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Plant performance is strongly dependent on nitrogen (N), and thus increasing N nutrition is of great relevance for the productivity of agroecosystems. The effects of arbuscular mycorrhizal (AM) fungi on plant N acquisition are debated because contradictory results have been reported. Using 15N-labeled fertilizers as a tracer, we evaluated the effects of AM fungi on N uptake and recovery from mineral or organic sources in durum wheat. Under sufficient N availability, AM fungi had no effects on plant biomass but increased N concentrations in plant tissue, plant N uptake, and total N recovered from the fertilizer. In N-deficient soil, AM fungi led to decreased aboveground biomass, which suggests that plants and AM fungi may have competed for N. When the organic source had a low carbon-to-nitrogen ratio, AM fungi favored both plant N uptake and N recovery. In contrast, when the organic source had a high carbon-to-nitrogen ratio, a clear reduction in N recovery from the fertilizer was observed. Overall, the results indicate an active role of arbuscular mycorrhizae in favoring plant N-related traits when N is not a limiting factor and show that these fungi help in N recovery from the fertilizer. These results hold great potential for increasing the sustainability of durum wheat production.

Debranning was applied to durum wheat to the study the relationship between kernel shape and size, and ash and mineral distribution having implications for semolina yield. To this aim four durum wheat genotypes carried out over three environments were selected to determine the morphological and yield traits as well as the distribution along the kernel of the ash, macro- (Na, K, P, Ca, and Mg), and micro-elements (Mn, Fe, Cu, Zn, and Mo). A descendent ash gradient within the kernel reflects the decreases in the minerals that occurred during debranning. Perciasacchi with high seed weight (TKW) and greater thickness followed by Cappelli showed a more uniform distribution of ash content along the kernels. High r Pearson coefficient (p &lt, 0.01) showed an inverse relationship between thickness and ash decay. Since thickness was strongly affected by the genotype, it could represent a useful trait for breeding programs to predict the milling quality.

Determining the best conservation agriculture practices for increasing soil organic carbon (C) and hence soil quality is of paramount importance in the semi-arid Mediterranean environment, where soils are experiencing a continuous decline in organic matter. Therefore, the aim of this long-term study was to assess the combined effects of tillage system and crop sequence on soil organic C and biochemical properties of soil generally used as indicators of soil quality. After 23 years of continuous application of contrasting tillage systems (conventional tillage [CT], vs. no tillage [NT]) and crop sequences (wheat monoculture vs. wheat-faba bean rotation), soil samples were collected from topsoil (0–15 cm) and subsoil (15–30 cm) at three different times during a cropping year. Soil samples were analyzed for total and labile organic C pools, microbial biomass C (MBC) and microbial biomass N, basal respiration, and the abundance of main microbial groups by phospholipid fatty acids. Long-term NT increased total organic C (TOC) at a yearly rate of 0.17 g kg−1. This in turn stimulated microbial biomass, in particular Gram-negative bacteria. This suggests a higher soil quality in NT, as was confirmed by the increase in MBC/TOC and the decrease in stress indices. In contrast, no differences were observed with regard to fungal biomass. These findings suggest the need to reconsider the role of specific bacterial groups in organic C accumulation in soils of semiarid environments. It is interesting that the effects of long-term NT varied widely by crop sequence, whereas in CT changes in biochemical characteristics and in the main microbial groups due to crop sequence were modest. Thus, the interaction among various aspects of agronomic management modulates the effects of substrate quality on chemical and biological properties of soil.

Several studies showed that products made with ancient wheat genotypes have beneficial health properties compared to those obtained with modern wheat varieties, even though the mechanisms responsible for the positive effects are not clear. Ancient durum wheat genotypes are being currently used for the production of pasta, bread and other typical bakery products but the consumption is strictly local. In this work 15 genotypes of Triticum turgidum subsp. durum, including 10 ancient and 5 modern, were characterized for their technological traits through the determination of different parameters: protein content, dry gluten, gluten index, yellow index, ash, P/L, W and G. In addition, the baking aptitude of all genotypes was evaluated. All semolinas were subjected to leavening by commercial baker’s yeast and the experimental breads were subjected to the qualitative characterization (weight loss, height, firmness, colour, volatile organic compounds, image and sensory analysis). The results obtained showed that protein content of grains and semolinas was higher in ancient rather than modern genotypes. Dry gluten ranged from 6.7% of the modern variety Simeto to 13.6% of the ancient genotype Scorsonera. Great differences were found for the yellow index which reached the highest value in Saragolla variety. The P/L and W ratios were significantly higher for the modern genotypes. On average, weight loss was about 14 g, while bread height varied significantly between the trials. Bread consistency varied between 12.6 and 31.3 N. Differences were observed for the yellow of the crumb (higher for modern genotypes) and for the redness of the crust (higher for ancient genotypes). The sensory evaluation displayed a high variability among the breads from the 10 ancient genotypes, while the control breads received scores closed to those of the modern genotypes. This study revealed that the modern durum wheat varieties showed a certain uniformity of behaviour, while the ancient genotypes exhibited a great variability of the final attributes of breads.