Durum Wheat Quality, Yield and Sanitary Status under Conservation Agriculture

In Mediterranean environments the adoption of Conservation Agriculture (CA) would allow growers to achieve environmental, agronomic and economic sustainability. We investigated the effect of different combination of crop establishment treatments and crop sequence (conventional tillage (CT) and durum wheat monocropping (WW); conventional tillage (CT) and durum wheat following faba beans (WF); zero tillage (ZT) and durum wheat monocropping (WW); zero tillage (ZF) and durum wheat following faba beans (WF) on yield, grain quality traits as well as on disease incidence and severity in durum wheat (var. Saragolla). The results of two years of data of a long-term experiment (seven-year experiment; split-plot design) are discussed. The CA approach (ZT + WF), which always induced the highest grain yields (6.1 t ha-1 and 3.3 t ha-1 in 2016 and 2017) thanks to an increased number of spikes m-2 (296 vs. 269 and 303 vs. 287 spikes m-2 in 2016 and 2017, respectively) as well as a more pronounced ear length, demonstrated significantly positive influences in terms of grain quality. It promoted grain protein accumulation (12.1% for ZT + WF vs. 11.4% for ZT +WWand 12.4% for ZT + WF vs. 10.6% for ZT +WWin 2016 and 2017) and improved the gluten quality (in terms of sodium dodecyl sulphate (SDS) sedimentation test) and colour of the grain. The abundance of crop residues determined a higher incidence and severity of Zymoseptoria tritici leaf symptoms under the CA system; nevertheless, the late appearance of infection was the main reason for not affecting yield and quality traits. The presence of faba beans (WF) in the rotation significantly reduced leaf symptoms in Z. tritici.