The Chromosome Variation of Barnardia japonica Polyploid Complex Uncovered by Giemsa-C Banding

Barnardia japonica Thunb.is a polypliod complex occupying East Asia,and the chromosome variation was analyzed by the Giemsa-C banding method for 24 populations of this complex.No variation was found in Giemsa-C banding between and within the most populations of AA and BB cytotypes and subcentromeric bands present on a₂ chromosomes in AA cytotype and b₁ in BB.There is no variation within each of the tested populations in AABB cytotype,but there is between the populations.AABB populations in Central China have the same and abundant Giemsa-C bands,but only b₁ chromosomes have subcentrimeric bands in Population Yuanbaoshan,and only a₂ and b₁ have subcentrimeric bands in Population Lingyanshan.It is concluded that subcentrimeric bands on the a₂ and b₁ are possibly rRNA genes and heterozygosity at this chromosomal region of individuals in Populations Daqing and Wenxian may be due to shift of its some copies between homologous chromosomes;Abundance in Giemsa-C bands in populations in Central China is probably reflections of the depression of some duplicated genes at the beginning of its origin,and this complicated DNA probably was deleted during the evolution of this new tetrapolyploid;Chromosomal structure changes more easier in BB than in AA cytotype.