Microspore mutagenesis in transgenic oilseed rape for the modification of fatty-acid composition
Sonntag, K.(Institute of Agricultural Crops, Gross Luesewitz (Germany). Federal Centre for Breeding Research on Cultivated Plants)E-mail:[email protected] | Rudloff, E.(Institute of Agricultural Crops, Gross Luesewitz (Germany). Federal Centre for Breeding Research on Cultivated Plants)
One of the first successful applications of the haploid embryogenic system in Brassica was aimed at mutagenesis and subsequent selection for desirable traits. A major advantage of the haploid embryogenic system for the selection of fatty-acid mutants is that analysis can be performed with only one of the two cotelydons while the remainder of the embryogenic tissue is available for plant regeneration. In the present study the applicability of the haploid technique of oilseed rape (Brassica napus L.) cv. 'Drakkar' transformed with the thioesterase gene C/FatB4 from Cuphea lanceolata combined with in vitro mutagenesis for the selection of a high myristic-acid (C14:0) content and a lower ratio of palmitic acid/myristic acid (C16:0/C14:0) in the seed oil was tested. The embryogenic capability of isolated microspores varied between 0.03 and 2.6 embryos per bud. After ultraviolet-light (UV) treatment only 3 lines regenerated to plants. Applying an UV-dose of 0.005 J cmE-2 resulted in 74 regenerants from which 23% diploids were obtained. The fatty-acid composition of the different genotypes of the corresponding doubled-haploid lines displayed some changes but there was no clear evidence for their mutagenic nature. The offspring of nine additional mutagenised plants were studied and these results are presented.
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