Do barley and wheat (bread and durum) differ in grain weight stability through seasons and water-nitrogen treatments in a Mediterranean location?

Under Mediterranean environments, farmers usually prefer to sow barley rather than wheat as it is generally believed that barley yields more under stressful conditions. As terminal stresses such as high temperature and water are common constraints in Mediterranean regions, higher grain weight stability may confer a clear advantage in order to maintain higher yields. The objective of the present study was to compare the stability in terms of grain weight and its components for barley, bread wheat, and durum wheat, exploring a wide range of nitrogen and water availabilities in experiments conducted in a Mediterranean region. Grain weight ranged from 23.8 to 47.7 mg grain⁻¹, being higher for durum wheat than barley and bread wheat. Durum wheat presented higher variability both in maximum grain filling rate and duration of grain filling period than bread wheat or barley. The three species responded similarly in terms of grain nitrogen content to changes in the environmental conditions explored. It is concluded that in terms of grain weight barley is as stable as bread wheat. However, durum wheat presented a lower stability than barley and bread wheat.     

Wheat productivity in the Mediterranean Ebro Valley: Analyzing the gap between attainable and potential yield with a simulation model

Water deficit is an important constraint for wheat yield generation under Mediterranean environments. However, nitrogen (N) availability could limit yield in a more important way than poor water conditions. The aim of the work was to analyze, using the Ceres-Wheat crop simulation model, to what degree N fertilization constitutes a tool for reducing the gap between attainable and potential yield. Firstly, the model was calibrated and validated under a wide range of N and water conditions for the region of the Ebro Valley (NE Spain). Anthesis and maturity date were adequately predicted by the model. Predictions of yield tended to be quite accurate in general, though under severe water deficits precision was lower. We then assessed the gap between attainable and potential yield considering different N availabilities at sowing taking into account a weather database of 17 years for the location of Agramunt (NE Spain), representative of cereal growing conditions of the Mediterranean Catalonia. Potential yield ranged between 3.5 and 8.1 Mg ha⁻¹. Variations in potential yield were explained by the duration of the period from sowing to anthesis and by the level of incident radiation during the period immediately previous to anthesis. Average attainable yield was 1.8 Mg ha⁻¹ for N availability of 50 kg_N ha⁻¹; but increased to 2.8 Mg ha⁻¹ for higher N availabilities (100–250 kg_N ha⁻¹). In the 25% of the worst years there was no effect of N availability on attainable yield. Increasing N availability beyond 100 kg_N ha⁻¹ generated a gain in yield only in 6% of the years. Variations between years in attainable yields were mainly explained by rainfall during the period from sowing to anthesis, whereas differences in attainable yield between N treatments increased with increases in rainfall. The gap between potential yield and attainable yield was higher in years with higher potential yield. On the other hand, the higher the attainable yield, the lower the gap. Thus, the proportion of the yield gap ascribed to N availability varied depending on the conditions of the growing season. In the high-yielding potential years, the main restriction for growth was water shortage, and fertilizing only slightly reduced the gap. Conversely, in rainy years characterized by low potential yields and mild water stresses, N management may constitute a simple tool for effectively reducing yield gap under rain-fed conditions.     

Evaluation of Liquid Nitrogen Freeze Drying and Ethanol Dehydration as Methods to Preserve Partially Cooked Starch and Masa Systems

Preservation of starch structure/properties, including structures formed during partial or complete cooking, are important when the impact of processing conditions is being studied. Two preservation techniques used to study changes in starch during thermal‐mechanical processing are commonly cited in the literature: 1) rapid freezing followed by lyophilization, and 2) a dehydration procedure using alcohols. A comparative determination on how these methods affect various starch structures has not been widely reported. Corn starch samples were collected from the Rapid Visco‐Analyser (RVA) at 3 min (swollen granules, 30°C), at the top of the pasting peak (gelatinized granules, 95°C), at the bottom of the trough (dispersed polymers, 95°C), and a completed RVA sample stored for 120 hr at 4°C (retrograded starch). Samples of masa were obtained by nixtamalizing corn. Differential scanning calorimetry (DSC) endotherms of starch and masa, and X‐ray diffraction (XRD) patterns of masa were evaluated after being preserved by alcohol‐ or freeze‐drying. No significant differences (P > 0.05) between methods were found for onset, end, and peak temperatures (°C), enthalpy (J/g) and % relative crystallinity in any of the samples analyzed. Liquid nitrogen freeze‐drying and ethanol dehydration are both effective methods of preserving various starch systems for structural changes detectible by DSC and XRD; freeze‐drying is generally less expensive and time‐consuming.     

Evaluation of the cytotoxicity, genotoxicity, mutagenicity, and antimutagenicity of propolis from Tucuman, Argentina

This study evaluates the toxic, genotoxic/mutagenic, and antimutagenic effects of propolis extract from Amaicha del Valle, Tucumán, Argentina. The cytotoxicity assays carried out with the lethality test of Artemia salina revealed that the LD50 was around 100 microg/mL. Propolis extracts showed no toxicity to Salmonella typhimurium TA98 and TA100 strains and Allium cepa at concentrations that have antibiotic and antioxidant activities. Otherwise, for the testing doses, neither genotoxicity nor mutagenicity was found in any sample. The propolis extracts were able to inhibit the mutagenesis of isoquinoline (IQ) and 4-nitro o-phenylenediamine (NPD) with ID50 values of 40 and 20 microg/plate, respectively. From this result, the studied propolis may be inferred to contain some chemical compounds capable of inhibiting the mutagenicity of direct-acting and indirect-acting mutagens. A compound isolated from Amaicha del Valle propolis, 2',4'-dihydroxychalcone, showed cytotoxic activity (LC50 values of 0.5 microg/mL) but was not genotoxic or mutagenic. Furthermore, this compound was able to inhibit the mutagenicity of IQ (ID50 values of 1 microg/plate) but was unable to inhibit the mutagenicity of NPD. Our results suggest a potential anticarcinogenic activity of Amaicha del Valle propolis and the chalcone isolated from it.     

Assessment of quality characteristics of new Vitis vinifera L. cultivars for temperate climate vineyards

Since quality requirements for table grapes are mainly related to their physico-chemical and mechanical features, the aim of this work was to provide useful data for grape producers and consumers concerning the quality characteristics of table grapes of five new Vitis vinifera L. cultivars created in Romania and tending to spread within the temperate climate vineyards. During grape maturation, sugar content increased in a lesser extent than the reducing of total acidity, a balanced taste of grapes was given by the decrease in total acidity rather than sugar accumulation. Grapes of analysed cultivars showed lower concentrations of ascorbic acid and a higher content of organic nitrogenous compound. Berries with higher weight and volume (Transilvania cv.) incurred a higher mechanical deformation, while long berries (Gelu cv.) showed higher resistance to detachment from the pedicel, indicating higher resistance of grapes to packing, transport and storage. Antioxidant activity of mature grapes was high, but involvement of nonflavonoids in increasing the antioxidant capacity was statistically non-significant. Seeded table grapes of new Vitis vinifera L. cultivars showed superior physico-chemical and mechanical characteristics, indicating their high quality in the conditions of temperate continental climate, and promoting the studied cultivars as important grapevine germplasm resources.