Criblage De Quelques Genotypes De Ble Dur (Triticum Durum Desf.) Sous Un Stress Salin En Culture De Pot

In this study, five durum wheat (Triticum turgidum ssp durum) genotypes: Agili, Arbi, Derbassi, Karim and Maali were assessed for 04 agronomical parameters associated with salinity-tolerance. Genotypes were grown under glasshouse conditions and exposed to five salinity levels (control, 3g/l, 6 g/l, 9 g/l et 12 g/l of NaCl) to evaluate their tolerance using their biomass and the relative salt-susceptibility index: R.S.S.I = R.B.D./S.I.I. (R.B.D.: relative biomass deficit and S.I.I.: salinity intensity index).Genotypic screening was also based on agro-morphological traits: tillers number/plant, plant height, grains number/spike and 1000 kernel weight. Analysis of variance revealed a significant (p<0.001) difference between treatments and genotypes. This difference indicated a large variability between genotypes. Results showed also that Maali variety had the higher agronomic performance and the lower R.S.S.I than other genotypes

Assessment Of Adaptability And Stability Of Six Tunisian Cereal Genotypes Under Rainfed Conditions And At Two Semi Arid Environments

Three durum wheat (Nasr, Maâli and Salim), two bread wheat (Tahent and Utique) and two barley varieties (Manel and Kounouz) were assessed in two different semi arid locations under rainfed conditions in 2012-2013 growing season for yield related traits performances, stability and adaptability parameters. For determining adaptability and stability of genotypes, regression coefficient (bi) and variance of deviation from regression (S²di) are used. The evaluation was based on five agro-morphological traits: tiller number/plant, spike number/m2, plant number/m2, 1000 kernel weight and grain number/ spike. Variance analysis indicated a highly significant (p<0.05) effect of locations and genotypes for all studied traits. Also, the interaction between the genotypes and environments found to be highly significant (p<0.001) for all studied traits except the tiller number/plant. Analysis of stability showed that there were differences in stability performances among the genotypes for the traits tested. The unstability for spike number/m², plant number/m 2, 1000kernel weight and grain number/spike among the genotypes was originated from the high mean squares of deviation from regression. Analysis of AMMI model showed that Principal Components (PC) Analysis indicated that the two PCs explained 78.17% (PC1 = 41.51% and PC2 = 36.66%) of the total variation. Results showed that the group of genotypes Nasr, Tahent, Kounouz and Manel having wide adaptability and could be recommended for cultivation across diverse environments

Yield of Durum Wheat Cultivar Grown under Different Nitrogen Regimes and Rainfed Conditions

The experiment was conducted in randomized complete block design with three replications in two different locations (Kef and Bousselem). The effect of four nitrogen treatments (0, 75, 100, 120 and 140 kg/ha of N) was assessed for Maali durum wheat variety on five agronomic traits: biological yield, grain yield, harvest index, 1000 kernel weight and nitrogen use efficiency. Analysis of variance revealed significant effect (P< 0.01; P< 0.001) of the nitrogen treatments for all studied traits. However, no nitrogen treatment x site interaction was noted. Except for nitrogen use efficiency, both location exhibited significant variation (p<0.01) for all the traits examined. Biological yield, grain yield, harvest index, 1000 kernel weight and nitrogen use efficiency increased with an increase in nitrogen levels. In comparison to kef site, greatest results were obtained in Bousselem site under all nitrogen levels for all measured traits. Maximum average yield (2157.27 kg/ha) and (3013.11 kg /ha) was unregistered under N4 treatment (140 kg/ha) in Kef and Boussalem site respectively. A significant and positive correlation was noted between nitrogen rates and biological yield (r = 0.74**), grain yield (r = 0.66**), harvest index (r = 0.84**) and 1000 kernel weight (r = 0.85**). In this region, it seems that the application of 140 kg/ha of N fertilization lead to great agronomic performance of Maali durum wheat variety

Multi-Environment Screening of Durum Wheat Genotypes for Drought Tolerance in Changing Climatic Events

