Cytogenetic Studies in Avena, XIII. The relationship of synaptic factors between tetraploid and hexaploid species

Abstract

Comparative observations were made on 2 kinds of F1 plants obtained by the cross between the wild tetraploid species Avena barbata and the monosomic-c of A. sativa, i.e., on the pentaploid (chromosome nos.= 35) with 1 c-chromosome (AABB''C) vs. the monosomic pentaploid without c-chromosome (chromosome nos.=34) (AAB''BC-c). The 34-chromosome plants were shorter in height and showed the wild grain character, as a result of being devoid of c-chromosome. In regards to chromosome pairing, no significant differences were found between the 2 types in the average number of pairs or of chiasmata per cell at metaphase I. It was demonstrated that the meiotic pairing between the homologous chromosomes from the 2 species can occur in the absence of the synaptic factor of A. sativa, as the chromosomes are probably paired in the presence of the synaptic factor (s) of A. barbata.