In vitro induction of haploid plants from unpollinated ovules and ovaries of the sugarbeet (Beta vulgaris L.).

Haploid plantlets from male fertile and male sterile sugarbeet plants could be induced at frequencies up to 2.2% using ovule culture. Ovary culture on media without charcoal resulted in a similar induction frequency. Plant development was inhibited by callus development originating from the mother tissue. When the callus parts were removed and the ovule transferred to a new medium without 2,4 D, callus formation could be inhibited by adding 0.5% charcoal to the medium. Up to 6.1% haploids were induced. Chromosome counts in leaf tips, chloroplast counts and isozyme patterns revealed that all plants were haploid and originated from the haploid cells of the embryo sac. Root tips showed spontaneous polyploidisation.