The proper and sustainable management of nitrogen fertilization is one of the most common problems of cereal cultivation in semiarid regions, which are characterized by a wide variability in climatic conditions. The current work was conducted to evaluate the effects of nitrogen fertilization on the agronomic and economic aspects of durum wheat cultivated under rainfed semiarid conditions in Algeria and to determine the most efficient nitrogen use efficiency (NUE) among four genotypes that are widespread in the country (tall and short, old and modern genotypes). The four genotypes, Bousselam, MBB, Megress, and GTAdur, were investigated under four nitrogen rates from 0 to 120 kg N ha−1 during three cropping seasons (2016 to 2018). The results indicate that the total nitrogen uptake at maturity (NM), nitrogen uptake by grain (NG), nitrogen harvest index (NHI), NUE and its components, such as nitrogen uptake efficiency (NUpE) and nitrogen utilization efficiency (NUtE), were significantly affected by year, genotype, and nitrogen level. From this study, it appears that higher nitrogen rates improved NM and NG. However, no effects on either grain yield or marginal net return (MNR) were observed; conversely, increased nitrogen levels produced a 13% reduction in the economic return. In other words, in the North African environment, the response to nitrogen is more evident in quality than in yield, which in turn is dependent on the yearly weather conditions and cultivated genotypes. Moreover, nitrogen negatively affected NUE and its components (NUpE, NUtE). On average, NUE displayed low values (14.77 kg kg−1), mostly irregular and highly dependent on weather conditions; in the best year, it did not exceed 60% (19.87 kg kg−1) of the global average value of 33 kg kg−1. Moreover, the modern genotypes Megress (tall) and GTAdur (short) showed the best capacity to tolerate different nitrogen conditions and water shortages, providing relatively superior yields, as well as more effective N use from fertilizers and the soil than the other two genotypes.
Conductive flexible polypyrrole-silver (PPy-Ag) composite films were prepared on Biaxial Oriented Polyethylene Terephthalate (BOPET) substrate with surfaces treated by (3-aminopropyl) trimethoxysilane (APTMS). The surface treatment was carried out to improve the adhesion, morphology, and electrical properties of the deposited film to enhance the Electromagnetic Interference Shielding Effectiveness (EMI-SE). APTMS grafting on the BOPET substrate was confirmed by X-ray Photoelectron Spectroscopy (XPS) and Atomic Force Microscopy (AFM) analyses. All structural, morphological, and electrical features of PPy-Ag raised from different AgNO 3 molar ratio were investigated. The shielding effectiveness properties, experimentally determined for the synthesized PPy-Ag films were compared to those simulated analytically and numerically based on the transmission line matrix method (TLM). Both analytical and numerical models showed a good agreement with experimental measurements. The obtained results confirmed that the PPy-Ag films of 0.5 M/1 M molar ratio exhibits high EMI shielding performance of about 21 dB along with an electrical conductivity of 47 S/cm. Therefore, the treated surface flexible PPy-Ag films can be considered as potential candidate for high frequency electromagnetic interference shielding applications.
This article aims to provide a review of major challenges and research needs for the diffusion of conservation agriculture (CA) and the improvement of crop–soil–water conditions in Southern Europe and Northern Africa. A multidisciplinary study and a participatory approach are at the basis of an international project of research and innovation action, “Research-based participatory approaches for adopting conservation agriculture in the Mediterranean Area-CAMA”. It aims to understand the reasons and the research needs that limit a large CA diffusion in the Mediterranean countries. CAMA aims to provide significant advances to CA through multidisciplinary research at the field and farm scales (with main emphasis on smallholder), encompassing a socio-economic analysis of the reasons that obstacle the CA diffusion, legume crop improvement as a component of improved CA cropping systems, and a network of long-term experiments on CA and soil characteristic modification. Its results will be available to scientific and farming communities.
