 4A and genome B and G of tetraploid wheats, karyotype analysis and chromosome N-banding of the probable A genome donors,T. (?)onococcum, T. boeotic(?), T. (?)rart(?), and the probable donors of genome B and G-A(?). speltoides, Ae, longissi(?)a,Ae. sharonensis, Ae. bicornis and Ae. searsii were carried out.Results showed that no chromosome si(?)ilar to 4A in N—banding pattera was observed in T. (?)onococcu(?), T. boeoticum and T. (?)rart(?). Definite differences in the degree of heterochromati(?)ixation and the distribution of heterochromatin were discovered between A genome chromosomes of tetraploid wheats with AABB or AAGG genomic constitution and the T. (?)onococc(?) chromosomes. This indicated that some differentiation of A genome chromosomes had (?)ccared in the process of its evo(?)ution. The genome B (except (?)) and the genome G (except G(?)) of tetrapleid wheat species showed a high degree of heter(?)chromati(?)ization. obvious differences in karyotype aad handing patterns were observed only between chromossme (?) and G(?), and between 4B and G(?) no such differences appeared between the rest chro(?) sames. Of all the Sitopsis group Aegitops species, karyotype and N-banding patter(?) of Ae. spe(?)eides showed the highest siai(?)arity with B genome (except 4B) and G genome (except G(?)) chromosomes. Only in Ae. spe(?)toides a chromosome fairly sini-lar to the 4A of T. dicoccoides and T. araraticum could be discovered. For further evi(?)ence, double ditelosomics of T. durum had been crossed with T. araraticum and Ae. speltoides, respectively. And meiotic chromosome banding and pairing analysis of handed eiosoaics with corresponding chromosomes of the F(?) hybrids were studied. Results further demonstrated that the B and G genome chromosomes (exc(?)usive of individual exceptions) and chromosome 4A showed rather high homology with the chromosomes of Ae. speltoides. Consequently, it is reasonably suggested that Ae. spettoides could be one of the (?)ost possible (?)onor of B or G genome. Furthermore, chro-mosome 4A obv(?)usly need to be redesignated as 4B and/or G(?) And chromosome 4B is most likely a translocated chromosome involving homo(?)ologo(?)s group 7. As for the chromosome G(?), it is also suppos(?)d to be a translocated chromosome involving the 6AL. Of course, the final determination of the origin, evolution and the homoe(?)logous grouping of the 4B and G(?) stilt need to be studied in the further.The chromosome constitution of endemic hexaploid wheats in Western China was identified by N-banding technique and telosomic pairing analysis at MI of PMC in the F(?) hybrids between T. aestivum c.v. Chinese Spring double ditelosomics and T. aestivum ssp. yunanese or T, aestivum ssp. tibatenum It was revealed that the chromosome constiution of Yunnan wheat and Xizang wheat were basically similar to that of Chinese Spring except (?) of Xizang wheat.In the studies on transferring and identifying alien chromosomes into wheat, (?) combined use of mitotic and meiotic chroBosoae N-banding is also successfully practiced in determination of T. durum - H. villosa amphipoid, five wheat alien disomic addi(?) with H. villosa chromosomes V2, V3, V(?), V(?) or V(?), alien substitution line with chromosome V(?) andsome translocation lines. The gene controlling powdery mildew resistance is preliminarily allocated on the H. villosa diromosome V(?) by morphological and characteristic identification combined with cytogenetical analysis. The genes controlling the trait of clustering brist(?)es on the ridges of glume might be allocated on the chromosome V6 and (or) V7 of H. villosa with the same methodology.By means of crossing Chinese Spring monosomic 6B with diso-mic addition line G(?), selecting plants of 2n=42 in the F(?) hybrids derived from fussion (n-6B) female gamete and (n+G(?)) male gamete, and investigating the pairing of N-banded chromosomes at MI of PMC's in this F(?) hybrids, it was concluded that a satellited and highly heterochromatinized G genome chromosome (G(?)) belongs to the homoeologous group 6 as 6B does. So the chromosome G(?) can be designated as 6G. With same method, the homoeologous grouping of V genome chromosomes of H. villosa is going to be determined.