'Plant Breeding: Sustaining the Future' Abstracts of the XVIth EUCARPIA Congress, Edinburgh, Scotland, 10-14 September 2001 SELECTION OF RAPESEED MUTANTS WITH IMPROVED TOCOPHEROL COMPOSITION J. OLEJNICZAK, C. MOELLERS, V. MARWEDE, A. WOJCIECHOWSKI Institute of Plant Genetics Polish Academy of Sciences, StrzeszySigmaska 34, 60-479 PoznaSigma, Poland

Tocopherols are important natural antioxidants that inhibit lipid oxidation in food stuffs and biological systems by donating their phenolic hydrogens to lipid free radicals.  Mutagenesis has successfully been applied to develop mutants with improved oil quality in Brassica species without alterations in tocopherol content and composition.  A large collection of lines derived from Brassica napus DH-line-0120 treated with sodium azide and N-nitroso-N-methylurea was evaluated in greenhouse and field experiments in 1999 and 2000.  8561 single M4-plants were harvested in the field in 2000.  Biochemical analysis was performed by near infrared reflectance spectoscopy (NIRS) for oil, protein, glucosinolates and fatty acids.  Variation for the above traits was found, particularly for oil (23.1-54.5%) and protein (15.1-32.2%) content.  Tocopherol content and composition of seeds determined by HPLC were strongly affected.  Contents ranged from 169-483 ppm, as compared to initial genotype DH 0-120 (345±22 ppm).  Tocopherol composition of selected mutants expressed as the ratio alpha to gamma tocopherol content was in the range of 0.25-1.46 with a coefficient of variation of 18.7% (cv) compared to line DH-0.120 (0.55±0.09).  A few of these mutants also showed considerably increased oleic acid contents (GLC) and decreased glucosinolate contents (HPLC).  Environmental conditions during vegetation period strongly influenced total tocopherol content and composition in tested M4 mutants.  Variability of alpha to gamma ratio was higher under greenhouse conditions (0.55-5.04) compared to field conditions (1.0-3.76).  The results suggest that chemical mutagenesis appears to be an effective tool for improving variability of tocopherol content and composition.