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Development and characterisation of structural changes in chromosome 3Hᶜʰ from Hordeum chilense in common wheat and their use in physical mapping

Said, Mahmoud, Recio, Rocío, Cabrera, Adoración
Euphytica 2012 v.188 no.3 pp. 429-440
Aegilops cylindrica, DNA probes, Hordeum chilense, barley, chromosome translocation, fluorescence in situ hybridization, genetic markers, hybrids, loci, progeny, repetitive sequences, wheat
Structural changes in Hordeum chilense chromosome 3Hᶜʰ were obtained in common wheat background by crossing tritordeum (the fertile amphiploid H. chilense–T. turgidum, 2n = 6x = 42, AABBHᶜʰHᶜʰ) with the disomic addition line of chromosome 2Cᶜ from Aegilops cylindrica in common wheat cv. ‘Chinese Spring’ (CS). Hybrid plants (2n = 43, AABBDHᶜʰ + 2Cᶜ) monosomic for the gametocidal chromosome were crossed with common wheat both CS and Anza. Rearranged 3Hᶜʰ chromosomes were identified and cytologically characterized by FISH using both pAs1 repetitive sequence and genomic H. chilense DNA as probes. Two deletions on the short and long arm respectively, (del3HᶜʰS and del3HᶜʰL) and two reciprocal centromeric translocations involving chromosome 3Hᶜʰ and 3D were identified. The breakpoints (FL) in the deleted chromosomes were determined as 56 % in del3HᶜʰS and 42 % in del3HᶜʰL, respectively. In order to obtain homozygous plants for rearranged 3Hᶜʰ chromosomes the derived progenies were self-pollinated for four generations and the following lines were established: (1) disomic substitution DS-del3HᶜʰS(3D) (2n = 42) in CS; (2) disomic addition DA-del3HᶜʰL (2n = 44) in Anza; (3) homozygous translocation T3HᶜʰS·3DL (2n = 42) in CS, and (4) homozygous translocation T3DS·3HᶜʰL (2n = 42) in CS. These four lines were morphologically and agronomically characterized under field conditions. All lines were fertile, stable and vigorous. The four lines obtained were used to develop specific DNA markers for chromosome 3Hᶜʰ in wheat. We studied the applicability of 162 barley chromosome 3H primers (55 genomic-SSRs, 17 genomic-STSs, 66 EST-SSRs and 24 EST-SNPs) to amplify markers showing polymorphism between H. chilense and common wheat. A total of 53 (32.7 %) markers gave reliable amplifications in H. chilense and among them 31 (19.1 %) were polymorphic between H. chilense and CS and Anza. Eighteen of the 31 polymorphic loci were mapped onto different chromosome sub-arm regions of chromosome 3Hᶜʰ. Arm locations of these markers on barley chromosome 3H were determined using wheat–barley ditelosomic lines for 3HS and 3HL arms. The comparative positions of these markers in H. chilense and H. vulgare are discussed.