Development And Characterization Of Triticum Aestivum-Hordeum Californicum Alien Chromosome Lines And Powdery Mildew Resistance Evaluation

Sequential chromosome C-banding/Fluorescence in situ hybridization (FISH) wasconducted on Root-tip cell (RTC) chromosomes of H. californicum and Triticum aestivumc.v. Chinese Spring-H. californicum amphiploid. The results showed that mostchromosomes of H. caIifornicum had strong terminal bands. Different chromosomes couldbe distinguished by their unique band pattern and could be identified in the wheatbackground. The FISH results using labeled 45SrDNA as probe revealed that there weretwo hybridized signals on a pair of H₇ chromosomes of H. californicum. Based on thechromosome C-banding and FISH results, karyotype analysis was conducted using Moticimages plus 2.0ML software. The karyotype formula of H. catifornicum was 2n=2x=10m(2SAT)+4sm.T. aestivum L. cv. Chinese spring (CS)-H.caIifornicum amphiploid was crossed to CS,then backcrossed and self-fertilized. Among the BC₂F₄ progenies, the genetic constitutionof backcross progenies were analyzed by morphology observation, sequentialC-banding/FISH on root tip cell chromosomes, configuration analysis of pollen mother cell(PMC) at MI, biochemical and molecular marker analysis. Three disomic addition(DA2H;DAH₁; DAH₄), three monosomic addition(MA5H; MAH₁; MAH₄), two telosomic addition(DtH₄, MtH₄) and one multiple addition lines were identified. Among them, all theH.californicum chromosomes except H5 were involved. STS-PCR and RFLP(Restrictedfragment length polymorphism) analysis using 2BL specific markers indicated that H3chromosome belongs to the wheat homoeologous group 2, and hence could be designatedas 2H. SDS-PAGE showed that H2 chromosome belongs to the wheat homoeologous group5, and hence could be designated as 5H. All the parent lines and the identified alienchromosome lines were evaluated for powdery mildew resistance. The CS-H.californicumamphiploid showed better powdery mildew resistance than CS. Addition lines DAH₁,MAH₁, DAH₄, MAn₄ and the multiple addition lines also showed good powdery mildewresistance, indicating that chromosomes H₁ and H4 might involve powdery mildew resistance of H.caIifronicum.The identified powdery mildew resistant addition lines shouldhave great potential value in wheat breeding for powdery mildew resistance.