Exploring the influence of weather on gluten strength of hard red spring wheat (Triticum aestivum L.) on the Canadian Prairies

Wheat gluten strength is a very important factor in bread-making, and can vary considerably with genotype, management and growing-season weather conditions. The Canadian Prairies experience high variability in weather conditions both within and between years, which impact spring wheat gluten strength and bread-making quality. This study aimed to identify climatic factors that affect spring wheat gluten strength and the growth stages when the impact is greatest. Nine hard red spring wheat genotypes of the Canada Western Red Spring (CWRS) class were grown in replicated field trials in nine locations across the Prairies over three years, 2015 through 2017. Agronomic and meteorological data were collected and used to derive 98 agroclimatic variables which were assessed for their impact on eight different response parameters of gluten quality including dough mixing and protein composition. Results clearly showed the opposing effects of temperature and precipitation on wheat gluten strength; especially during the late anthesis to grain filling growth stage. Higher temperatures around late anthesis to grain filling periods were associated with stronger gluten; while higher precipitation during the same wheat growth stages were linked to weaker gluten. Multiple linear regression (MLR), penalised ridge regression (PRR) and principal component regression (PCR) models selected similar weather variables as the most important affecting each of the various gluten strength parameters. These were slightly different from those selected by the partial least squares regression (PLSR) and random forest regression (RFR) models. The PCR, PLSR and RFR models outperformed the MLR and PRR models as indicated by lower root mean squared error and mean absolute error produced by the former.