Conservation agriculture (CA) is seen as a key strategy for improving the sustainability of agriculture while being resilient to the climatic hazards due to climate change. Tunisia, which introduced CA since 1999, is struggling to develop this practice on a large scale due to the lack of commitment on the part of farmers, who need tangible results to adopt this tillage method. This study investigates the effects of rainfall variations on the active vegetation period and yield of durum-wheat, and the resilience of CA in the semi-arid rainfed regions of northwestern Tunisia. The analysis reveals significant rainfall variability, with fluctuations of 40

Managing tillage intensity and diversifying crop rotation are important sustainability levers for conservation agriculture (CA) with the potential to enhance crop resilience, resource efficiency, and yield stability. Accordingly, this study aimed to determine the effect of reduced tillage intensities and cereal-legume rotation systems on the agronomic and physiological performance of rainfed durum wheat grown under Mediterranean semi-arid conditions. To this end, a two cropping seasons field experiment was conducted in northeast Tunisia where the combined effects of two reduced tillage intensities (minimum and no-tillage; MT and NT) and two legume-based crop rotation systems (biennial and triennial; B and T) were compared to the more traditional conventionally tilled monocropping system (CT and M). Crop rotation, particularly when integrated with no-tillage (NT), significantly improved wheat development and grain yield, along with key yield attributes such as thousand-kernel weight and spike density. The interaction between tillage and crop sequence was highly influential; for instance, the NT & times; T (no-tillage & times; triennial rotation) combination achieved the highest grain yields (240 and 236 g m-2 in 2020-2021 and 2021-2022, respectively), while the CT & times; M (conventional tillage & times; monoculture) interaction resulted in the lowest productivity (143 and 135 g m-2). Physiologically, the integration of reduced tillage and legume-cereal rotations optimized the photosynthetic apparatus, as evidenced by significantly improved chlorophyll fluorescence parameters. However, a prominent trade-off was identified: while NT & times; T maximized productivity, conventional tillage (CT) maintained superior grain protein (18.6%) and gluten concentrations, indicating a nitrogen dilution effect in high-yielding conservation systems. These results demonstrate that while no-tillage and triennial rotations (faba bean-wheat-barley) are robust strategies for climate-resilient yields in semi-arid environments, they must be coupled with optimized nitrogen management to offset quality declines. Consequently, this study establishes the NT & times; T interaction as a superior model for sustainable rainfed farming, provided that nutrient synchronization is addressed to ensure nutritional security under increasingly unpredictable Mediterranean climates.

This study aimed to evaluate the resilience of two barley varieties (‘Ardhaoui’ and ‘Manel’) to thermo-hydric stress under conservation agriculture (CA) compared to conventional agriculture, across different sowing dates (normal, late) and water regimes (rainfed, irrigated). Field experiments were conducted during the 2020–2021 winter growing season at a representative semi-arid site in Western Tunisia, and climatic trends over the past 24 years were analyzed to contextualize current stress conditions. A severe water deficit, coupled with a rise in temperature and increased ET0, occurred during grain filling. This tendency towards climate change is confirmed by the site's climatic characterization over 24 years, during which temperatures have risen by 0.16 °C per year (r = 0.800, p = 0.01). Results showed that CA significantly improved barley performance, increasing biological and grain yields by 26% and 29%, respectively, suggesting more efficient rainfall utilization. Supplemental irrigation further enhanced grain yield (51%) relative to biological yield (45%). The local variety ‘Ardhaoui’ demonstrated higher tolerance to drought and heat stress than the improved variety ‘Manel’. Biomass was more sensitive to heat stress than grain yield (32% vs. 24%), indicating a potential shift in harvest index under extreme conditions. Stress tolerance indices (HSTI and STI) and phenolic compound analysis confirmed that CA and supplemental irrigation mitigated the negative effects of thermo-hydric stress. The significant positive interaction (p = 0.001) between tillage method and sowing date confirms that tillage practices alleviate heat stress expression. These findings highlight that CA, when combined with appropriate variety selection and irrigation management, can improve barley resilience under semi-arid conditions. The study also underscores the importance of local varieties in adapting to climate variability, while cautioning that results are based on a single season and site, and multi-year evaluations are needed to confirm long-term benefits.

