Meiosis en mutantes desinápticos con restitución cromosómica en Rhoeo spathacea (Commelinaceae)

this study was carried out with collected material of rhoeo spathacea in the states of veracruz, chiapas, tabasco, yucatan, quintana roo and michoacan, mexico. all material exhibited a diploid chromosome number (2n =12) in mitosis. in meiosis, all individuals showedring and /or chains at metaphase i. exceptionally several desynaptic mutants resulted desynaptic - sdr (dissociation of paired chromosomes). therefore, in meiosis rhoeo did not exhibit synapsis in parallel-fashion instead the chromosomes are united in end-to-end (no chiasmata-) fashion. then, there are not bivalents, no chiasmata-achiasmata- as there are not four chromatids two of which resulted sister-chromatids. but in anaphase i, there is high regular 6:6 disyuction and observed as "rings or donuts". in which short arms are oriented to the center of those figures. from selfed a desynaptic- sdr (gava 1.1) mutant, a progeny of 123 individuals resulted: 90 diploid-ring forming, 1 acrotrisomic (2n=13) equally ring-forming reverts its "meiotic behavior", but 29 diplandrogynous tetraploids (2n=24) and 3 hypertetraploids (2n=25) resulted desynaptics. the cytological behaviour is due to the fact that rhoeo is a dikaryon: diploids-ring forming and the trisomic also and present subgenome a, but polyploids present subgenome b which includes a desynaptic gene in both sister chromatids as result of restitution at second division(2n).