Tocopherols are natural antioxidants found in all vegetable oils. They are important dietary nutrients and thus breeding for increased tocopherol content is a new and important objective in canola (Brassica napus L.). Tocopherols exist in four forms (α‐, β‐, γ‐, and δ‐tocopherol) differing in molecular structure and biological effectiveness. In the seed oil of canola, mainly α‐ and γ‐tocopherol are found with an α/γ‐tocopherol ratio of about 0.5. Three canola populations of doubled haploid lines were grown in three to four field environments to analyze genetic variance and genotype × environment interactions as well as heritability of tocopherols and correlations with other seed components. Significant genotypic differences occur, but large genotype × environment interactions are the major source of variation. Heritability of tocopherol was low in all three populations; the estimates ranged from 0.23 to 0.44 for α‐tocopherol and from 0.33 to 0.50 for γ‐tocopherol. Heritability for tocopherol content is considerably lower than heritability of oil content (0.56–0.90), protein content (0.43–0.76), or glucosinolate content (0.91–0.95). No correlation between α‐ and γ‐tocopherol or between tocopherol and oil, protein, and glucosinolate content was detected. Individual tocopherols can be increased independently of each other and without affecting other major quality traits.

Tocopherols are natural antioxidants in vegetable oils and are important dietary nutrients. Enhanced tocopherol content has become an important objective in oilseed rape breeding. A segregating DH population was tested for 2 years at two locations in replicated field trials. Genotypic differences occurred for a-, c-and total tocopherol content as well as a/c-tocopherol ratio, but highly significant genotype · environment interactions resulted in low heritabilities. Using a mixed-model composite interval mapping approach between one and five QTL with additive and/or additive · environment interaction effects could be mapped for a-, c-and total tocopherol content and a/c-tocopherol ratio. In addition, one to six locus pairs with epistatic interaction effects were identified, indicating a strong contribution of epistasis to trait variation. In total, the additive and epistatic effects explained between 28% (a-tocopherol content) and 73% (total tocopherol content) of the genotypic variance in the population, with individual QTL and locus pairs contributing between 7.5 and 29.2% of variance. Considering the low heritabilities of the tocopherol traits, the results of this study indicate that marker-assisted selection may be an efficient strategy in a breeding program for enhanced tocopherol content in rapeseed.

to environmental factors (Dolde et al., 1999; Marquard, 1976 Marquard, , 1990. Previous research revealed a variation of Tocopherols are natural antioxidants found in all vegetable oils.230 to 1000 mg kg Ϫ1 for total tocopherol content in seed They are important dietary nutrients and thus breeding for increased tocopherol content is a new and important objective in canola (Bras-oil of single plants grown in the same environment and sica napus L.). Tocopherols exist in four forms (␣-, ␤-, ␥-, and ␣/␥-tocopherol ratio was ranged from 0.54 to 1.70 ␦-tocopherol) differing in molecular structure and biological effective-(Marwede et al., 2003). To evaluate genotype ϫ enviness. In the seed oil of canola, mainly ␣and ␥-tocopherol are found ronment interactions and heritability of ␣-, ␥-, and total with an ␣/␥-tocopherol ratio of about 0.5. Three canola populations tocopherol content and ␣/␥-tocopherol ratio, three douof doubled haploid lines were grown in three to four field environbled haploid populations of different genetic origin were ments to analyze genetic variance and genotype ϫ environment intergrown in three to four field environments. Also, correlaactions as well as heritability of tocopherols and correlations with tions between tocopherol content and other seed quality other seed components. Significant genotypic differences occur, but large genotype ϫ environment interactions are the major source of traits were investigated. variation. Heritability of tocopherol was low in all three populations; the estimates ranged from 0.23 to 0.44 for ␣-tocopherol and from MATERIALS AND METHODS 0.33 to 0.50 for ␥-tocopherol. Heritability for tocopherol content is considerably lower than heritability of oil content (0.56-0.90), protein

McVetty, P. B. E., Cuthbert, J. L., Marwede, V., Paulmann, W., Sass, O., Duncan, R. W., Fernando, W. G. D., Li, G. and Zelmer, C. D. 2014. HYHEAR 1 hybrid Roundup Ready™ high erucic acid, low glucosinolate summer rape. Can. J. Plant Sci. 94: 453–455. HYHEAR 1 summer rape (Brassica napus L.) is the world's first hybrid Roundup Ready™ high erucic acid, low glucosinolate cultivar. On average, HYHEAR 1 yielded 33% more seed, 23 g kg−1 more seed oil but 17 g kg −1 less meal protein than MillenniUM 03 high erucic acid, low glucosinolate, open pollinated population summer rape. HYHEAR 1 has an erucic acid content of 52.2% in isolated field trials of HEAR lines and is adapted to the southern B. napus growing regions of western Canada.