Adopting climate-smart agriculture innovations, such as Conservation Agriculture (CA), is necessary in Tunisia to mitigate the impacts of climate change. The present study assessed the impact of CA on the resilience of durum wheat yield and water use efficiency (WUE) in the context of current climate change. The study involved a comparison of durum wheat yield stability and resilience over 12 successive years (from 2010 to 2022), between no-till (NT), minimum tillage (MT), and conventional tillage (CT), as influenced by precipitation and temperature variations across the crop cycle and year. The effect of tillage treatments on phenological stages (days to heading and grain filling duration) and soil organic carbon and nitrogen were assessed. Weather variables analysis revealed a significant decrease in precipitation and a significant increase in the number of rain-free days and temperature over the years. Results showed that durum wheat yield and aboveground biomass decreased over time in all three tillage treatments, but the rate of grain yield decreased differed significantly between the treatments. NT showed the smallest decrease rate in yield, followed by MT and CT, as well as the smallest coefficient of variation, indicating better yield stability. A highly significant relationship between weather variables and yield response ratios was observed, where the NT-to-CT ratio increased as precipitation decreased. Analysis of yields, soil water content, and phenology revealed that NT did not significantly outperform CT across all experimental years but showed a significant advantage only during years with low precipitation. Analysis of the relationships between variability in yield and variability in weather variables revealed that the NT system was less sensitive (more resilient) to changes in weather variables, especially with regard to the autumn and late spring precipitations. This is of great importance in emphasizing the necessity of the adoption of NT. The study demonstrated that the benefits of CA are particularly pronounced in years with extreme drought events, highlighting the importance of adopting such agriculture innovation to mitigate the impacts of changes in weather variables on durum wheat yield.

Water is the most limiting factor of crop production in semi-arid areas. In this way, Conservation Agriculture (CA) based on direct seeding has been proposed as a promising strategy for improving soil quality and water use. As part of the CA-Maghreb project, a field experiment was carried out during the 2017–2018 crop-ping season in the El-Krib region of North-Western Tunisia. The experiment studied the agronomic performances and water use efficiency (WUE) of two durum wheat cultivars (“Maali” and “Hadhba”), conducted in direct seeding under living plant cover (DSLC) and direct seeding under dead plant cover (DSDC). Results showed that the “Hadhba” cultivar recorded the highest cumulative total dry matter rate when grown in DSLC, with 1.04 kg m−2 compared to the “Maali” variety, which recorded 0.59 kg m−2. The highest grain yields were obtained when durum wheat was grown in DSDC (0.17 and 0.16 kg m−2) for “Hadhba” and “Maali”, respectively. The highest WUE was recorded for the “Hadhba” cultivar, with an improvement in WUE for dry matter production in DSLC (3.21 kg m−3) compared to sowing under dead cover (2.69 kg m−3). Based on these results, the DSLC package constitutes a potential sustainable pathway to improved water resource use and crop yields. However, direct seeding under plant cover alone is not enough to obtain higher yield productivity. Complementary practices, such as crop rotation and residue management, are required to be included to make CA systems more functional in the short and long term.

