. 2007. Genotypic and environmental variation in grain, flour, dough and bread-making characteristics of western Canadian spring wheat. Can. J. Plant Sci. 87: 679-690. Wheat (Triticum aestivum L.) grain, flour, dough and bread quality characteristics are strongly influenced by growing-season weather conditions. Understanding the impact of genotype, environment, and their interactions on Canadian wheat quality is important for Canada to maintain its high standard for delivery of consistent quality wheat to domestic and international customers. The effects of genotype, environment and genotype by environment (G × E) interaction on numerous grain, flour, dough and bread-making characteristics were assessed. The Canadian Western Red Spring (CWRS) cultivars were AC Barrie, Superb, AC Elsa, and Neepawa; the Canadian Prairie Spring (CPS-white) cultivar was AC Vista; and the Canadian Western Hard White Spring (CWHWS) cultivar was Snowbird. These genotypes were grown at five locations across the Canadian prairies in 2 yr to provide a total of 7 site-years of milling quality wheat for analysis. Genotype, environment and their interactions had significant effects on most parameters tested. The relative magnitude of the environmental contribution to wheat quality variance, depending on the trait, was considerably larger (14 to 89%) than the variance contribution of either genotype (0 to 33%) or G × E interaction (0 to 17%). The greatest environmental contribution to total variance (83%) was, on average, for grain traits including yield. Genotypic contribution to variation was greatest (~15%) for flour characteristics. The G × E interaction contributed relatively little to total variance and was comparable for flour, dough and bread properties (~6.5% on average). This large difference in variance between environmental and genotypic influences clearly demonstrates the importance of growing-season weather impacts on yield and quality for adapted bread wheat genotypes and strategies to mitigate these effects are discussed.Key words: Wheat, bread-making quality, Canadian prairies, environment, genotype, genotype by environment Finlay, G. J., Bullock, P. R., Sapirstein, H. D., Naeem, H. A., Hussain, A., Angadi, S. V. et DePauw, R. M. 2007. Variations génotypiques et environnementales du grain, de la farine, de la pâte et de la panification du blé de printemps de l'Ouest canadien. Can. J. Plant Sci. 87: 679-690. Les conditions météorologiques durant la période végétative exercent une profonde influence sur le grain du blé (Triticum aestivum L.), sa farine, la pâte et la panification. Pour que le blé canadien garde sa réputa-tion de qualité auprès de la clientèle canadienne et étrangère, il importe de comprendre l'incidence du génotype et de l'environnement ainsi que de leurs interactions. Les auteurs ont évalué l'effet du génotype, de l'environnement et de l'interaction génotype × environnement (G × E) sur de nombreuses caractéristiques du grain, de la farine, de la pâte et de la panification. Les essais ont porté sur les cultivar...