Effect of high temperature and drought on the composition of gluten proteins in Martonvásár wheat varieties

Abstract

Finding and improving wheat cultivars with good adaptability to abiotic stress is an important objective in breeding programmes. An experiment was set up in the climate chamber of the Martonvásár phytotron to test the effect of heat and drought stress on two winter wheat varieties and one variety of durum. Wheat plants exposed to 35°C and drought during grain filling exhibited altered agronomic and grain quality characteristics. Drought was found to have a much greater influence on yield and quality than heat stress. Reductions in the unextractable polymeric protein fraction and the glutenin-to-gliadin ratio indicated poorer grain yield quality as a result of drought, despite higher protein content. Quality deterioration was observed after drought, while heat stress had no noticeable influence on the protein quality of the three wheat genotypes, measured using size exclusion high performance liquid chromatography (SE-HPLC). The durum variety had a better ratio of protein components and a significantly higher Zeleny value when exposed to heat stress, although it had the lowest grain yield and grain/straw ratio.The most significant negative correlation was observed between the Zeleny value and the unextractable polymeric protein (UPP%) fraction after heat treatment and between the relative protein content and the albumin+globulin % (AG%) in the case of drought. These correlations testify that these parameters play an important role in determining the baking quality of wheat flour.