This study aimed to highlight the Citrus clementina nutritional quality leaves significance on infestations distribution of the citrus leaf-miner Phyllocnistis citrella Stainton (Lepidoptera; Gracillariidae). For each plant phenological cycle, infestation rates of P. citrella , carbon, nitrogen and phenolic compounds (CPT) were determined from collected leaves. The findings of P. citrella infestations show saved spring shoots, severely attacked autumn and summer leaves, and progressive infestations on additional leaves. Also, results revealed lower content of carbon in spring leaves as compared to additional, summer and autumn ones. In contrary, nitrogen was found to be higher in spring leaves. Summer and spring leaves contain, relatively, significant levels of total phenolic compounds. C/N balances seem to be substantial in summer, followed by additional and then spring and autumn leaves. Separately, infestations are negatively correlated with C and N accumulations, and positively with CPT and C/N. These ingredients are the main components of plant sap used by phytophagous sucking bugs. Herein, P. citrella infestation depends on the balance between nutritional (C and N) and deterrent (CPT) components. Effectively, as compared to the first cycle, P. citrella activates when the sap has nutrient-rich levels (especially carbon) and suitable C/N balance, despite the high level of diluted phenolic compounds in the mixture (SmS and AuS). This is clearly observed on additional shoots; less deterrents and abundance of nutritional nutrients. Remove additional shoots, as soon as they appear, can be a promising strategy of control, and obviously reduce P. citrella adults spread on summer shoots.
Crenate broomrape (Orobanche crenata Forsk.) is a serious long-standing parasitic weed problem in Algeria, mainly affecting legumes but also vegetable crops. Unresolved questions for parasitic weeds revolve around the extent to which these plants undergo local adaptation, especially with respect to host specialization, which would be expected to be a strong selective factor for obligate parasitic plants. In the present study, the genotyping-by-sequencing (GBS) approach was used to analyze genetic diversity and population structure of 10 Northern Algerian O. crenata populations with different geographical origins and host species (faba bean, pea, chickpea, carrot, and tomato). In total, 8004 high-quality single-nucleotide polymorphisms (5% missingness) were obtained and used across the study. Genetic diversity and relationships of 95 individuals from 10 populations were studied using model-based ancestry analysis, principal components analysis, discriminant analysis of principal components, and phylogeny approaches. The genetic differentiation (F ST) between pairs of populations was lower between adjacent populations and higher between geographically separated ones, but no support was found for isolation by distance. Further analyses identified four genetic clusters and revealed evidence of structuring among populations and, although confounded with location, among hosts. In the clearest example, O. crenata growing on pea had a SNP profile that was distinct from other host/location combinations. These results illustrate the importance and potential of GBS to reveal the dynamics of parasitic weed dispersal and population structure.
Clustering methods based on environmental variables are useful in the planning of conservation strategies for species and ecosystems. However, there is a lack of work on the regionalization of the vast space of North Africa and the distribution of plant species. The current lists of endemic plants are focused mostly on an occurrence at the country level and not on regions with different conditions. The aim of this work was to lay out an environmental scheme for northwest Africa and to collect data about the occurrence of endemic plants in this area. Clustering with 12 of 33 tested environmental rasters was performed to divide the Maghreb into environmental clusters. Then, a list of 1618 endemic plant taxa (1243 species and 375 subspecies) was prepared and their distribution in estimated environmental clusters was examined. Eleven clusters with different conditions were estimated. The main drivers of regionalization were temperature amplitude, precipitation seasonality, and precipitation of the warmest quarter. According to the occurrence of endemic plants, northwest Africa may be divided into three zones: Atlas, Mediterranean (two environmental clusters), and southern zone (eight environmental clusters). The presented results provide a good basis for understanding the spatial patterns of the Maghreb, including its environment and species diversity. A designed list of endemic plant species together with environmental data may facilitate the planning of future research in north Africa and arranging methods of biodiversity protection.
