Studies On Molecular Cytology Genetics Of The Progenies Derived From Combination Of Hybrid Between Wheat And Octoploid Agroticum With Radiation

Agropyrum carries fruitfully valuable genes for wheat genetic improvement, for example the resistance of rusts, powdery mildew, BYDV, drought and cold tolerance, high protein content, etc. By distant hybridization we can transfer the chromosome's fragments or genes into wheat, making the latter obtain some fine properties of the related species.In this research, the hybrid F₁ from the cross between an Octoploid Tritielytrigia types derived from wheat- Ag. intermedium and and a Octoploid Tritielytrigia types derived from Elytrigia elongatum (10X) was used as male, to transfer desirable genes of Agropyrum into the wheat variety, Chuanmai 107, recently released in southwest China. The seeds of F2 generation were γ-radiation treated with 4000 roentgen.From the hybrid progenies of Octoploid Tritielytrigia type's×wheat, some translocations with desirable genes might be selected. In addition, more than 10 wheat-Agropyrum alien addition lines have been obtained preliminarily cytological identification. In present studies, we characterized these new wheat lines with resistance gene on Karyotype, chromosome pairing of PMC, Genome in situ hybridization. The results were as follows:1. Analysis of resistance geneIn F₂M₆, many wheat plants showed high resistance to powdery mildew, even completely immunity. For example, 12-3, 30-1, 37-2, 37-3, 37-4 and most plants of serics 3 progenies expressed completely immunity to powdery mildew. But common wheat 89-107 exhibited high or middle susceptivity to powdery mildew. These suggested that the high powdery mildew-resistance in Octoploid Tritielytrigia types had probably been transferred into common wheat 89-107.2. Analysis of chromosome pairing of PMC MIThe chromosomal behavior at meiosis in pollen mother cells of 148 plants from F₂M₆ progeny was observed. Results indicated that the chromosome number of observed plants ranged from 2n=41 to 2n=46, of which the plants of 2n=42 are the more frequent. Most of plants with 2n=42 have stable cytology characteristics, however, trivalents, and other multivalents were also recorded at MI in other plants with 2n=42, suggesting the translocations with desirable genes might be selected from these plant progenies. Inaddition, more than 10 wheat- Agropyrum alien addition lines have been obtained preliminarily cytological identification. 3. Genome in situ hybridizationThe results of GISH with genomic DNA of Ps. sirigosa as the probe and Chinese Spring as the blocking proved that the line 02-97 was a disomic substitution lines with a pair of E. Agropyrum chromosomes; the lines, 26-l(2n=44), 27-l(2n=44) are alien disomic addition lines with a pair of E. Agropyrum chromosomes in wheat background; the line 31-4 (2rr= 43) was a addition line with a St-chromosome derived from Ag. intermedium chromosomes.