Development Of Wheat Near Isogenic Introgression Lines And Characterization Of Progenies Derived From Triticum Aestivum×Ae. Longissima

Wheat is one of the most important crops in the world, dissect the genetic base underlying theagronomy traits and broaden the genetic resources, improve the ability of wheat to various stress toimprove the yield and quality continuously, is a long-period task for us. In the backcrossing progeniesof an artificial synthesized hexaploid wheat Am3 by crossing Triticum carthlicum with Aegilopstauschii, introgression lines containing different donor parent chromosome fragment were selectedaided by molecular markers to prepare for the QTL location of agronomy import traits as well as finemapping and cloning of QTL. At the same time, in order to transfer the useful genes from Aegilopslongissima to wheat, progenies of Aegilops longissima Schw.et Musch (2n=14, S¹S¹) crossing withLaizhou953 were identified by cytology, GISH and SSR, the agronomy traits, resistance to podwderymildew and stripe rust were also scored. The results obtained were listed as below.1. In the BC4F2 progenies of Laizhou953 crossing with Am3, 97 single plants derived fromdifferent lines were selected to detect the introgressed donor fragment by SSR marker. Among the 610pairs of primers of that can amplify products in both of the parents, 205 pairs of them can detectpolymorphism, about 33.6% of the used primer pairs. Among them, 166 have been mapped in thewheat SSR consensus map, the other 39 pairs haven't been mapped or integrated in the consensus map.Detection by using the polymorphic markers in the 97 lines showed there were 106 markers appearedin at least one introgression line, account for 51.7% of the polymorphic markers. 15 of the 97 linesdetected no introgressison. There were 162 homozygote and 166 heterozygote fragments were detectedin the remained 82 lines, every line contained 0-9 homozygote fragment and 0-8 heterozygotefragments, averaged 1.98 and 2.02 homozygote and heterozygote fragment. 16 of the introgression linedetected one and 17 lines detected two introgression lines, the others contained 3 or more than threeintrogression fragments.2. According to the wheat consensus SSR map, size of the introgression fragment were estimatedand the ratio of the introgression fragments account for the wheat genome were calculated. The lengthof the introgression fragment ranged from 1.5cM to 62.5cM. The average length of the homozygotefragments was 15.4cM, while it was 12.29cM of the heterozygote fragments (except the unlocatedfragments). The donor genome fragments account for 0-6% of the receptor genome, averaged 1.31% inevery introgression line. In the 82 lines, the introgressed donor genome was 810.5cM, about 31.64% ofthe donor genome (except the unlocated markers). Among the 21 linkage groups, only the 4Dchromosome detected no introgression fragments, while the 2D chromosome detected mostintrogression, and 40 fragments were detected. The 6A and 4D chromosome detected leastintrogression. The introgressed donor chromosome of 2D, 3B, 6B and 1D were the longest, andcovered 59.8%, 59.5%, 59.1%, 59% of the chromosome, respectively. While the introgressed donorchromosome of 6A, 7D and 4D were the least, which covering 4.2%, 5.8%, 0% of the chromosome.According to the wheat SSR consensus map, the coverage map of the introgression of every chromosome was draw.3. Nine agronomy traits and salt tolerance at seedling stage of 140 BC₄F₃ were scored, most of thebackcrossing progenies were similar to the recurrent parent, the phenotype of the traits displayedcontinuous distribution. For every trait, there were plants showing apparent derivation from therecurrent parent, which were caused by the alien introgression. There were plants showing betteragronomy traits than the recurrent parent, which indicated that although the traits were inferior,favorable loci exist and can be introgressed into elite cultivar. Backcrossing can exhume useful genesfrom wild relative species of wheat and make use of them in wheat breeding. One-way ANOVAanalysis was used to detect QTL loci concern to nine agronomy traits using the data obtained in threeyears. 35, 33, 28(seven traits) QTL loci were detected in threes years, respectively. Part of the loci wasdetected in three years and part was detected in two years which indicated they were QTL lociexpressed stably. Detection of the QTLs made the foundation of fine mapping and cloning of the QTLs.4. An introgression containing the Xgwm113, WMC238, Xgwm513, CWM213 markers increaseplant height apparently. One-way ANOVA analysis also detect the loci, graphical analysis showed theloci was located near Xgwm113 and WMC238. Selfing progenies of a heterozygote of the locus wereused to map the locus. Other works were going on to map the detected loci. Development of the wheatintrogression lines represent a first step towards the assessment and utilization of genetic variation inexotic wheat which may promote the breeding progress, serve for the verification of QTLs and finemapping of QTLs as well as QTL map-based cloning.5. Aegilops longissima Schw.et Musch (2n=14, S¹S¹) is one of the potential donor of B genome ofwheat, and the donor of favorable genes for wheat improvement. In the BC₃F₅ generation, 6 singleplants with chromosome number 2n=44 and 8 single plants with chromosome number 2n=42 wereselected by cytology observation. Chromosome configuration analysis in pollen mother cells atmetaphaseâ… of meiosis indicated the chromosome configuration were stable, there were only bivalentsin part of the single plants and only seldom univalents and multivalents appeared in the others.Agronomy traits analysis showed the 14 selected lines showed apparent difference compared withLaizhou953. Resistance identification indicated the eleven selected lines 2479-1, 2484-2, 2492-1,2502-1, 2503-1, 2522-1, 2533-2, 2534-1, 2540-2, 2543-1, 2544-1 were high resistant to powderymildew. The five selected lines 2479-1,2480-1,2482-1,2484-2,2492-1 were high resistant to striperust.6. Ae. longissima genomic DNA was used as probe and Chinese spring genomic DNA was used asblocking to identify the selected lines by in situ hybridization. The results showed the five lines 2479-1,2480-1, 2534-1, 2538-1, 2540-1 with chromosome number 2n=44, all contained a pair of alienchromosomes, they were addition lines. 2544-1 contained two pairs of alien chromosomes and was asubstitution-addition line. 2484-2, 2502-1, 2503-, 2533-1, 2543-1 with chromosome number 2n=42 allcontained a pair of alien chromosomes, they were substitution lines. There were no alien geneticmaterials were detected in 2482-1, 2492-1.2522-1 was a translocation line. 7. 240 pairs of SSR primers were used to detect polymorphism between the two parentsLaizhou953 and Ae. longissima. There were 70 pairs of them can amplify stably and detectpolymorphism in Laizhou953 and Ae. longissima. They were used to identify the 14 lines and only 31of them appeared in them. The results indicated that 2540-2 may be a 6S¹ addition. 2502-1, 2503-1 maybe two 5S¹ (5A) substitution, 2533-2 may be a 6S¹ (6B) substitution, 2543-2 may be a substitutionconcern to 6S¹ and 4D. 2522-1 may be 2S¹S-6DS translocation line. There were no alien geneticmaterial detected in 2482-1 and 2492-1, but there were SSR markers showed alien Ae. longissimagenetic material introgressed into wheat.