The sustainable protection of cedar stands in Chréa National Park can only be accomplished through stability of the ecosystem. Outbreaks of Thaumetopoea pityocampa are a major threat and largely attributed to the high population fecundity, changes in the diversity of natural enemies and global interactions within the ecosystem. Egg parasitoids (Hymenoptera) are essential in the biological control of T. pityocampa. To assess the impact of the parasitoids on the populations of the pine processionary moth, egg masses from cedar plantations were collected, reared in laboratory and checked regularly for the emergence of the egg-parasitoids: Trichogramma embryophagum, Baryscapus servadeii and Ooencyrtus pityocampa. Observations showed an inter-annual variation in the abundance of the three parasitoids as result of the variation in the population density of the processionary moth, and on the underlying effect of temperature. Parasitoids had variable parasitism rates, with yearly averages ranging from 3.86% to 51.14%, dependent on the spatiotemporal distribution of the host populations. The aggregate effect of multiple parasitoid species could optimize control of T. pityocampa in cedar stands.
Antibiotic residues in milk are a major health threat for the consumer and a hazard to the dairy industry, causing significant economic losses. This study aims to assess the presence of antibiotic residues in raw milk comparatively by a rapid screening test (BetaStar® Combo) and Liquid Chromatography coupled with Tandem Mass Spectrometry (LC-MS/MS). A total of 445 samples were collected from 3 dairy companies of north-central Algeria (Algiers, Blida, Boumerdes), and they were rapidly screened for β-lactams and tetracyclines; 52 samples, comprising 34 positive tanker-truck milk and 18 negative bulk-tank milk were tested by LC-MS/MS, which revealed 90.4% were contaminated (n = 47) and 55.3% exceeded the Maximum Residue Limit (MRL). The β-lactams as parent compounds and their metabolites were the most frequently detected with maximum value for cloxacillin (1231 µg/kg) and penicillin G (2062 µg/kg). Under field condition, the false-positive results, particularly for tetracyclines, seems to be related to milk samples displaying extreme acidity values (≥19°D) or fat-level fluctuations (2.7 g/100 mL and 5.6–6.2 g/100 mL). Despite a relatively low prevalence (7.64%) of residues using the rapid test, the detection by LC-MS/MS of flumequine (52 µg/kg), cefaclor (maximum 220 µg/kg) and metabolites of β-lactams at high levels should lead to reflections on the control of their human and environmental toxicological effects.
The objective of this study was to evaluate the effect of food supply in garbage dumps on the reproductive fitness of Cattle Egret Bubulcus ibis and offspring losses. A total of 236 nests were monitored during two distinct periods of 2 years for each: 146 nests during a period without food supply in dumps (1998–1999) and 90 with food supply in dumps (2007–2008). The study was carried out in the colony of El-Kseur in the Lower Soummam Valley (northeast Algeria). For the entire study period, the mean of clutch size, average number of hatched chicks, productivity, and breeding success varied significantly between years (Kruskal–Wallis test: p < .05). Also, the average calculated losses for eggs, chicks, and total offspring vary significantly (Chi2 test: p > .0001). The clutch size and the number of hatched chicks per nest were highest during the period with food supply in garbage dump (respectively: 3.46 ± 0.86; 2.85 ± 1.11), compared to the period when cattle egrets feed in natural or agricultural habitats (3.04 ± 0.87; 2.54 ± 1.03). However, productivity and breeding success were highest during the period without food supply (respectively: 2.11 ± 1.16 fledging’s/nest; 0.70 ± 0.35) than in the period with food supply (1.14 ± 0.91; 0.35 ± 0.30). While egg losses were substantially similar between the two study periods, chick’s mortality (59.9%) and total offspring losses (36.7%) were higher during the period with food supply. The generalized linear mixed model (GLMM) analysis indicated a large negative effect of food supply in dumps on the productivity, on the chick’s losses; and a positive effect on the total offspring losses (p < .001). Also, feed in dump garbage revealed a significant negative effect on the breeding success linear mixed model (LMM, p = .01). However, no significant effects (GLMM, p > .05) of food supply in dumps were noted on average clutch size, the mean number of hatched chicks per nest, and egg losses.
