Identification of high oleic acid germplast from the T2 progeny of the transgenic Brassica napus L.

The selfed seeds of 49 T_1 individuals from the transgenic line W-4,transformed by the construct containing ihpRNA targeted to the endogenous fad2 gene of Brassica napus L.,were harvested and the seed fatty acids were analyzed by gas chromatogram.The results showed that the variation range of oleic acid level among the T_2 seeds of 49 progenies was 55.87%to 84.73%much wider than that of the control,and that of the control was about 55.28%to 67.43%. There were 19 individuals,accounting for 38.8%of the total plants,that contained greater than 75%oleic acid in the seed oil,including 11 individuals with more than 80%oleic acid,which accounted for 22.4%of the total plants.These high o- leic acid lines were also found considerable reductions in linoleic acid and linolenic acid.The oleic acid parameter(ODP) of the high oleic acid lines was only 5%-12%much lower than that of the control,which had an ODP value of around 20%-36%.Based on the ODP value,it could be assumed that about 60%-83%FAD2 activity in the seeds of high oleic acid lines was effectively inhibited,probably owing to the expression of ihpRNA for fad2 gene in the seeds of the transgenic plants,thereby preventing the oleic acid to be desaturated to linoleic acid and linolenic acid further.