Impact of low linolenic acid content on seed yield of winter oilseed rape (Brassica napus L.)

Abstract

An essential quaUty improvement of rapeseed oil can be obtained by reduction of its linolenic acid (C18:3) content from about 10% to less than 3% of the total fatty acids. Genotypes low in C18:3 have been developed by mutagenesis. The initial summer rapeseed mutant had been low yielding and highly susceptible to various diseases. It has been debated whether the low C18:3 character can be successfully combined with high seed yield for physiological reasons. Therefore, the low linolenic character of mutant M48 was transferred into high-yielding genotypes by repeated backcrossing to well-adapted low erucic acid, low glucosinolate (00-) winter rapeseed cultivars. Lines with low C18:3 content were selected from BC3 and BC4 generations and examined in 1990-95. Positive selection response for seed yield was shown to continue over the years. Presently, the best lines are yielding as well as the control cultivars being equivalent also in oil and glucosinolate contents.In order to test the effect of a low C18:3 content on seed yield, plants with low and with high C18:3 content, respectively, were selected from 16 segregating BC5-F2 populations and bulked to form 32 F3 populations. These 'isogenic' bulk populations were tested for field performance at four locations in 1995. The results show that C18:3 content of the seed oil is not associated with seed yield, oil content, beginning of flowering, plant height and disease resistance. Means of relative seed yield for the high and the low linolenic F, bulk populations were not significantly different with 88.0% and 86.9% of the control cultivars, respectively. There was a significant interaction between genotypes with high or low C18:3 content and location. This shows that under specific environmental conditions a low C18:3 content may be either favourable or unfavourable. The results indicate that the low C18:3 character of the original mutants per se does not cause a decrease in seed yield, oil content or general field performance.

Oil Crop Breeding and Genetics

“…Improvement of both oil and meal in oilseed rape by reducing erucic acid content of oil (canola quality) and glucosinolate content of meal are two most prominent milestones contributing to the expansion of world oilseed rape acreage from less than 10 million hectares in the early 1970s to more than 27 million hectares in 2005 (FAO-STAT 2007). Moreover, high oleic (Schierholt et al 2001) and low linolenic (Ru¨cker and R¨obbelen 1996) oilseed rape represent further improvements of nutritional value and oxidative stability. Relevant changes in fatty acid composition have also been achieved in sunflower, soybean and linseed (Table 1.3).…”

Inheritance and variation of erucic acid content in a transgenic rapeseed (Brassica napus L.) doubled haploid population

“…Following trierucin analysis remaining parts of the oil samples were transferred to a new tube and left over night on a hot plate at 37.5°C to evaporate the solvent. Fatty acids composition were analyzed by GLC according to Rücker and Röbbelen (1996). Trierucin and fatty acids are expressed as % of the sum of all triglycerides and fatty acids, respectively.…”

Modification of Fatty Acid Profiles of Rapeseed (Brassica napus L.) Oil for Using as Food, Industrial Feed-Stock and Biodiesel

“…In rapeseed breeding, efforts have made for many years focusing on increasing the oleic acid content. In Germany, mutation experiments were started about 20 years ago and first mutant with HO acid content was selected by Rücker and Röbbelen (1996). Genetic studies confirmed that the selected mutant line was inherited by single gene in an additive manner (Schierholt et al 2001).…”