Polyploidy in Muscari neglectum (Asparagaceae) by analysis of karyotype and Giemsa C-banding patterns

This study provides new karyological information on polyploid cytotypes of Muscari neglectum. Classical cytogenetic with the Feulgen technique and banding with Giemsa was used. Pentaploid, hexaploid and heptaploid levels of ploidy are here reported. The complement of the rare heptaploid cytotype consisted of 2n=7x=63: 49m+14sm chromosomes. Two heptaploid specimens with chromosome numbers 60 and 62 were also found. Karyotypes were symmetrical, with metacentric chromosomes more numerous than submetacentric. The morphometric parameters MCA and CVCL were used for the evaluation of karyotype asymmetry. For the first time, a detailed study using Giemsa C-banding is reported. The C-banding patterns included centromeric and terminal bands. In the cytotype with 62 chromosomes, the banding patterns identified the presence of a chromosome with terminal band in both arms. To explain the origin of this karyotype, we suggest that fusion occurred between a group IV chromosome and a group V chromosome. The relationship between the polyploid cytotypes of M. neglectum is discussed.