Development And Identification Of Hybrid Offsprings Between Wheat And Thinopyrum Intermedium

Thinopyrum intermedium (Host) B.D (2n=6X=42,E1E1E2E2StSt), one of excellent species in Elytrigia of Triticeae, has many excellent characteristics, such as vigorous root system, cold resistance, tolerance to stress environment, big spike and multi-spikelet. It is easy to cross with wheat, therefore, many desirable genes of Th. Intermedium had been transferred into wheat through wide hyridizatiom between common wheat and Th. intermedium. In this research,Th.Intermedium was crossed with common wheat variety "Chuanmai-107" which was developed by Sichuan Academy of Agricultural Science at the end of 1990s. The hybrids were backcrossed with Chuanmai-107 twice, and then selected continuously to BC2F10, when we got 10 lines with special traits.And these lines were identified by morphology, cytology, GISH and SDS-PAGE. The main results were showed as follows:1. Cytological analysisChromosome numbers of lines 728,744,757,766,767 and 823 were 2n=44, and chromosome numbers of lines 738,793 and 763 were 2n=42, chromosome number of line 824 was ranged from 42 to 44. The chromosome pairing analyses of pollen mother cells showed that no trivalent and multivalent were found in lines 728,738,757,763, 766 and 767, and the average number of univalent in these lines were less than 0.4, and all the Relative Chaotic Coefficient were less than 0.02, suggesting that these 6 lines might be cytologically stable. However, more than 0.4 univalent on average and small amount of trivalent and multivalent were found in lines 744,759,823and 824, which suggested that these lines were not cytologically stable.2. Agronomy characteristics analysisSome morphological traits of 728,744,757,766,767,823 and 824 were similar to Th. intermedium, such as small leaf and stem which belong to second homologous group of wheat, These results inferred that chromosomes from the second homology group of Th. intermedium had been transferred into common wheat in these lines, while morphological traits of 738,759 and 763 were similar to that of common wheat Chuanmai-107. In addition, line 757 was immune to both powdery mildew and stripe rust, line 759 and 763 were resistant to powdery mildew, and line 728 and 767 were resistant to stripe rust and line 738 possessed short stem and more spikelets characteristics and was susceptible to both powdery mildew and stripe rust. However, the charcter segregation, such as plant height, tiller numbers, found in line 824 due to the cytological unstability. These results suggested that many characres of Th. intermedium might be transferred into common wheat.3. GISH analysisGISH was carried out using the genomic DNA of Th. intermedium as probe and the genomic DNA of Triticum aestivum var.'Chinese Spring'as block. The results showed that line 728,744,757,766,767,823 were substitution-addition lines of common wheat-Th.intermedium, of which 2 chromosomes of common wheat were substituted by 2 chromosomes of Th. intermedium and 2 chromosomes of Th. intermedium were added, because 4 chromosomes were found to be dyed into yellowish green under fluorescence microscope. Line 759 and 763 were substitution lines of common wheat-Th. intermedium. A small fragment of one chromosome of Th. intermedium was translocated to the end of one chromosome pair of wheat in line 738.4. SDS-PAGE of HMW-GSHigh molecular weight glutenin subunit composition of aboved materials were analyzed by sodium dodecy I sulphate polyacrylanide gel electrophoresis(SDS-PAGE). Chinese Spring (subunits:null,7+8 and 2+12),'Chuanmai-107'(subunits:null,7+8 and 2+12) and Th.intermedium were used as controls. The results indicated that the HMW-GS composition of line 728,738,757,766 and 767 were the same and showed to be 1,? and 5+10. The band "?" were located between "7" and "8". Line 759 and 763 were not stable on the aspect of HMW-GS composition. Because there were no specific bands of Th. intermedium, these results suggested that none of the frist homology group of Th.intermedium had been transferred into these lines.As conclusion, lines 728,744,757,766,767 and 823 were common wheat-Th. intermedium substitution-addition line with the trait of high-tillering, and most of these lines, except line 744 and 823, were stable. Line 728 and 767 were resistant to stripe rust, and line 757 was immune to both powdery mildew and stripe rust. The chromosome number of 824 was changing, and it was necessary to further selected. The segregation of both powdery mildew and stripe rust resistances in line 759 and 763, two common wheat-Th. intermedium substitution line were observed. Line 738 was a small fragment translocation line of common wheat and Th. intermedium, and it might carry those genes which controlled stem length and the number of spikelets. We can not certain that which chromosomes had been transferred into these lines unless we idendify them by Giemsa-C banding and molecular markers in the future.