Influence of chromosome structure on the degree of meiotic pairing of intercultivar wheat hybrids (Triticum aestivum L.)

Vega, Carlos García de la; Fominaya, A.; Ferrer, Esther

doi:10.1038/hdy.1987.63

Cited by 5 publications

(3 citation statements)

References 20 publications

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“…variabilis v. lypica, 25.30 (Cuñado, 1992). This behaviour is similar to that of intervarietal hybrids of common wheat, Triticum aestivum (Waranabe, 1962;Dvorak & McGuire, 1981;Vega et at., 1987). This decrease in association frequency (hybrid desynapsis) cannot be attributed to structural changes since multivalents are not observed (Table 1).…”

Section: Discussionmentioning

confidence: 50%

Genomic analysis in the genus Aegilops. II. Interspecific hybrids between polyploid species sharing two common genomes

Cuñado

1993

Heredity

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Hybrids between polyploid Aegilops species sharing two common genomes were analysed at metaphase I by using a C-banding technique in order to establish genome relationships. In all cases it allowed discrimination between associations of chromosomes with similar morphology and C-banding belonging to the same genomes (homomorphic associations) and associations involving different chromosomes (heteromorphic associations). In the hybrids involving Ac. variabilis and Ae. kotschyi, (UUSS), it was also possible to identify the U and S genomes, which are shared by the tetraploid species, and their analysis indicated that the genomes of both species are essentially unaltered. However, the data of the Ae. crassa(6x) XAe. vavilovii (DDDMMN) hybrid showed that the divergences between the shared genomes are at present substantial despite their common origin. By contrast, in the case of the Ae. triaristata(6x) X Ae. triaristata(4x) (UUMMN) hybrid the data did not confirm that the hexaploid species arose from the tetraploid one.

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Section: Discussionmentioning

confidence: 50%

Genomic analysis in the genus Aegilops. II. Interspecific hybrids between polyploid species sharing two common genomes

Cuñado

1993

Heredity

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“…The recovery of higher pairing in the hybrid of SC x CD-7 than in the CD-7 parent also supports this hypothesis. However, the possibilities of cryptic structural hybridity (VEGA et al 1987) and molecular differentiation (DVORAK and MCGUIRE 198 l), presumably as a result of isolation, cannot be ruled out since the hybrids between the landraces, as a whole, showed lower univalent frequency than did their counterpart hybrids with SC.…”

Section: Discussionmentioning

confidence: 99%

Cytogenetic Studies in Ethiopian Landraces of Tetraploid Wheat (Tviticum Turgidum L.). II. Spontaneous Chromosome Translocations and Fertility

Belay

Merker

2004

Hereditas

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Belay, G. and Merker, A. 1997. Cytogenetic studies in Ethiopian landraces of tetraploid wheat (Triticum turgidurn L.). 11. Spontaneous chromosome translocations and fertility. -Hereditas 126: 35-43. Lund, Sweden.Meiosis was studied in seven tetraploid (2n = 4x = 28) wheat (Triticum turgidum L.) landrace morphotypes of Ethiopian origin and one introduced durum variety, 'Boohai'. The objectives were to detect the presence of chromosome structural rearrangements by using the variety 'Senatore Cappelli' (SC) as a reference and to investigate if the previously reported low fertility (seed set) of the landraces has a chromosomal basis. All the parents exhibited a normal bivalent pairing at metaphase I (MI) except one (CD-7) that showed a relatively high proportion of pollen mother cells (PMC) with univalents (0.40/PMC). 'Boohai' and two of the landraces from Ambo district were structurally similar to SC. The remaining five landraces each differed by one translocation from SC. These, in turn, differed from each other by one or two translocations while two of the landraces carried the same translocation. However, in some of the landrace x landrace hybrids there was a tendency of restricting the formation of more than one quadrivalent per PMC. Four different translocations involving four to six chromosomes are present in the material studied. Lack of pairing, as measured by univalent frequency, vaned for the different F, hybrids. Generally, however, it was lower in the F, hybrids between the landraces than in hybrids between the landraces and SC. In almost all cases, division stages following MI proceeded as normal. Inversions were absent or too small to be detected. Meiotic irregularities have little to do with the low fertility of most of the parental landraces. In the F, hybrids, on the other hand, high univalent frequency and multivalent associations impaired seed set depending upon the cross combination. The results indicate that chromosome structural polymorphism for translocations may be common in Ethiopian tetraploid wheat landraces that might have played a role in maintaining their diversity by producing new linkage relationships. From breeding perspective, the bulk selection method and/or backcrossing to high fertility genotypes seem to be appropriate when these landraces are employed in hybridisation programmes.

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“…Such information could help with deciding which recombination products are most likely to be useful. Chromosome structural differences that are encountered may be the result of evolutionary divergence of the alien and corresponding common wheat chromosome regions [14]; may be introduced through the involvement of the Chinese Spring homoeologous pairing locus deletion line (CSph1b) which is chromosomally unstable [15]; or it may be due to natural karyotype variation within wheat itself [16][17][18]. This study aimed, firstly, to confirm the presence of a height reducing gene (here designated H) on the Lr54/Yr37 translocation.…”

Section: Introductionmentioning

confidence: 99%

Derivation and Characterization of Recombinants of the Lr54/Yr37 Translocation in Common Wheat

Heyns¹,

Pretorius²,

Marais³

2010

TOPSJ

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The wild relatives are an important source of new genes for the genetic improvement of wheat. Leaf and stripe rust resistance genes Lr54 and Yr37 occur on an Aegilops kotschyi-derived chromosomal translocation that had apparently replaced wheat chromosome arm 2DL. The alien chromatin also includes the locus of a gene for reduced plant height (H), which appears to be different from Rht8 on chromosome arm 2DS. The introgressed genes were mapped relative to homoeologous wheat marker loci following the induction of chromosome pairing in translocation heterozygotes that lacked the Ph1 locus. Ten recombined Lr54/Yr37 translocation chromosomes were derived and characterized with microsatellite, AFLP and SCAR markers. The data suggested that there was significant homoeology between the full-length translocated segment and the wheat 2DL chromosome arm. The recombined translocations apparently resulted from single crossovers during which the distal end of the long arm of the translocation chromosome was replaced with wheat chromatin. Recombinant (Lr54/Yr37-74) retained the least alien chromatin and both resistance genes, yet had lost the reduced plant height gene. A polymorphic AFLP fragment was converted into a dominant SCAR marker to detect rec. #74. In addition three wheat microsatellite loci that map to the introgressed region provide a useful recessive marker system to detect Lr54/Yr37. The shortened translocation could be useful in breeding and may be used for continued, closer mapping of the resistance genes.

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Influence of chromosome structure on the degree of meiotic pairing of intercultivar wheat hybrids (Triticum aestivum L.)

Cited by 5 publications

References 20 publications

Genomic analysis in the genus Aegilops. II. Interspecific hybrids between polyploid species sharing two common genomes

Genomic analysis in the genus Aegilops. II. Interspecific hybrids between polyploid species sharing two common genomes

Cytogenetic Studies in Ethiopian Landraces of Tetraploid Wheat (Tviticum Turgidum L.). II. Spontaneous Chromosome Translocations and Fertility

Derivation and Characterization of Recombinants of the Lr54/Yr37 Translocation in Common Wheat

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