Molecular Cytogenetic Characteristics Of Wheat-Thinopyrum Intermedium Addition Line 14-569

Common wheat (Triticum aestivum L.,2n=42), is one of the most important food crops and its yield and quality affect the daily life of peoplein the world. Due to the long-term use of a few elite germplasm resources in wheat breeding, genetic basis of common wheat has become tends to be narrow, genetic diversity wheat was also reduced. All those reulted in the loss of resistance and the reduction of adaptability for enverriment. and limiting the improvement of yield and quality of wheat. It is an effective way to solve this problem by wide hybridization between wheat and its relative species to transfer excellent genes into common wheat. Thinopyrum intermedium (2n= 42) is a tertiary gene pool of wheat, with many excellent characteristics for wheat improvement. Th. intermedium is easy crossed with wheat. Therefore this species can provide excellent alien genes for wheat breeding.A stable wheat line 14-569 was studied in this research which was derived from the progeny between Chuan Mai 107 (CM 107) and wheat-Thinopyrum intermedium partial amphiploid TAI7045. The evaluation of agricultural traits, cytological observation, in situ hybridization and PLUG marker analysis of line 14-569 were carried out. The results are as follows:1. The results of agricultural traits between line 13-337 and its recurrent parent CM107 indicated that line 14-569 is resistant to stripe rust, plant type is tight, effective tiller number, spike length, spikelet numbers per spike, and 1000-grain weight characters are obviously better than Chuanmai107. The twin spikelets emerged in the lower middle position of the spike in line 14-569. The kernel trait of line 14-569 is similar to chuanmai107 but the kernel of line 14-569 is plumper.2 The root tip cells of line 14-569 have a chromosome number of 2n=44 by cytological observation. This result suggests that 14-569 might be an addition line. We examined the chromosome pairing behavior of line 14-569 in the pollen mother cells (PMCs) during metaphase I,22 bivalents were found in almost PMCs and few univalent exist, which demonstrates that the line 14-569 is basically cytogenetical stable.3 Genomic in situ hybridization (GISH) using Th. intermedium genomic DNA as probe combined with fluorescence in situ hybridization (FISH) indicated that the line 14-569 contained one pair chromosomes of Th.intermedium. GISH using rye and Th.intermedium genomic DNA as probes respectively showed there is a pair of 1BL.1RS translocation in line 14-569. GISH using Pseudoroegneria spicata as a probe further identified the pair of chromosome of Th.intermedium in line 14-569 and found the pair chromsomes belongs to St genome. Those results demonstrated that line 14-569 is an alien disomic addition lineand includes a pair of 1BL.1RS translocation chromosome, and added chromosomes belong to St genome.4. PLUG molecular marker detected found that two pairs of primers TNAC1627 and TNAC1648 located on the third homology group amplified the same specific band of 1100bp and 400bp, respectively, among line 14-569 and Th. intermediate or Ps. Spicata, and no same bands were amplified in common wheat. Combining with the results of GISH previously, we can infer line 14-569 was added a pair of 3St chromosomes of Th. intermediate.5. Using Oligo-pSc119.2-1 (green) and Oligo-pTa535-1 (red) as probe, the analysis of the mitotic chromosomes structure of different plants of 14-569were carried out, the results indicated that the structures of some chromosomes of line 14-569have changed. Compared with Chuanmai 107 chromsomes, these changes can be reflected in the following aspects:5AL carried intercalary strong green signal of Oligo-pSc119.2-1 and red signal of Oligo-pTa535-1. A short arm of chromosome 5B in its position near the centromere was broken; the satellite of chromosomes 6B was lost; and there is no green signal of Oligo-pSc119.2-1 on the terminal of short arm of chromosome 3D. Experimental research suggests that the Chromosomal Structural Variation in 5A and 3D chromosomes basically exist in all the plants of the line 14-569. The breakage in 5B chromosome and the loss of satellite of 6B chromosome only exist in a few plants.