The influence of the drilling parameters and the stacking sequence of flax/epoxy composite laminate on the cutting force and the damage induced were studied experimentally and numerically. Drilling tests were carried out based on full experimental design and the delamination at the entry and exit of the hole were quantified using an optical microscopy. Moreover, the damages at the wall of the hole were analyzed using scanning electron microscopy. Based on the experimental results, it was observed that the drilling forces and the machining quality are influenced on the one side by the spindle speed and feed and on the other side by the stacking sequence composite plate. In fact, the cutting forces recorded when drilling a composite plate with [90/0/90/0] 2s is 30% higher to the one recorded when drilling a composite made with quasi-isotropic stacking sequence. A numerical model was developed in ABAQUS/Explicit using Hashin’s failure criteria in order to predict the cutting forces and the defects induced by the interaction of the drill and composite as a function of the machining parameters. The developed model has been validated at the macro-scale (thrust force) and the meso-scale (delamination at the entry and exit of the hole).
In recent decades, phytochemicals in plant extracts have been recognized as having insecticidal activity against insect pests. They have also been described as an alternative method to synthetic chemicals. The present study is a contribution on the insecticidal activity, under semi-natural conditions, of extracts of Nerium oleander L. on viviparous females of Chaitophorus leucomelas. Two extraction methods were performed with polar solvent to obtain two extracts used to carry out the insecticide tests. To identify the highest number of metabolites present in the plant three approaches were performed using supercritical fluid, ultrasound and enzymatic methods. Thirty-eight bioactive molecules were identified by GC/MS, some of which could be responsible for the insecticidal activity on viviparous females of C. leucomelas. The enzymatic extraction showed a very high monoterpene content of 34.62%, while the supercritical fluid extraction gave a content of 71.91% of oxygenated terpenic compounds. The results relating to the temporal estimation of insecticidal activity of the three studied concentrations of pure methanol and methanol-water extracts were found to be effective in terms of toxicity to viviparous females of C. leucomelas. A 100% mortality rate was observed 4 days after treatment at a concentration of 5.15g/m
Potato is one of the most important agricultural crops in Algeria and worldwide. Each year, potato late blight, caused by Phytophthora infestans, is responsible for significant damage that leads to large production losses, and is thus a direct threat to food security in Algeria. In this study, 131 isolates of P. infestans and 92 DNA fingerprints captured on FTA cards were sampled from commercial and seed production fields in three major potato production regions (western, eastern and central) during the main‐season and late‐season in Algeria over six seasons of cropping (2010˗2016). Genotypes of P. infestans and population genetic diversity were analyzed using a17‐plex simple sequence repeat (SSR) marker assay, and the mating type of all isolates was characterized. Both mating types (A1 and A2) were found, and often occurred in the same field. Differences in mating type proportion were observed between regions and between sampling periods. Analysis with SSR markers showed the prevalence of the EU_13_A2 lineage (70%) over EU_2_A1 (16%), EU_23_A1 (10%) and 4% were of unknown MLL. The EU_13_A2 showed differentiation within the group. EU_23_A1 was found mainly in late‐season crops. However, the cropping region did not influence the distribution of lineages due to the dispersal of the pathogen in Algeria by seeds. Genetic structure did not reveal a clear variation in distribution of the three lineages throughout the sampling regions. These data provide important new information on the composition and change over time of P. infestans populations in Algeria and open the way for a better understanding of the local epidemiology of this important pathogen.