Conservation agriculture (CA) has been proposed as a viable strategy to enhance soil health and the resilience of farms to climate change, and to support the sustainability of agricultural production systems. While CA is a well-established approach, research results are lacking regarding its long-term impact on nitrogen (N) dynamics in the soil–plant system. In this study, a 20-year experiment was used to investigate the long-term effects of no-tillage in CA on soil organic carbon (SOC) and nitrogen (N) mineralization, plant N uptake, grain yields, and the grain quality of durum wheat. A CA system based on no-tillage (NT) was evaluated and compared with conventional tillage (CT) used for wheat/legumes biennial crop rotation. Results showed that soil samples from CA plots experienced significantly more N mineralization than those under CT, which was attributed to increased SOC and N. Topsoil sampled from the CA plots 20 years after the implementation of the experiment had 43% more absolute potentially mineralizable N (N0) than the CT plots, with no significant differences observed in deeper soil layers (15–30 cm and 30–45 cm). The absolute potentially mineralizable carbon (C0) in soils from the CA system was 49% and 35% higher than in soils from the CT system, at soil depths of 0–15 and 15–30 cm, respectively. Furthermore, CA resulted in higher amounts of remobilized N and higher rates of N uptake during the critical growth stages of durum wheat. The amount of N remobilized during the kernel-filling phase under CA was 59% higher than under CT. Total N uptake in wheat plants was 45% greater under CA compared to CT. The most significant differences in N uptake between the CA and CT systems were observed during two critical growth stages: late tillering to heading (1.7 times higher in CA than CT) and heading to anthesis (1.5 times higher in CA than CT). The most significant differences for N uptake were shown during the late tillering to heading stage and the heading to anthesis stage. The amount of N remobilized during the kernel filling phase under CA was 59% higher than CT. CA adoption resulted in 21% and 35% higher grain and straw yields, respectively, compared to CT. The grain and straw N yields were 21% and 51% higher, respectively, under CA than CT. Moreover, the CA system exhibited higher partial factor productivity of nitrogen fertilizer (PFP N) for both grain and straw yields. Thousand kernel weight (TKW) and hectoliter weight were also significantly higher under CA than CT. The grain protein content, wet gluten content, vitreousness, and falling number were similar between the CA and CT systems. These results highlight the benefits of long-term CA adoption to increase soil N mineralization, providing a substantial base for N uptake during the critical growth stages of durum wheat, thus leading to increased crop yield. The findings underscore the potential of CA systems in promoting sustainable agriculture and mitigating the impacts of soil degradation.

This work aims to enhance our understanding of plant-defense mechanisms, which is crucial for developing resistant crops following pest attacks. Focusing on the susceptibility of Tunisian barley to the gall midge Mayetiola hordei, the current study explores how gall formation affects the structure of attacked organs, and how sensitive and resistant barley cultivars respond to infestations. Two barley cultivars, Kounouz and Rihane, were selected for this experiment in two semi-arid regions of North Tunisia, Zaghouan and Kef. Sampling was carried out at four stages of barley development (tillering, elongation, heading, and ripening). Kef region was identified as the most affected area, recording significant economic and severe infestations for Kounouz variety, particularly at the ripening stage (53

Conservation agriculture based on no-tillage (NT) and crop rotation allows to enhance soil health. Based on data collected from long-term trials in a semi-arid region of Tunisia, results showed that NT increased significantly soil organic carbon stock (SOCS), soil microbial biomass carbon (SMBC), arbuscular mycorrhizal fungal (AMF) root colonization, and soil microbial respiration (CO2) at 0–20 cm topsoil layer compared to conventional tillage (CT). Moreover, triennial rotation (TRI), based on annual succession of Faba bean-Durum wheat-Barley, and biennial rotation (BI), based on annual succession of Faba bean-Durum wheat, increased significatively SMBC, AMF, and CO2. Likewise, a significant benefit of the two-way interactions Tillage × Rotation was observed. Furthermore, NT combined with TRI recorded the highest SOCS (2181 g C m−2), SMBC (515 mg C kg−1 soil), AMF (14%), and CO2 which is an indicator of soil microbial respiration (1071 mg CO2 kg−1 soil). The current results highlight the benefit adoption of minimum or (NT)combined with crop diversification on soil health.

