Abstract: A switch to haploid embryogenesis is controlled by the activity of histone deacetylases (HDACs). Blocking HDAC activity with HDAC inhibitors (HDACi), e.g., trichostatin A (TSA), in Brassica napus, B. rapa, Arabidopsis thaliana, and Capsicum annuum male gametophytes leads to a large increase in the proportion of cells that undergo embryogenic growth. In B. napus, treatment with one specific HDACi (SAHA) improves the conversion (i.e., germination) of these embryos into seedlings. Existing methods of culturing microspores of angiosperm plants following stress to produce haploid embryos, haploid plants, and double haploid plants can be improved by adding HDACi to the culture medium. Advantageously, species hitherto recalcitrant to haploid embryogenesis via microspore culture are rendered useful when using HDACi. Haploid and double haploid plants are of industrial application in the plant breeding programmes.

Abstract: The present invention provides means for inhibiting the bolting and flowering of a Beta vulgaris plant, including an isolated nucleic acid, which can be used to produce a transgenic Beta vulgaris plant, where bolting and flowering is inhibited after vernalization. Furthermore, the invention discloses vectors, transgenic and non-transgenic, non-bolting plants and parts thereof, and methods for producing such plants.

Abstract: The present invention provides means for inhibiting the bolting and flowering of a Beta vulgaris plant, including an isolated nucleic acid, which can be used to produce a transgenic Beta vulgaris plant, where bolting and flowering is inhibited after vernalization. Furthermore, the invention discloses vectors, transgenic and non-transgenic, non-bolting plants and parts thereof, and methods for producing such plants.

Abstract: A switch to haploid embryogenesis is controlled by the activity of histone deacetylases (HDACs). Blocking HDAC activity with HDAC inhibitors (HDACi), e.g. trichostatin A (TSA), in Brassica napus, B. rapa, B. oleracea, Arabidopsis thaliana and Capsicum annuum male gametophytes leads to a large increase in the proportion of cells that undergo embryogenic growth. In B. napus, treatment with one specific HDACi (SAHA) improves the conversion (i.e. germination) of these embryos into seedlings. Existing methods of culturing microspores of angiosperm plants following stress to produce haploid embryos, haploid plants and double haploid plants can be improved by adding HDACi to the culture medium. Advantageously, species hitherto recalcitrant to haploid embryogenesis via microspore culture are rendered useful when using HDACi. Haploid and double haploid plants are of industrial application in the plant breeding programmes.

Abstract: The present invention provides means for inhibiting the bolting and flowering of a Beta vulgaris plant, including an isolated nucleic acid, which can be used to produce a transgenic Beta vulgaris plant, where bolting and flowering is inhibited after vernalization. Furthermore, the invention discloses vectors, transgenic and non-transgenic, non-bolting plants and parts thereof, and methods for producing such plants.

Abstract: A switch to haploid embryogenesis is controlled by the activity of histone deacetylases (HDACs). Blocking HDAC activity with HDAC inhibitors (HDACi), e.g. trichostatin A (TSA), in Brassica napus, B. rapa, B. oleracea, Arabidopsis thaliana and Capsicum annuum male gametophytes leads to a large increase in the proportion of cells that undergo embryogenic growth. In B. napus, treatment with one specific HDACi (SAHA) improves the conversion (i.e. germination) of these embryos into seedlings. Existing methods of culturing microspores of angiosperm plants following stress to produce haploid embryos, haploid plants and double haploid plants can be improved by adding HDACi to the culture medium. Advantageously, species hitherto recalcitrant to haploid embryogenesis via microspore culture are rendered useful when using HDACi. Haploid and double haploid plants are of industrial application in the plant breeding programmes.

Abstract: The invention relates to a method for producing haploid plant embryos, comprising providing microspores or pollen that comprise cell division inducing molecules; pollinating an embryo sac cell, in particular an egg cell, of the plant of which the haploid embryo is to be made with the microspores or pollen; allowing the microspores or pollen to discharge the cell division inducing molecules in or in the vicinity of the embryo sac cell, in particular the egg cell, to trigger division thereof to obtain a haploid plant embryo. When doubled haploid plant embryos are to be produced doubling of the chromosome number takes place at a certain stage after pollination, in particular during cell division or after obtaining the embryo. The invention further relates to the embryos thus obtained, plants regenerated therefrom and progeny thereof.