The Effect Analysis Of Different Methods To Induce T.aestivum L.-Th.intermedium Translocation Lines With Resistance To Powdery Mildew

T. aestivum L.–Th. intermedium alien disomic addition lines resistant to powdery mildew was derived from crossing between Triticum aestivum L (Yannong 15) and Thinopyrum intermedium. This study was to create translocation lines with the alien addition lines using such method as homoeologous chromosome pairing, in vitro culture and gametocidal chromosome-induced aberration. In the same time, the effectivity of the three methods was compared. The following was the main results. 1. The crossing of T. aestivum L.–Th. Intermedium alien disomic addition lines and Nonglin26 with two gametocidal chromosome 3C(from Ae. triuncialis) was carried out to study the cytogenetic character of the progenies, combining with identification of powdery mildew resistance. Several results were concluded: (1) The chromosome configuration of F₁ PMC MI was disorder; Chromosome fragments were found in 39.48% cell; Lagging and bridge of chromosomes were observed at anaphase; Considerable micronuclei (48.65%) were formed in tetrads. These phenomena were mainly caused by the gametocidal chromosome, which can induce chromosome structural aberration such as breakage effectively. (2) Plants resistant to powdery mildew F₂ were not stable in respect of cytological character: The chromosome number varied from 41 to 44; Univalents,multivalents,lagging chromosomes and bridge of chromosomes appeared universely.(3) In F₃, though the chromsome number and powdery mildew resistance were still discrete, the chromosome configuration was more stable than that in F2, the RCC of F₃ droped also. Several plants with 42-chromosome number that were immune to powdery mildew were selected from F₄ generation, but they still needed further identification. 2. The CS-5B nullisomy was used to cross with T. aestivum L.–Th. intermedium alien disomic addition lines resistant to powdery mildew. The cytogenetic character of the progenies was studied, combining with identification of powdery mildew resistance. The resuts were concluded: In F₁, there were many univalents and multivalents in PMC MI, showing that CS 5B nullisomy could promote partial homoelogous pairing effectively; In F2, the chromosome number of resistant plants segregated and PMC MI chromosome configuration was disorder. But the number of univalent and RCC fell compared with that in F1. Five plants resistant to powdery mildew were chosed from F3 and their PMC MI chromosome configuration was comparatively more stable, which probably were the special materials that included powdery mildew resistance gene from Thinopyrum intermedium. However, they still needed further identification. 3.An efficient plant regeneration system was developed from the immature embryos of Triticum aestivum L.-Thinopyrum intermedium alien disomic addition lines, which was resistant to powdery mildew. The protocol was based on a series of experiments involving the callus induction and differeentiation. The experiment studied the effects of embryos size ,exogenous hormones and desiccation treatment on callus induction and differentiation of the immature embryos. Immature embryos (0.8–1.5 mm) showed high ability to produce embryogenic callus capable of regenerating green plants; The medium Murashige and Skoog's (MS) added with 2mg/L 2, 4-D and 0.5mg/L NAA gave the best embryogenic callus induction and the embryogenic callus maintained high regeneration capacity in the basic medium adding 1mg/L 2, 4-D,0.5mg/L NAA and 0.25mg/L KT; The suitable differentiation medium used was MS added with 0.5mg/L KT, 0.5mg/L NAA and 100mg/L adenylic acid. Suitable time of partial desiccation (6-12h) could improve the regeneration capacity of the callus cultured for 3-4 month effectively. Bud green spot and root green spot were observed during the differentiation of callus and the difference between them was described. Regenerated shoots were rooted on half-strength MS medium containing 0.2 mg/L NAA. Plants were successfully transferred to soil and grew well. This efficient plant regeneration system of Triticum aestivum L. -Thinopyrum intermedium alien disomic addition lines provided a foundation for the study of somaclonal variation and selection of translocation lines. 4.The examination of the chromosome in regenerated plants indicated that the chromosome number variation is remarkable. The plants maintaining 2n=44 were only 40.38% of the total regenerated plants and the plants with the...