C-banding in 6x-Triticale x Secale cereale L. hybrid cytogenetics.

The meiotic behaviour of F1 hybrids of hexaploid Triticale that differed in their genotypic or chromosomic constitution, and diploid rye, was investigated. Meiotic analysis were done by Feulgen and C-banding staining methods. A differential desynaptic effect in the hybrids was detected and explained in terms of genetic differences in pairing regulators. The high homoeologous pairing (A-B wheat chromosomes and wheat-rye chromosomes) observed in the hybrids can be explained in terms of an inhibition of the effect of a single dose of the Ph allele of the 5B chromosome produced by two doses of the 5R chromosome. The higher homoeologous pairing detected in the hybrid 188 x 'Canaleja' could be the overall result of the balance between the Ph diploidizing system (1 dose), the pairing promoter of the 5R chromosome (2 doses) and that of the 3D chromosome (1 dose coming from the parental line Triticale with the substitution 3R by 3D).