ABSTRACT: Environmental stress during grain filling may affect wheat protein composition, thus influencing its final quality. A proteomic approach was used to evaluate changes in storage protein composition under water stress of two Italian durum wheat (Triticum turgidum ssp. durum) cultivars, Ciccio and Svevo. The high-molecular-weight glutenin region increased progressively in both cultivars and under two water regimens. The L48−35 region, corresponding to low-molecular-weight (LMW) glutenin subunits, increased slightly during grain development and decreased under water stress in both cultivars. In particular, an s-type LMW related to superior technological quality was down-expressed in the early−mid period in Svevo and in the mid−late period in Ciccio. Finally, the L<35 region, corresponding to gliadin-like proteins, decreased slightly during grain development and increased under stress in both cultivars. Several α-gliadins, associated with immunological potential, increased their expression under water stress, especially in Svevo in the early−mid stage of grain filling.

Il presente capitolo tratta le tematiche connesse alla gestione sostenibile della risorsa idrica nei sistemi agricoli. Nella prima parte vengono fornite informazioni relative al bilancio idrico del suolo e agli interventi tecnici idonei a mantenere il giusto equilibrio tra le voci del bilancio per un uso efficiente sia della risorsa idrica che del suolo stesso. Nel trattare la voce del bilancio relativa al drenaggio, vengono illustrate le tecniche agronomiche utilizzate per assicurare lo smaltimento dell’acqua in eccesso attraverso gli impianti di drenaggio a fognatura, a dreni temporanei e tubolari, e i relativi benefici in termini agronomici e ambientali. Successivamente vengono descritti i principi di base della tecnica irrigua, finalizzata all’apporto artificiale di acqua alle colture in caso di carenza nel suolo. Vengono illustrate le principali variabili irrigue, la determinazione del momento dell’intervento e dei volumi di adacquamento e i metodi irrigui. Vengono inoltre descritte le più recenti tecniche finalizzate al risparmio e all’uso efficiente e sostenibile della risorsa idrica, considerando anche il tema della qualità delle acque per uso irriguo e delle tecniche di utilizzo delle acque non convenzionali. Il capitolo si conclude con l’illustrazione della risposta delle colture all’irrigazione, e dei criteri di programmazione irrigua in funzione della specie. Per una migliore comprensione degli argomenti trattati si consiglia lo studio propedeutico di quanto contenuto nei capitoli 2, 3 e 5.

In press

Durum wheat (Triticum durum Desf.) is widely cultivated in the Mediterranean area where plants generally suffer from water stress during grain-filling period. This study was conducted to evaluate the influence of N levels and water regimes on N translocation and nitrogen use efficiency for protein (NUEP) in durum wheat grown under Mediterranean conditions. A 2-yr experiment was performed in southern Italy using four cultivars, two water regimes (irrigated and rainfed) and three N levels (0, 60, and 120 kg ha–1). Among the cultivars under study, Simeto showed the highest N translocation in both years and, together with Ofanto, also the highest NUEP values, especially in rainfed condition. This highlights their good adaptability to dry Southern Italy environment. Nitrogen fertilization caused a general decrease of NUEP and its components in both growing seasons; this was more evident in the first drier year, mainly due to a decrease in N uptake. Under water stress the higher N level caused a decrease in N translocation, N translocation efficiency, and grain N content. The contribution of translocated N to grain N content was 75% in the wetter year and 57% in the drier year, showing that in drought condition preanthesis N assimilation was lower. In conclusion under water stress condition the higher N level (120 kg ha–1), despite determining an increase in plant N content, did not imply an increase in grain N content, due to a decrease in N translocation and efficiency.

The relationships between grain quality and N utilization in durum wheat (Triticum durum Desf.) have not been very thoroughly investigated. The aim of this study was to evaluate the effects of N fertilizer rate and water regime on grain yield and quality under Mediterranean conditions in relation to N utilization. Four durum wheat cultivars (Appio, Creso, Ofanto, and Simeto) were grown in field trials under two water regimes (irrigated and rainfed) at three N levels (0, 60, and 120 kg ha–1) in southern Italy during two cropping seasons. At harvest, grain yield and its main components, protein and gluten content, gluten index, sodium dodecyl sulfate sedimentation test, rheological indices dough strength alveograph index (W) and tenacity/extensibility ratio (P/L), and grain yellow index were determined. For the rainfed treatment in the first (drier) year, a decrease in grain yield consistent with an increase in protein content, gluten index, and W and P/L indices was observed. With increasing N level, protein content increased in both growing seasons but a significant improvement in technological parameters was observed only in the first year, mainly under rainfed conditions. Among the investigated cultivars, only Simeto always showed both good yield and quality performance. The positive correlation between plant N content at anthesis and protein content indicated a significant contribution of pre-anthesis assimilation. The high correlations found for both N translocation and N harvest index with technological indices suggest that lately remobilized N might increase the protein polymerization degree, with a consequent improvement in grain quality.