Production of haploids in <i>Gerbera jamesonii</i> via ovule culture: influence of fall versus spring sampling on callus formation and shoot regeneration

Abstract

The unfertilized ovules of one clone of Gerbera jamesonii H. Bolus ex Hook. f. were cultured in vitro as a means of producing haploid plants. A total of 4715 ovules were cultivated on 17 media during two distinct periods of the year. All the media tested, except the ones containing 0.5% w/v of activated charcoal, were able to sustain the formation of callus. When these calli were transferred to the regeneration medium, shoot differentiation occurred in about 2 weeks. Usually, callus induction occurred at a higher frequency during the fall experiments. However, the calli produced in the spring displayed a higher morphogenetic capacity. Chromosome and chloroplast counts performed on randomly selected plants revealed that 76% of the regenerants were haploid and 24% were diploid.