A three years survey and monitoring studies (2013-2014-2015) were carried out through 4 regions of north Tunisia in order to follow the evolution of the distribution, the frequency of occurrence and damage caused by the Hessian fly Mayetiola destructor (Say) to bread wheat (Triticum aestivum L.) and durum wheat (Triticum durum Desf). Moreover, the effectiveness of resistance genes H3, H5, H6, H7, H8, H9, H10, H11, H12, H13, H14, H15, H22, H23, H25 and H26 to protect wheat from Hessian fly attack was assessed in natural field and under controlled laboratory conditions at INRAT-Kef Station. Results showed that Hessian fly was detected in 60.33% and 51.5% of all sampled durum and bread wheat fields, respectively. This pest was more frequent with a higher percentage of infestation in semi-arid regions. Indeed, during 2013, infestation rate attained 12.39% in Kef region against 0.9% registered in Bizerte region. In order to update information about the annual number of generations, we surveyed the population dynamic of Hessian fly in Kef region. Three generations of the fly were counted annually on wheat, with two complete and one incomplete generation. This insect affects host plant growth at different developmental stages. Plant height was the most affected parameter followed by shoot dry weight and tiller number. Field investigations on host resistance revealed that among the 16 tested resistance genes, and only three were strictly effective (H22, H25 and H26). The resistance genes H5, H9, H13 and H9H13 have also conferred high levels of protection against Hessian fly. This work indicated that H22, H25 and H26 genes could be incorporated into Tunisian wheat varieties and released to farmers to manage the threat due to Hessian fly attacks.

In order to establish the optimal level of irrigation and seeding rate to achieve high grain yield and water use efficiency (WUE) for durum wheat (Triticum durum Desf.) in a Tunisian semi-arid region, three durum wheat varieties (Maâli, Nasr and Chili) were evaluated under four levels of irrigation (I3: 70% of field capacity (FC); I2: 40% FC; I1: 10% FC; I0: rainfall) and five seeding rates (D1: 250, D2: 300, D3: 350, D4: 400, D5: 450 seeds/m 2 ). The level of irrigation significantly affected all traits except for 1000-kernel weight. I3 induced maximum grain yield (GY) (106.7 q/ha), number of spikes/m (607.8), number of kernels/spike (51.09), 1000-kernel weight (50.45 g) and biomass yield (BY) (349 q/ha) while the rainfed treatment (I0) showed the lowest values. GY and BY were positively correlated (r = 0.6) with number of spikes/m. Highest WUE of grain yield (WUEg) and of biomass yield (WUEb) were observed under moderate irrigation (I2) and exceeded values obtained under the highest water regime (I3) by 11.08% and 7.9%, respectively. Seeding rate D3 showed lowest mean values of GY (71.10 q/ha), BY (238 q/ha), WUEg (1.49 kg/m) and WUEb (4.96 kg/m). WUEg was positively correlated to harvest index (r = 0.45).The WUEg and GY of Maâli (91.63 q/ha) were significantly higher than those of Nasr (83.88 q/ha) and Chili (66.16 q/ha). However, Chili had Original Research Article Othmani et al.; AJORIB, 2(2): 30-39, 2020; Article no.AJORIB.319 31 the highest BY. There was no significant difference in the WUEb of all three varieties. Although there was no interaction between water regimes, seeding rates and varieties, a moderate irrigation regime and high or low seeding rate are recommended to achieve high WUE.

The distribution of soil organic matter (SOM), nitrogen (N), potassium (K), total calcium carbonate (CaCO3) and pH was studied in relation to three soil tillage practices: conventional (CT) using mouldboad plough followed by three crossing of off-set disc harrow, tooth harrow and seed drill, Reduced (RT) using a chisel, and no-till (NT) using direct driller and 2 plant species: Vicia faba and Durum wheat, grown in a clayey soil of the semi-arid region of Kef (North western Tunisia) during three years 2009-2011. Results showed that, under NT, Vicia faba increased SOM and N in the first fifteen centimeters by 20% and 84% respectively as compared to the CT, and reduced soil pH by 0.1 unit. Indeed, Vicia faba benefited from the residues of the Durum wheat. In contrast, CT buried the residues of the previous crop increasing the rate of SOM and N in the subsoil (30-45 cm depth). This made clear that NT, had the benefit of improving top-soil fertility and putting soil nutrients at the reach of the Vicia faba plant roots. Moreover, NT increased the concentration of K in the top-soil which helped seedlings and young plants resisting biotic and non biotic stresses imposed by the semi-arid environment.

