부산대학교 도서관

Abstract: Two durum wheat (Triticum durum Desf.) cultivars (Simeto and Ofanto) were grown in field trials in Foggia (Southern Italy), under two water regimes and in three cropping seasons, to evaluate the influence of water regime on grain protein composition in relation to technological quality. On grain samples, the following quality analyses were performed: protein and gluten content, gluten index and SDS test. Furthermore, different protein fractions were evaluated: gliadins; glutenins, high molecular weight subunits (HMW-GS) and low molecular weight subunits (LMW-GS) of the larger glutenin polymers; percentage of unextractable polymeric proteins (%UPP). Two-dimensional gel electrophoresis (2D) of glutenins was also performed on selected samples. A year-on-year variation in gluten index was observed and its values were positively correlated (r =0.71**) with the number of days with maximum temperature ranging from 30 to 35°C during grain filling. This was consistent with an increase in glutenin fractions. Between the investigated cultivars, Simeto showed better technological performance and higher glutenin content, HMW-GS/LMW-GS ratio and %UPP. Water deficit was found to affect technological quality and protein composition differently depending on the timing of stress occurrence. An increase in protein content and in HMW-GS/LMW-GS ratio, consistent with a decrease in grain yield, was observed when water deficit occurred throughout the growing season. When a terminal water stress occurred in grain filling an improvement in gluten strength was observed consistently with an increase in the amount of glutenin macropolymers associated to a general modulation of HMW-GS and LMW-GS levels, as indicated by 2D analyses. Probably water deficit associated to high temperature stress which generally occurs under Mediterranean environments during grain filling, may have caused a higher aggregation level of glutenin subunits that was reflected in an improvement of technological quality. [Copyright &y& Elsevier]