In vitro selection for oleic and linoleic acid content in segregating populations of microspore derived embryos of Brassica napus

Microspore derived embryos (MDEs) in Brassica napus contain large amounts o f storage lipids which show a genotype specific fatty acid composition (FAC ). One cotyledon of regenerating emblyos can be dissected at an early stage during the in vitro culture and used for fatty acid analysis. Thus, in bre eding programmes to modify oil quality, only MDEs having the desired FAC ne ed to be regenerated to plantlets and transferred to the greenhouse. In the present study the applicability of this method for the selection of a high oleic acid content and a low linoleic acid content in the seed oil has bee n tested by crossing a Brassica napus mutant line having a high oleic acid (C18:1) content in the seed oil (75%) with a wild type doubled haploid line with 62% C18:1 in the seed oil. Microspore culture was applied to the F1 p lants. In total 59 MDEs were obtained, from which 31 were cultured with and 28 without 15 mu M abscisic acid for 3 weeks in vitro. One cotyledon was d issected under aspetic conditions and used for fatty acid analysis. The rem aining part of the embryos were further regenerated to plantlets and transf erred to the greenhouse to obtain seeds after self pollination. Seeds harve sted from the doubled haploid lines in the greenhouse were used for fatty a cid analysis and also for growing in the field. The abscisic acid treatment of the MDEs generally improved the correlations for linoleic and oleic aci d between the MDEs and the seeds harvested in the greenhouse and the field. The correlations ranged from 0.68** to 0.81**. This indicates that selecti on for high oleic acid can be started already during an early stage of the in vitro culture.