Faba bean (Vicia faba L.) Algerian accessions represent an essential source of traits of interest for crop improvement, especially for tackling climate change, because their genetic background and potential have not been well studied. The purpose of this research was to assess the genetic variability of 14 Algerian faba bean accessions by means of 10 agro-morphological traits and 7 simple sequence repeat markers (SSRs). ANOVA analysis showed a large significant phenotypic variation in fruit setting (FS), seed length (SL), seed width (SW), and 100-seeds weight (HSW), which arose as the main discriminant characters as revealed by principal component analysis (PCA). In addition, SSR analysis identified a total of twenty different alleles within our collection with a mean of 2.85 alleles per locus. The polymorphism information content (PIC) ranged from 0.32 to 0.58, with a mean of 0.44. Observed heterozygosity (Ho) ranged from 0.57 to 1.00 with a mean of 0.72, while the expected one (He) varied from 0.42 to 0.67, reaching a mean of 0.57. Based on agro-morphological as well as molecular data, the 14 accessions were not clustered according to the geographical pattern, as also confirmed by principal coordinate analysis (PCoA). Moreover, AMOVA highlighted that most of the overall genetic variation within our collection was the result of strong differentiation among accessions (84%). Finally, the Mantel test revealed that there was no substantial correlation between the molecular and agro-morphological traits (r = −0.025, p > 0.05). These findings represent a first step toward faba been breeding programs establishment in Algeria, indicating that our collection exhibited optimal agro- and molecular diversity to identify specific traits useful in Mediterranean environment.
Seed priming with algae extracts is a promising alternative to stimulate growth, development and mitigate the harmful effects of salinity on plants. In the present study, we studied under a greenhouse, the effect of priming the seeds of bean (Vicia faba L.), with two concentrations (1% and 10%) of seaweed Ulva lactuca extract (SWE) and freshwater alga Spirogyra sp extract, on some physiological and biochemical parameters of the bean, under four salinity levels (0, 2, 8 and 32 dS/m). The results indicated that the use of SWE and freshwater alga extract has no significant effect on proline content, total soluble sugars content and electrolytes leakage, compared to untreated control, except for the salinity level S2 (8 dS/m) where the use of the freshwater alga extract at a concentration of 10% aggravated the leakage of electrolytes by 56% compared to the control. In non‐saline condition, chlorophyll pigments content showed no significant variation between plants from treated and untreated seeds, but under the highest salinity level S3 (32 dS/m) the chlorophyll pigment content was significantly improved by the use of SWE and freshwater alga extract. Overall under saline conditions, the priming in algae extracts seemed to have a positive effect on bean, which could account, at least in part, for the enhanced chlorophyll pigments content.
During 2016 and 2017, surveys for leaf diseases were conducted across several corn fields in Algiers (north) and Ghardaïa (south) regions, Algeria. Leaves samples exhibiting leaf spots were collected for recovering the potential fungal pathogens associated with the symptoms. Seventy isolates were recovered from the samples and characterized using phylogenetic, mor-phological, and pathogenic features. The isolates were morphologically grouped into two genera: Exserohilum and Bipolaris. Based on ITS, GAPDH, and RPB2 sequence data, Exserohilum isolates were identified as E. rostratumand E. monoceras, while Bipolaris isolates were identified as B. sorokiniana, B. microlaenae, and B. omanensis. Pathogenicity test was carried out under greenhouse conditions using the susceptible corn cultivars “Giza 352” and “Qing Qing300.” B. sorokiniana caused light green to grayish leaf spots with rounded or irregular margins (0.2–0.5 × 0.2–0.4mm); some lesions were circular to oval, white–gray with brown margins, surrounded by yellow-green halo (0.3–2.5 × 0.3–1.3mm). B. microlaenae induced grayish-white or light brown leaf spots, encircled by a reddish border (0.25–0.94 × 0.1–0.52mm). B. omanensis caused irregular, circular or oval necrotic spots, whitish gray in color and surrounded by a dark brown border (0.4–1.2 × 0.2–0.7mm). E. rostratum caused grayish brown lesions (0.2–5.0 × 0.2–1.5mm), which may develop to form tan to dark brown necrotic streaks. Finally, E. monoceras induced grayish or tan lesions (0.2–0.5 × 0.1–0.4mm), surrounded by yellow or orange halo. The lesions elongated parallel to the veins and may coalesce to form long gray streaks. To our knowledge, this is the first report of these five fungal species associated with corn leaf spots in Algeria. Furthermore, B. microlaenae and B. omanensis are recorded for the first time in the world as causal agents of leaf spot diseases in corn.
