Polyploidy in the Potato

Abstract

RECOGNITION of the polyploid nature of various economic plants has become increasingly important, and the type of polyploidy is also of prime importance in the study of phylogeny within any genus or family of plants. Various cytological and genetical criteria of polyploidy have been used, such as chromosome number, the number of nucleoli, polyvalent chromosomes in diakinesis, and tetraploid segregation ratios of genetic characters. In many plant genera, chromosome number together with the number of satellites, secondary constrictions and nucleoli (and where available with additional points in chromosome size and morphology) are sufficient to show the type of polyploidy and in some cases to provide adequate evidence as to how it has arisen¹. In the genus Brassica, even the ancestral species have thus been clearly recognized in several cases².