High Frequency Production of Doubled Haploid Rapeseed Plants by Direct Colchicine Treatment of Isolated Microspores

Abstract

Techniques for microspore culture of Brassica napus have been improved rapidly, and embryogen-esis has been achieved in a wide range of genotypes. Plants regenerated from microspore-derived embryoids can be haploid, diploid or polyploid. From rapeseed microspore culture it is reported that 70%-90% of regenerated plants are haploid. The usual methods of chromosome doubling involve soaking roots (most common) or whole plants in a colchicine solution, or culturing plantlets in colchicine-containing medium in the greenhouse. Other alternatives are injecting colchicine into the secondary buds or applying colchicine-soaked cotton plugs to axillary buds.