| Résumé | Haploidy/doubled haploidy methodology is commonly used in many agronomically important crops to speed the development of new cultivars. There are a number of advantages in using haploidy technology in both practical application (varietal development, mutagenesis, transformation) and basic research (genomics, biochemical, and physiological studies). Haploid plants are commonly produced using one of four methods: culture of anthers or microspores (androgenesis), culture of unfertilized ovules (gynogenesis), interspecific or intergeneric crosses followed by chromosome elimination, and by pollination with irradiated pollen. The most efficient method depends on the species. In many species, the culture of isolated microspores or anthers is the most frequently used method of haploid production. With this method, every microspore is potentially capable of regenerating into a viable embryo and each plant would therefore represent the variation which exists in the population of microspores. Plant regeneration occurs either by direct embryogenesis or through callus formation followed by embryogenesis or organogenesis. There are a number of factors influencing embryogenesis from anther/microspores or ovaries/ovules including genotype, donor plant growth conditions, stage of explant development, composition of the culture medium, and environmental conditions during culture. The frequency of embryo production will depend on whether or not these conditions are optimal and varies depending on the species. Compared to some agronomic species, there has been very little work on doubled haploidy in ornamental species despite the potential benefits. |
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