Background: Water and nitrogen (N) are the important compounds in plant production and its deficit is a growth limiting factor. Materials and Methods: A field trial was conducted to evaluate the effect of three nitrogen fertilization applied at different rates (0, 100 and 200 kg N/ha) of three wheat (Triticum turgidum var. durum) cultivars (Maali, Selim and Nasr) under the same cropping practices (sowing date, seeding rate, row space and seeding depth). Durum wheat response was assessed under supplemental irrigation and rainfed conditions. Plant number/m2 (PN), tillers number/plant (NT), spike number/m2 (SN), kernel number/spike (KN), thousand kernel weight (TKW), fresh weight shoot (FWS), dry weight shoot (DWS) and height plant (HP) were studied. Results: Variance analysis showed that all traits were significantly (P<0.01) influence by N fertilization expect NT in general for most cultivars. A signifiant increase in nitrogen application rate had resulted in an increase of component of yield. The optimum yield was produced for all cultivars at 200 kg N/ha rate. Results showed that cultivar Maali and Selim were more affected by nitrogen fertilization than cultivar Nasr. Selim variety showed the important TKW, KN and SP for all N regimes. Regardless of cultivar, results showed that supplemental irrigation significantly increased PN, SN, FWS and TKW with respect to the rained treatment. Maali and Selim were less affected by supplemental irrigation than Nasr. Conclusion: Combined the two factor (Nitrogen and water supply), the optimum yield was produced for all cultivars at supplemental irrigation and nitrogen rate of 200 kg N/ha and the Selim variety had the most performing one. Thus, this variety could be recommended for semi-arid region as Siliana site. Key Word: durum wheat, nitrogen fertilization, semi-arid environment, supplementary irrigation Abbreviations: N: nitrogen; PN: Plant number/m2; TN: tillers number/plant; SN: spike number/m2: KN: kernel number/spike; TKW: thousand kernel weight; FWS: fresh weight shoot; DWS: dry weight shoot and PH: plant height. -------------------------------------------------------------------------------------------------------------------------------------Date of Submission: 25-11-2020 Date of Acceptance: 09-12-2020 -------------------------------------------------------------------------------------------------------------------------------------

Five Tunisian varieties of Kabuli chickpea were characterized based on agro morphological, molecular and biochemical parameters to investigate their genetic variability and yield potential. Randomized complete block design field trials were carried out in the upper semi-arid region of Kef in Tunisia during the 2013-2014 seasons. Data analysis showed significant differences between genotypes for several parameters. The results indicated that these genotypes could be set into two different groups. The first group composed of Bochra and Chetoui genotypes. Kasseb, Neyer and Beja1 were in the second group. Genotypes in each group were closely related to each other according to their common morphological characters such as pod number, one hundred seeds weight and yield. Chetoui and Kasseb varieties are later in comparison to other varieties. Genetic diversity was studied using simple sequence repeat (SSR) markers. Four loci (TA64, TA71, TA96, TA194) were multiallelic. Whereas while two loci (TA72, GAA47) were monomorphic. Polymorphism analysis showed a phylogeny related to genotypes differentiation according to their relatives, origin and several morphological characters. Bochra variety had high amino acids content followed by Chetoui variety. All the varieties were deficient in sulfur amino acids. Chickpeas protein contents were variable and high ranging from 18% to 25%.

