Cytological analysis of hybrids among triticales and trigopiros

Abstract

We studied three different tricepiros: (Don Santiago x Don Noé), (Cumé x Horovitz) and (Cumé x Don Noé). The tricepiro (Don Santiago x Don Noé) was obtained by crossing the triticale Don Santiago INTA (AABBRR, 2n = 6x = 42) with the trigopiro Don Noé INTA (AABBDDJJ, 2n = 8x = 56). The number of chromosomes for the F 1 was 2n = 49, the most frequent meiotic configuration being 14 bivalents and 21 univalents. The univalents were situated in the periphery of the equatorial plane, whereas the bivalents were located in the central zone. The chromatids in some of the univalents split when bivalents underwent reductional division in anaphase I. There were few laggard chromosomes or chromatids at this phase. The number of chromosomes (2n = 48-58) was high and variable, and the number of bivalents per cell (18-23) also high in F 3 individuals. In all F 8 tricepiros (Don Santiago x Don Noé), F 12 tricepiros (Cumé x Horovitz) and F 12 tricepiros (Cumé x Don Noé), the number of chromosomes (2n = 42) was the same, these retaining the rye genome, as demonstrated by GISH and FISH. These new synthesized allopolyploids constitute interesting models for investigating the evolutionary changes responsible for diploidization, and the chromosomal and genomic re-ordering that cannot be revealed in natural allopolyploids.

Mitotic and meiotic behavior of rye chromosomes in wheat - Psathyrostachys huashanica amphiploid x triticale progeny

“…It appears that the number of rye chromosomes increased spontaneously before the F 3 generation. A similar tendency has been reported in several previous studies (Bernardo et al, 1988;Fradkin et al, 2009). In the present study, this result may be attributed to 2 consecutive meiotic events: the equational division of rye univalents occurring at anaphase I and the production of unreduced gametes.…”

“…Parts of the chromatids lagged and failed to enter the newly produced nuclei, and in turn generated micronuclei at telophase I and II. These events have been observed in other wheat-rye combinations (Liusikov et al, 2005;Silkova et al, 2008;Fradkin et al, 2009). In the second, the immobilized univalents in the periphery of cells across meiosis could give rise to the production of micronuclei.…”

“…Detailed cases have been described in some species of Brachiaria (Risso-Pascotto et al, 2004), Fritillaria (Darlington, 1939), Paspalum (Adamowski et al, 1998), wheat (Lukaszewski, 2010), and combinations of wheat x related species in Triticeae such as Aegilops kotschyi Boss. (Tiwari et al, 2010), Elymus trachycaulus (Link) Gould ex Shinners (Friebe et al, 2005), and rye (Liusikov et al, 2005;Fradkin et al, 2009).…”

Chromosome and genome composition of a Triticum × Thinopyrum hybrid by classical and molecular cytogenetic techniques

“…Genomic in situ hybridization (GISH) using the total genomic DNA as a probe is a useful technique to detect alien chromatin in wheat-alien species amphiploids, distinguish parental genomes, and analyze genome organization in interspecific and intergeneric hybrids and allopolyploid species (Cai et al 2001;Ferrari et al 2005;Fradkin et al 2009;Le et al 1989;Molnár-Láng et al 2000;Schwarzacher et al 1989). …”