Microspore embryogenesis is one of the main procedures utilized for obtaining doubled haploids, which are used for breeding and producing superior F1 hybrid cultivars. The success of established androgenesis approaches is unsatisfactory in many species and genotypes, prompting the development of new methods for inducing haploids. This thesis discusses the addition of chemical substances such as the TDZD-8 inhibitor of mammalian GSK-3, which enhances the efficiency of microspore embryogenesis in oilseed rape. Additionally, promising results were shown in experiments with 5-azacytidine, influencing cell reprogramming through DNA demethylation, resulting in a significant increase in regenerated embryos in oilseed rape and barley. BIX-01294, with its inhibitory effect on histone lysin methyltransferases, reduces the amount of histone methylation and thus induced reprogramming of barley and rapeseed microsporse. Triostatin A inhibits plant histone deacetylases, thus deregulating transcription factor access to DNA molecules, causing microspore reprogramming. In oilseed rape this represents a key step in microspore embryogenesis of recalcitrant genotypes, yielding over 600% better results compared to controls. Phytosulfokine alpha, a chemical functioning as a peptide growth factor, was successful in wheat and triticale microspore cultures, with the highest applied concentration yielding the most successful embryo regeneration. These methods currently show promising results in specific species, and in the future, some may become widely adopted in breeding and research programs of genotypes recalcitrant to current inducing techniques.
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