In Situ Hybridization And Molecular Markers Identification Of Wheat-agropyron Cristatum Alien Translocation Lines

The kernel number per spike is the most important factor of the many potential characteristics that determine wheat yield. Agropyron cristatum (L.) Gaertn., a wild relative of wheat, is resist to abiotic stress, major diseases and has many high-yield characteristics, e.g. more tillers, more spikelets and more florets. Transfer the excellent gene(s) from A. cristatum to wheat, is an effective mothed to widen the wheat genetic background and improve the wheat yield. In this research, wheat-A. cristatum alien translocation lines induced by ionizing radiation and gametocidal chromosome were identified by GISH and molecular markers. The results are as following:1. Eighteen translocation lines were obtained in F3 of wheat-A. cristatum alien translocation lines induced by gametocidal chromosome and ten homozygous translocation lines in F3 and F4 were detected by GISH. There were two types of reciprocal translocation and one terminal translocation of M4 of irradiated hybrid seeds (4844-12/Gaocheng8901).2. The two-color GISH-FISH or twice hybridization of two color FISH-GISH showed that A. cristatum chromosome 6P could be translocated to wheat ABD genome, and the recombination frequency occurred with A and B genomes was higher than which with D genome. Wheat chromosomes involved in the eight translocaion lines were identified clearly, including 1A, 2A, 5A, 3B, 6B and 3D.3. We also obtained eighteen deletion lines with different length of chromosome 6P by GISH.4. Three P genome-specific SCAR markers and six 6P-specific STS markers were used to identify 82 M4 introgression lines with characteristics of more spikelets and more florets but no GISH signals. We selected fifty-two positive plants (63.41%). The positive frequency detected by SCAR markers (36 plants, 43.90%) was higher than STS markers (28 plants, 34.14%).5. Utilized the whole-arm translocation lines, partial of the STS markers were mapping on the chromosome 6P. The results identified 12 STS markers belong to the short or the long arm. Six of them were 6PS-specific markers, and others were 6PS-specific markers. Seven of them were identified more elaborate utilized the fragment translocation lines and deletion lines.6. The translocation (introgression) lines induced by irradiate had the better agronomic features. The kernel number per spike of 19 introgression lines (23.17%) exceeds 100. These lines could be utilizaed directly in the wheat inprovement.7. Fourteen wheat-A. cristatum 2P translocation lines were detected in F2 progeny, and the frequency of translocation was 5.34%, including 6 plants of whole-arm translocation, 1 plant of large fragment translocation, 3 plants of terminal translocation, 2 plants of intercalary translocation and 2 plants of dicentric translocation.The wheat-A. cristaum 6P translocation, deletion and introgression lines obtained in this study had provided novel material for genetic improvement of kernels number per spike and basic researches of wheat. The development and location of the 6P-specific markers will be useful of tracing quickly and identifying the 6P chromatin in wheat background, which laid the foundation for constructing the physical map of 6P chromosome and locating and cloning the multi-kernel gene(s).