Genotypic and environmental effects on saturated fatty acid concentration of canola grown in Manitoba

Abstract

The low saturated fatty acid concentration of canola oil relative to other vegetable oils has resulted in a favourable market share for canola. Understanding the effects of genotype and environment on saturated fatty acid concentration will facilitate Brassica napus breeding efforts aimed at maintaining or reducing saturate levels in the seed oil. Canola-quality B. napus samples from the Manitoba Crop Variety Evaluation Team (MCVET) trials in 1999, 2000 and 2001 were tested for fatty acid composition, oil concentration and protein concentration. Weather data were obtained from nearby weather stations. The majority of the variation in total saturates for the cultivars studied was attributed to variation in palmitic acid (C16:0) due to the genotype main effect and variation in stearic acid (C18:0) due to the genotype and environment main effects. The variation due to the genotype x environment interaction was small relative to the main effects for the individual saturated fatty acids. C18:0 and arachidic (C20:0) acid concentrations were correlated between genotypes, suggesting pleiotropy or that these traits are controlled by linked genes in the cultivars tested. The data also suggested that C16.0 and C18:0 acid concentrations are controlled by different genes. C18:0, C20:0 and behenic (C22:0) acid concentrations were correlated across environments, but did not correlate with C16:0 concentration. Relationships between weather variables and fatty acid composition, oil concentration and protein concentration were not established. Additive Main effects and Multiplicative Interaction (AMMI) analysis revealed that some canola cultivars were more stable than others with regard to total saturates over environments.