Wheat Chromosomes Of Group Research Articles

Substitution of Hordeum marinum ssp. gussoneanum chromosome 7HL into wheat homoeologous group-7

Ditelosomic (Dt) 7HLmar(7D) and monotelosomic (Mt) 7HLmar(7A) and 7HLmar(7B) wheat–barley substitution lines were developed by crossing monosomic 7A, 7B and 7D lines of common wheat cv. Saratovskaya 29 with disomic wheat–barley addition lines (2n = 44) that carry telocentric chromosomes 7HLmar from Hordeummarinum ssp. gussoneanum 4×. Genomic in situ hybridisation confirmed the presence of barley chromosomes in the wheat genome. The compensating ability of the telosome in each combination was assessed by its transmission rate to progenies of plants with 2n = 41 + t chromosomes. Seed set and transmission rates of the telosome depended on the identity of the competing wheat homoeologue. Of the three chromosomes wheat, the telosome 7HLmar compensated better for chromosome 7D and poorly for 7B. These and other data are discussed with respect to the phylogenetic relationships between the wheat chromosomes of group 7 and the chromosome of H.marinum, and the practical utility of these lines for wheat improvement is evaluated.

The homoeologous relationships of rye chromosomes 4R and 7R with wheat chromosomes

SUMMARYBy means of rye chromosome CR from Imperial added to Chinese Spring wheat the alien substitutions 4A/CR, 4A/CRS, 4B/CR, 4D/CR, 4D/CRS, 7A/CRL, 7B/CR, 7B/CRL, 7D/CR and 7D/CRLwere isolated. Substitutions 4A/CRSand 4D/CRShad a better fertility and vegetative vigour than the corresponding substitutions with the complete chromosome CR. In substitutions the entire chromosome CR did not compensate for the absence of wheat chromosomes of group 7, whereas the substitutions 7A/CRL, 7B/CRLand 7D/CRLwere more fertile than the corresponding nullisomics 7A, 7B and 7D. It was shown that the short arm of CR is homoeologous to wheat telosomes 4Aα, 4BLand 4DS, whereas most of the long arm of CR is homoeologous to the wheat arms 7AS, 7BSand 7DS. Rye chromosome CR is designated 4R. Only three substitutions with rye chromosome DR were produced. The fertility of substitutions 7A/DR and 7B/DR were considerably lower than that of nulli-7A and nulli-7B. The 4B/DR substitution was sterile. Rye chromosome DR is believed to be a double interchanged chromosome in comparison to the correspondingSecale montanumchromosomes. Rye chromosome DR is designated 7R. On the basis of substitution ability of CR and DR and several homoeologous gene loci on these chromosomes an evolutionary scheme for the derivation of theSecale cerealegenome fromSecale montanumis outlined.

MEIOTIC PAIRING BETWEEN SINGLE CHROMOSOMES OF DIPLOID AGROPYRON ELONGATUM AND DECAPLOID A. ELONGATUM IN TRITICUM AESTIVUM

It is shown that meiotic pairing between single chromosomes of closely related taxa can be studied in hybrids between alien addition and substitution lines. Using this technique, two chromosomes of diploid A. elongatum which appear to be homoeologous with wheat chromosomes of groups 6 and 7 were shown to pair with chromosomes of decaploid A. elongatum which are also homoeologous with wheat chromosomes of groups 6 and 7. Hence, pairing of these chromosomes verified the suggested homoeology among these chromosomes.Meiotic pairing was also studied in 2 hybrid progenies which carried specific telosomes of diploid A. elongatum in addition to a set of 7 Agropyron chromosomes which came from decaploid A. elongatum. The telosomes paired with the decaploid A. elongatum chromosomes in these hybrids. Hence, four chromosomes of diploid A. elongatum were shown to pair in common wheat with chromosomes of decaploid A. elongatum. Since pairing between diploid A. elongatum and decaploid A. elongatum chromosomes was generally low, it is suggested that the chromosomes assigned to the same group are not homologous but rather closely homoeologous.