C-banding pattern and polymorphism of Aegilops caudata and chromosomal constitutions of the amphiploid T. aestivum — Ae. caudata and six derived chromosome addition lines

Abstract

C-banding patterns were analysed in 19 different accessions of Aegilops caudata (= Ae. markgrafii, = Triticum dichasians) (2n = 14, genomically CC) from Turkey, Greece and the USSR, and a generalized C-banded karyotype was established. Chromosome specific C-bands are present in all C-genome chromosomes, allowing the identification of each of the seven chromosome pairs. While only minor variations in the C-banding pattern was observed within the accessions, a large amount of polymorphic variation was found between different accessions. C-banding analysis was carried out to identify Ae. caudata chromosomes in the amphiploid Triticum aestivum cv 'Alcedo' - Ae. caudata and in six derived chromosome addition lines. The results show that the amphiploid carries the complete Ae. Caudate chromosome complement and that the addition lines I, II, III, IV, V and VIII carry the Ae. caudata chromosome pairs B, C, D, F, E and G, respectively. One of the two SAT chromosome pairs (A) is missing from the set. C-banding patterns of the added Ae. caudata chromosomes are identical to those present in the ancestor species, indicating that these chromosomes are not structurally rearranged. The results are discussed with respect to the homoeologous relationships of the Ae. caudata chromosomes.

No Neocentric Activity on <i>Aegilops markgrafii</i> Chromosome E

“…markgrafii chromosomes, only chromosome E shows a morphologically stretched domain during MI and AI when present as a univalent. Chromosome E, in distal position of the long arm, contains N-and Cbanding positive heterochromatin [Schubert et al, 1987;Friebe et al, 1992]. It can not be decided, however, whether this heterochromatin or interspersed euchromatin is responsible for the stretched domain and whether it is always the same site inside or around the constriction ( fig.…”

“…The presence of neocentromeres on different chromosomes and their activation after interspecific crossings only during meiosis support the idea that heterochromatic regions are often the result of selection by meiotic drive. However, due to fre- markgrafii chromosome E and all wheat chromosomes (translocation chromosome 3BS·6BS is shown as an example and identified via its structure according to Friebe et al [1992]) contain CENH3 only at the primary constriction.…”

“…markgrafii domain on different homoeologous groups also does not indicate the presence of neocentric activity on Ae. markgrafii chromosome E. Schubert et al, 1987] and C-banding [according to Friebe et al, 1992] pattern of Ae. markgrafii (accession S740-69) chromosome E. No elongated chromatin segments are detectable at the long arm.…”

Molecular and Cytogenetic Characterization of a Powdery Mildew-Resistant Wheat-<b><i>Aegilops mutica</i></b> Partial Amphiploid and Addition Line

“…Among the wild relatives, the standard karyotype of many species has been established, such as Thinopyrum intermedium [Friebe et al, 1992a], Ae. caudata [Friebe et al, 1992b], Ae. umbellulata [Friebe et al, 1995a], Ae.…”

C-banded karyotype of Thinopyrum bessarabicum and identification of its chromosomes in wheat background

“…Squarrosa auct. non L.) (Friebe et al 1992a), C genome chromosomes of Aegilops markgrafii (Greuter) Hammer (Friebe et al 1992b), R genome chromosomes of rye, Secale cereale L. (Mukai et al 1992), and S 1 genome of Ae. longissima Schweinf.…”