Origin of androgenetic callus and haploid geranium plants

Abstract

Geranium (Pelargonium hortorum Bailey) anthers, containing uninucleate immature pollen at the tetrad stage, were incubated on a modified White's medium at 28 ± 2 °C with 16 h light alternating with 8 h darkness at 23 ± 2 °C. The daughter cells derived from pollen were observed as a colony of four cells after 9 days, and 20 cells after 18 days. Nuclei of cells of the colonies formed were large and diffuse similar to the vegetative nuclei. Examination of dissected anthers after an incubation period of 1 month showed that the induced calli were in the pollen grain sac and not attached to the anther connective tissues. Established calli were subcultured on Murashige and Skoog medium for organoid differentiation. Plants differentiated from the anther callus of varieties Sincerity, Pink Camelia, and Salmon Irene were haploid (2n = 18), had single florets with five petals, and set viable seed.