Hybridization studies in the genus Impatiens

The biosystematic relationships of Impatiens walleriana Hook. f. and other selected species were examined by means of hybridization experiments and cytological techniques. Both I. gordonii Home and I. usambarensis Grey-Wilson hybridized with I. walleriana. Meiotic abnormalities of the hybrids were determined by examining pollen mother cells. Meiosis was regular in the majority of cells in both of the hybrids, but I. walleriana × I. gordonii had more abnormalities than I. walleriana × I. usambarensis. Because of the meiotic abnormalities in the hybrids and the morphological differences between I. walleriana and I. gordonii, I. gordonii was confirmed as a distinct species. The status of I. usambarensis was not as clear because it was morphologically similar to I. walleriana, and the hybrid between the two species had fewer meiotic abnormalities. Both I. gordonii and I. usambarensis could be useful in a horticultural breeding program because they hybridize easily with I. walleriana.