The genus Actinidia is remarkable for the variation in ploidy both within and between taxa. There is a structured reticulate pattern of diploids, tetraploids, hexaploids, octoploids and decaploids in diminishing frequency within the genus. The basic chromosome number x = 29 suggests that diploids of Actinidia are in fact palaeopolyploids. The 2C-value for diploid Actinidia chinensis var. chinensis is about 1.53 × 109 bp. No assumptions should be made as to the ploidy of any particular genotype. Many taxa contain ploidy races and the ploidy of any genotype used in breeding programmes should therefore be checked. The ploidy of offspring should also be checked because they are not always at the expected ploidy, especially when they result from interploidy crosses or if the parents are autopolyploids.