Identification Of Hybrid Offsprings Between Wheat And Thinopyrum Intermedium

Thinopyrum intermedium (2n=42), one of the wild relative species of wheat, which has many excellent characteristics, such as multiflowers, multiseeds, good reproducibility, wide adaptability, cold and drought resistance, salinity tolerance, is a good genetic material for stress environment resistance and yield increasing in the wheat.genetic improvement.In this research,6wheat lines with special traits that derived from the progenies of hybrid between Th.Intermedium and common wheat variety,"Chuanmai-107" were studied."Chuanmai-107" was developed by Sichuan Academy of Agricultural Science at the end of1990s, and6wheat lines were derived the hybrid ten’s progenies between Th. intermedium and common wheat variety,"Chuanmai-107",,and then backcrossed with "Chuanmai-107" twice and selected.6wheat lines were identified by Agronomy characteristics and disease resistance, root tips chromosome count, chromosome pairing analysis at metaphase I of pollen mother cells of meiosis and genome in situ hybridization. The main results were showed as follows:1. chromosome numbers of lines10-840,10-841,10-842,10-844and10-845were2n=42.which appeared relatively stable by counting the numbers of root tips chromosomes and chromosome pairings at MI of pollen mother cells, while chromosome number of line10-843was ranged from42to44, trivalents and quadrivalents in some PMC’s in2n=44plant were observed.There were a lot of micronucleus found in the tetra spore of pollen mother cells of line10-845showing abnormal segregation, which might related to chromosome structural variation that caused by a Thinopyrum intermedium. Analysis of meiosis of6lines showed that no multivalent was found in lines10-840,10-841and10-844. And the average univalent number in these lines were less than0.4, and all the Relative Chaotic Coefficient were less than0.02, suggesting that these3lines might be cytologically stable. But the average number of univalent in lines10-842and10-845were more than0.4, which indicated that these2lines were unstable.cytologically2. Agronomic characteristics results indicated the line10-844had smaller stem, slender leaves and the appearance was similar to Th. intermedium, but the seed traits were between Th. intermedium and" Chuanmai-107", suggesting that the lines might be involved the second homoeologous group chromosome of Th. intermedium. In addition, the agronomic characteristics of lines10-840,10-841,10-842,10-843,10-845were similar to "Chuanmai-107", and there also were some special traits compared with parents:such as thicker stem, more grain. All materials found in the field are resistance to powdery mildew, and part of lines were found the stripe rust resistance is segregation, thus the powdery mildew resistance from Th.intermedium might be transferred to common wheat. However, the origin of stripe rust resistance gene was not known and it needed further studied.3. There were two complete chromosomes containing hybridization signals in lines10-840,10-841,10-845using GISH technology, and based on the chromosome pairing results of meiosis, indicating that the3lines might be disomic substituted by2chromosomes of Th.intermedium. There was only one complete chromosome containing hybridization signals in lines10-842and the plants of line10-843which chromosome number was2n=42. The2lines might be monosomic substitution. Line10-844was translocation lines with fragments transferred from Th.intermedium, suggesting that the changes of agronomy characteristics in these lines might be resulted from the transfer of Th.intermedium chromosomes.As conclusion, lines10-840,10-841,10-842,10-843and10-845were substitution lines between common wheat-Th. intermedium chromosomes, these lines have not only the resistance for powdery mildew, but also many agronomic characteristics showed differences compared wheat parent in tiller numbers, plant height, flag leaf area, spike length, spikelet numbers per spike, kernel number of per spike and so on..These variation agronomic characteristics provided genetic basis for further application. Chromosome numbers of line10-843were2n=42and2n=44, which needed to be further selected, and the stale substitution or addition lines might be obtained from10-843. All the materials were resistance to powdery mildew, indicating that the transferred chromosome from Th. intermium might carry powdery mildew resistance genes. Part of single plants were resistance to stripe rust in these studied material except line10-843, demonstrated that stripe rust resistance genes exist separation, which needs further selfing and selection to validate the fact and the origin of stripe rust resistance genes. Based on present results, these material are chromosome substitution and translocation, however, which chromosomes transferred from Th. intermium into these lines was not sure. This question might be further study by Giemsa-C banding and molecular markers in the future.