Wheat is a staple crop in Tunisia, but little is known about the response of Tunisian durum wheat (Triticum turgidum ssp. durum) and bread wheat (Triticum aestivum L.) to water stress. In semi-arid regions, where cereals are concentrated, grain yield is subject to water deficit especially due to variability in rainfall. Therefore, the objective of this study was to evaluate the response to water stress of three durum wheat (Maali, Nasr and Salim) and two bread wheat (Tahent and Utique) varieties. The experimental design was a complete randomized block, water treatments were rainfed conditions (TO) and irrigation applied at the tillering and flowering stages (T1, control) with three replications per treatment, and data was analyzed by ANOVA and Tukey test to compare treatments means (p <= 0.05). Variables analyzed were grain yield and yield-related components: plants per square meter (NP), tillers per square meter (NT), ears per square meter (NE), seed per ear (NSE) and 1000-kernel weight (TKW). NP, NE, NSE and TKW were significantly affected by water stress, but there was no change on NT. Seed yield was weakly correlated with NE (r=0.376) but significantly correlated with NSE (r=0.604) and NP (r=0.639). Supplemental irrigation increased grain yield by 74.4 %, 42.3 %, 36.1 %, 33.7 % and 24.5 % for Utique, Tahent, Nasr, Maali and Salim, respectively, compared to control. Four drought tolerance indices, stress tolerance index (STI), stress tolerance (TOL), stress susceptibility index (SSI), and mean productivity (MP), were assessed and were adjusted based on grain yield under drought (Y-e) and normal (Y-p) conditions. A positive and significant correlation between Y-s, and Y-p with SSI and PM, respectively, indicate that they are the most suitable variables to select wheat genotypes in drought stress. These indices were able to screen a drought-tolerant genotype (Nasr), which showed the highest STI (1.10). In contrast, Salim showed the lowest STI (0.47) and was considered to be a drought-susceptible genotype.

The impacts of ten previous crop rotations (cereals, legumes and fallow) on Fusarium foot and root rot of durum wheat were investigated for three cropping seasons in a trial established in 2004 in Northwest Tunisia. Fungi isolated from the roots and stem bases were identified using morphological and molecular methods, and were primarily Fusarium culmorum and F. pseudograminearum . Under low rainfall conditions, the previous crop affected F. pseudograminearum incidence on durum wheat roots but not F. culmorum . Compared to continuous cropping of durum wheat, barley as a previous crop increased disease incidence more than fivefold, while legumes and fallow tended to reduce incidence. Barley as a previous crop increased wheat disease severity by 47%, compared to other rotations. Grain yield was negatively correlated with the incidence of F. culmorum infection, both in roots and stem bases, and fitted an exponential model (R 2 = -0.61 for roots and -0.77 for stem bases, P <0.0001). Fusarium pseudograminearum was also negatively correlated with yield and fitted an exponential model (R 2 = -0.53 on roots and -0.71 on stem bases, P < 0.0001) but was not correlated with severity.

The effects of water stress on Fusarium foot and root rot in durum wheat were investigated in growth chamber, greenhouse and field tests in Tunisia. In the seedling stage, emergence of six durum wheat cultivars in the growth chamber was significantly reduced by inoculation with Fusarium culmorum and water stress (P < 0.0001), with more disease under drier conditions. Additionally, the tiller number per mature plant, the 1000 grain weight and disease severity in mature stage were reduced by inoculation in greenhouse studies. In a field test, inoculation with E culmorum significantly reduced the yield (P < 0.001), by more than 17% for Om Rabiaa and 38% for Karim, the two cultivars tested. Yield was also significantly affected by precipitation and irrigation levels. The severity of the disease, estimated by the percentage of white heads, was separately affected by the cultivar (P < 0.001) and inoculation (P = 0.0004). Percentage of white heads was 1.5 and 2 x higher in inoculated plants than non-inoculated for Om Rabiaa and Karim cultivars, respectively. Disease severity was highest in treatments with the greatest water stress. This is the first detailed study of water stress and E culmorum on durum wheat in Tunisia, and indicates that cultivar resistance and irrigation management may be important in the management of Fusarium foot rot. Published by Elsevier Ltd.