This study records the number of Peracarida (Cumacea, Isopoda, Mysida, Lophogastrida and Tanaidacea) from Algerian coastal waters. A total of 170 species are reported with the highest richness observed in the Isopoda (71 species), then the Cumacea with 43 species, the Mysida and Tanaidacea with 27 species each and the Lophogastrida with only two species. The diversity of Peracarida in Algeria is high, corresponding to 60% of the species recorded for the Mediterranean Sea. A geographical analysis of the distribution of the species shows that the Algerian fauna has a close similarity with taxa reported from both the European and African coasts of the Atlantic Ocean. This reflects the influence of Atlantic waters along the North African coasts extending from Morocco to Tunisia in the south of the Mediterranean Sea, which is related to the connection via the Strait of Gibraltar. For the Algerian coasts only five Peracarida species may be considered as Non-Indigenous Species.
Drought and low nitrogen are major stresses for maize (Zea mays L.), and maize populations from the Sahara Desert are potential sources of stress tolerance. The objectives were to assess the tolerance and varietal and heterosis effects of Algerian populations under no-nitrogen fertilization and water stress. A diallel among six Algerian maize population was evaluated under drought (300 mm irrigation) vs. control (600 mm) and no-nitrogen fertilization vs. 120 kh ha−1 N fertilization. Genotypes showed significant differences and genetic effects for water- and nitrogen-stress tolerance. We propose a reciprocal recurrent selection to take advantage of additive and non-additive effects, using AOR and IGS, since they showed good performance in optimum and stress conditions, for improving yield heterosis for AOR × IGS. Negative effects are not expected on plant height, anthesis–silking interval or early vigor. These populations and BAH could be sources of inbred lines tolerant to drought and no-nitrogen fertilization. There was no relationship between origin and genetic group and stress tolerance per se or as parents of tolerant crosses. These populations and crosses could be used as base material among Algerian populations, for breeding programs focusing on tolerance to water or nitrogen stress.
Les évolutions socioéconomique, démographique, politique et climatique que la steppe algérienne a connues au cours des dernières décennies ont induit de profondes transformations au niveau des pratiques d’élevage, tout particulièrement en matière de mobilités pastorales. Cette étude décrit de nouvelles pratiques de mobilité adoptées actuellement par des éleveurs de la région de Djelfa. Elle s’est basée sur 59 entretiens semi-directifs réalisés entre 2014 et 2016 auprès d’éleveurs dans différentes zones d’accueil. Nos résultats ont mis en évidence une diversité de pratiques pastorales relative à la distance parcourue durant un cycle annuel, au calendrier, à l’itinéraire de transhumance et au passage ou non par le terroir d’attache. Ces mobilités pouvaient varier d’une année à l’autre ou au cours de la vie d’un éleveur. Cette étude a montré que de nouvelles formes d’adaptation au contexte changeant de la steppe algérienne pouvaient être mises en oeuvre par les éleveurs par le moyen de nouvelles mobilités de grande distance. Nos résultats soulignent le renouvellement des formes de mobilité pastorale malgré le resserrement de l’espace et montrent que la sédentarisation n’est pas l’unique forme d’adaptation des populations pastorales aux changements.
Drought is the main constraint to maize production in the Mediterranean area. This is the first report of breeding temperate maize populations from the Algerian desert. The objective of this study was to evaluate response to selection for reduced anthesis-silking interval (ASI) in Algerian maize under drought and control conditions. Three cycles of selection for reduced ASI were carried out in four populations under control and drought conditions, and the breeding program was evaluated under both conditions. Selection under drought was more efficient than under control conditions , particularly for the LOM and TAO populations. Selection for low ASI reduced ASI and days per cycle for BTM and IGS, respectively, under drought conditions. Selection for ASI reduced an-thesis in BTM, when selected under drought and evaluated under control conditions. Significant yield increase was observed for BTM under optimal conditions. Significant genetic gain for yield was observed for the population LOM under drought. Therefore, the improved Algerian populations BTM and TAO could be a novel source for reducing ASI and for earlier flowering time as a mechanism for avoiding drought. Furthermore, we propose these populations as sources to develop tolerant inbred lines and to find quantitative trait loci for drought tolerance.
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