Striving for Stability in the Dough Mixing Quality of Spring Wheat under the Influence of Prolonged Heat and Drought

Abstract

The effects of prolonged heat and drought stress and cool growing conditions on dough mixing quality traits of spring wheat (Triticum aestivum L.) were studied in fifty-six genotypes grown in 2017 and 2018 in southern Sweden. The mixing parameters evaluated by mixograph and the gluten protein characteristics studied by size exclusion high-performance liquid chromatography (SE-HPLC) in dough were compared between the two growing seasons which were very different in length, temperature and precipitation. The genotypes varying in gluten strength between the growing seasons (≤5%, ≤12%, and ≤17%) from three groups (stable (S), moderately stable (MS), and of varying stability (VS)) were studied. The results indicate that most of the mixing parameters were more strongly impacted by the interaction between the group, genotype, and year than by their individual contribution. The excessive prolonged heat and drought did not impact the buildup and mixing time expressed as peak time and time 1–2. The gluten polymeric proteins (unextractable, %UPP; total unextractable, TOTU) and large unextractable monomeric proteins (%LUMP) were closely associated with buildup and water absorption in dough. Major significant differences were found in the dough mixing parameters between the years within each group. In Groups S and MS, the majority of genotypes showed the smallest variation in the dough mixing parameters responsible for the gluten strength and dough development between the years. The mixing parameters such as time 1–2, buildup, and peak time (which were not affected by prolonged heat and drought stress) together with the selected gluten protein parameters (%UPP, TOTU, and %LUMP) are essential components to be used in future screening of dough mixing quality in wheat in severe growing environments.

Impacts of heat, drought, and combined heat–drought stress on yield, phenotypic traits, and gluten protein traits: capturing stability of spring wheat in excessive environments

“…A 1°C-3°C rise in mean global air temperature is suggested to decrease wheat production by up to 28% (Shew et al, 2020;Zhang et al, 2022). In fact, in a previous study by our research group on field-grown wheat in Sweden, a yield reduction of up to 40% was observed under combined heat-drought conditions compared with rainy and cold conditions (Lama et al, 2022).…”

“…Eight spring wheat genotypes (Diskett, Happy, Bumble, SW1, SW2, SW3, SW4, and SW5) developed in the breeding program at Lantmännen Lantbruk, Svalöv, Sweden, were evaluated. The selected genotypes represented a range in gluten strength, as identified when grown in the field in our previous study (Lama et al, 2022). Diskett, Bumble, and SW3 represented genotypes with unstable gluten strength (>5% variation between years), while Happy, SW1, SW2, SW4, and SW5 represented genotypes with stable gluten strength (<5% variation between years) (Lama et al, 2022).…”

“…The flours were freeze-dried (Cool safe Pro, LaboGene) for 24 h in order to remove all moisture prior to SE-HPLC analysis. A two-step gluten protein extraction method was performed according to Lama et al (2022), with some modifications where collected supernatant (after first and second steps) in SE-HPLC vials was heated at 80°C for 2 min (to inactivate proteases) in a water bath according to Islas-Rubio et al (2006). Samples were run on the SE-HPLC system in triplicate.…”

“…This is because drought and heat impair the growth and development of different wheat plant organs, the rate of photosynthesis, fertility, the number of spikes, grain-filling, and nutrient uptake by the plant (Hurkman and Wood, 2011;Guzmań et al, 2016;Lan et al, 2022). Yield losses due to individual or combined heat-drought stresses have been observed in multiple countries in Europe, including Finland, Sweden, France, Belgium, and Switzerland (Kumar et al, 2020;Le Gouis et al, 2020;Lama et al, 2022). Areas such as the Mediterranean and southern Europe are experiencing higher impacts of heat-drought stress than other regions, causing major economic and food production losses [EEA (European Environment Agency), 2019].…”

“…Wheat quality is mainly determined by its major protein, gluten, the quantity and quality of which are often negatively impacted by heat and drought. For instance, the relatively high content of protein and strong gluten required in wheat bread flour (Kuktaite et al, 2004) is severely affected by intense heat and drought stresses (Lama et al, 2022). Total protein content and gluten content are reported to increase by 65% and 32%, respectively, under combined heat-drought stress compared with control conditions (Sattar et al, 2020).…”