Effect of temperature variation during grain filling on wheat gluten resistance

The objective was to investigate effects of natural variation in temperature during grain filling on wheat (Triticum aestivum L) gluten quality. Seventeen field trials with four different varieties were conducted during the years 2005–2008. Temperature records were obtained from automatic weather stations located near the field trial sites. The period from heading to yellow ripeness was divided into 20 sub-phases of equal thermal time units, and a last sub-phase comprising the seven days after yellow ripeness. Partial Least Squares Regression was used to relate the temperature records of the different sub-phases to gluten quality analysed by the Kieffer Extensibility test and the SDS sedimentation test.A large temperature variation during grain filling was recorded between different seasons, and between locations within season. The latter was mainly caused by variation in sowing time, giving different courses of temperature during grain filling. Major variation in gluten resistance was observed, ranging from Rmax of 0.13 to 1.12 N within a genotype. A higher mean temperature from heading to approximately midway in the grain filling period was positively related to gluten quality. A weaker gluten resistance was observed when the diurnal mean temperature in these periods dropped below 18 °C.