Abstract
Seed fatty acid (FA) composition, oil and protein (meal) was assessed on five canola (Brassica napus) varieties in 14 cropping environments in southern Australia, including several low rainfall drought-stressed environments. We modelled the relationship between seed quality attributes and growing season rainfall and temperature using a linear mixed model. Variance components for variety and years within locations were relatively large, but variance components for variety x environment interaction were small or insignificant for most seed quality traits. Mean oleic acid content varied from 57% in 'Surpass 300TT' to 62% in 'ATR-Beacon'. As growing season rainfall decreased from 300 mm (moderate) to 150 mm (severe drought stress), mean oleic acid decreased by 3.8%, linoleic acid increased by 2.0%, linolenic acid increased by 1.7%, and saturated FA decreased by 0.4%. Seed oil (% dry weight) decreased by 3.2% and protein in meal (% dry weight) increased by 3.9% across the same rainfall range. High oleic acid composition was associated with higher rainfall and cooler average minimum and maximum temperatures during the growing season.