Differentiation of triticale cultivars through FISH karyotyping of their rye chromosomes.

The aim of this work was to cytogenetically characterize triticale cultivars through fluorescence in situ hybridization (FISH) analysis of their rye chromosomes. In the present work, we studied six cultivars of triticale ('Cayú-UNRC', 'Cumé-UNRC', 'Genú-UNRC', 'Ñinca-UNRC', 'Quiñé-UNRC', and 'Tizné-UNRC'), released by the Universidad Nacional de Río Cuarto (UNRC), Córdoba, Argentina. The cultivars were obtained from the International Center for the Improvement of Maize and Wheat (CIMMYT) and improved for fresh forage, haymaking, and feed grain at UNRC. The distribution and organization of highly repetitive DNA sequences of Secale cereale (pSc74, pSc200, pSc250, and pSc119.2) using FISH analyses revealed a specific localization of the signals for several rye chromosomes, which allowed us to distinguish the cultivars. Cluster analysis showed a great cytogenetic similarity among the rye cultivars used to originate these hybrids. The knowledge of the variability among triticale cultivars is necessary to propose future crosses in breeding programs. This study will also be valuable to identify commercial seeds and to analyze the possible association between agronomic characters and the presence of certain rye chromosomes or specific regions in these chromosomes.

Cytological analysis of hybrids among triticales and trigopiros.

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.

Cytological analysis of hybrids among triticales and trigopiros

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 F1 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 F3 individuals. In all F8 tricepiros (Don Santiago x Don Noé), F12 tricepiros (Cumé x Horovitz) and F12 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.