Obtention of haploid plants by ovaries and ovules culture in onion (Allium cepa L)

In vitro gynogenesis in onion plants was studied in Val 14 INTA and Torrentina population. Sterilization treatments were tested, the spraying of umbels with alcohol 96 degrees was selected. Different conditions and culture media were assayed. The highest percentages of growing ovaries were obtained with the medium proposed by Muren: Gamborg et al.(1968) medium and 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BA), both used at 2 mg/l and 10 % sucrose. Light and growth regulators would be of great importance for the first stages of the gynogenesis. Val 14 INTA showed greater potentiality on ovaries growth than Torrentina. Storage of the inflorescences is possible when they are placed at low temperatures during 2 weeks before in vitro culture. The embriogenic potential is not modified, allowing the enlargement of the in vitro introducing period. From a total of 2640 cultured ovaries, it was possible the induction of 5 haploid plants (8 chromosomes). The very low yields of haploid plants is discussed, taking in mind that totipotency to produce normal plantlets, seems to happen during a very short time, immediately after cell meiosis. The present paper reports the first results in haploid formation in cultures of ovaries from unpollinated flowers via gynogenesis in Allium cepa Val 14 INTA cv.