MICROSPORE CULTURE IS SUCCESSFUL IN MOST CROP TYPES OF BRASSICA-OLERACEA L

Microspore culture was shown to be applicable to a broad range of accessions belonging to six horticulturally important crop types of Brassica oleracea: broccoli, white cabbage, cauliflower, savoy cabbage, Brussels sprouts and curly kale. Of 64 accessions tested 86% were responsive. Large genotypic differences were found in number of embryos produced per flower bud, and in frequency and mode of regeneration of plants from embryos. B. oleracea was characterized by a strong asynchrony of microspore development within single buds. Microspore populations optimal for culture contained a large proportion (10-40%) of binucleate pollen. An initial high temperature treatment was essential for microspore embryogenesis. Growth conditions of the donor plants during inflorescence formation were less critical.