Durum wheat is the most widely grown cereal in Tunisia, but its production is threatened by drought, which is exacerbated by climate change. This study aimed to identify drought-tolerant durum wheat genotypes from five modern varieties and six landraces in a multi-environment trial at two sites (Kef and Siliana, Tunisia) during three growing seasons under rainfed and irrigated conditions. Six drought tolerance indices (mean productivity (MP), geometric mean productivity (GMP), stress susceptibility index (SSI), tolerance index (TOL), stress tolerance index (STI), and yield stability index (YSI)) were used to evaluate the 11 genotypes. The environment was the dominant source of variation for grain yield (GY; 94.27%), followed by the environment × genotype interaction (4.06%) and genotype (1.65%). Cluster analysis based on GY identified four environment-based groups with distinct water treatments, extreme minimum/maximum temperatures, and rainfall. Principal component analysis and a correlation matrix revealed that drought tolerance indices significantly correlated with GY in non-stressed and stressed conditions and could be separated into four groups. Based on STI, MP, and GMP, G6 and G8 (landraces) were the most drought-tolerant genotypes attaining high GY in both conditions. TOL was able to discriminate G1, G3, and G5 (modern varieties) as well as drought-susceptible genotypes, all of which were suitable for irrigation. Genotypes G7, G9, G10, and G11 (landraces), which had high SSI and lowest STI, MP, GMP, and YSI values, were susceptible to drought and were thus not suitable for cultivation in both conditions. Finally, G2 and G4 (modern varieties), which had an intermediate rank for different indices, were classified as semi-tolerant or sensitive genotypes. Drought tolerance indices and genotype ranks were helpful tools to screen drought-tolerant genotypes with a large adaptation to a range of environments, namely irrigated and rainfed conditions (landraces G6 and G8), or genotypes with the ability to adapt (modern varieties G1, G3, and G5) to irrigated conditions

Distribution and pheotypic variability aspects of some quantitative traits among durum wheat accessions

A durum wheat ( Triticum durum Desf.) collection with 111 accessions represents a large part of the collection of Triticeae species in Tunisia were evaluated for six qualitative traits: seed colour, seed size, glume colour, glume pubescence, spike density and beak length. Distribution of traits showed that this germoplasm was dominated by dense spike, white and glabre glume, long beak, brown and large grain. Phenotypic diversity is determined by the index Shannon-Weaver (H'). This index calculated for each parameter revealed that spike density (H' =0.86), glume pubescence (H' =0.80) and glume colour (H' =0.79) showed the best diversity index. Seed size showed the weakest index (H' =0.69) which indicated a low phenotypic variability for this parameter. This durum wheat germoplasm presented an average of diversity index about 0.77, showing a large diversity of this collection. These values showed that the germoplasm has a relatively important diversity, confirming that Tunisia is one of the principal durum wheat secondary centres of diversification. This genetic diversity can be exploited in improvement programmes.Une collection de blé ( Triticum durum Desf.) avec 111 nouvelles acquisitions représentant une grande partie de la collection des espèces Triticeae en Tunisie avaient été évalués pour six traits qualitatifs: couleur de semences, taille de semences, la couleur de glume, pubescence du glume, densité du pointe et longueur de bec. La distribution des traits avait montré que cette germoplasm avait été dominée par une dense pointe, glume blanc et glabre, long bec, grain brun et grande. La diversité phénotypique est déterminée par l'index de Shannon-Weaver (H'). Cet index calculé pour chaque paramètre a révélé que la densité du pointe (H' = 0,86), la pubescence du glume (H' = 0,80) et la couleur du glume (H' = 0,79) avait montré le meilleur indice de diversité. La taille de semences avait montré le plus faible index (H ' = 0,69), ce qui avait indiqué une variabilité phénotypique faible pour ce paramètre. Cette germoplasm de blé dur a présenté une moyenne de l'index de diversité d'environ 0,77; montrant une grande diversité de cette collection. Ces valeurs ont montré que cette germoplasm a une diversité relativement importante, ce qui a confirmé que la Tunisie est l'un de principaux centres secondaire de diversification de blé dur. Cette diversité génétique peut être exploitée dans les programmes d'amélioration

Adoption of Durum Wheat Cultivar ‘Salim’ with a Technical Package and Its Resilience to Climate Change Impacts in Smallholders: Case of Nebeur/Kef Region, Tunisia

In recent years, there has been an urgent need for local strategies to ensure food sustainability in Tunisia, recognized as a climate change hotspot region. In this context, adaptation measures, including the adoption of high-yielding durum wheat cultivars with adequate agronomical practices, are an important avenue to improving the productivity of the smallholders that represent 80% of Tunisian farmers. Thus, this study highlights the impact of (i) the adoption of the recently marketed durum wheat cultivar ‘Salim’ as compared to the common cultivar ‘Karim’ and the transfer of a technical package to 11 farmers in the Nebeur delegation/Kef-Tunisia (semi-arid region) during the 2013/2014 and 2014/2015 cropping seasons, and (ii) climate change on the expected mean grain yield and biomass by 2070, using the CropSyst agronomic cultivation model based on multi-year crop simulations run with a daily weather series (2020–2070). The adoption of ‘Salim’ with the recommended package, compared to ‘Karim’ with the farmer practices, significantly increased the grain yield (37.84%) and biomass (55.43%). Otherwise, the impact of the 0.8 °C temperature rise on the potential yields and biomass over the next 51 years was positive. Contrary to expectations, the yield increases for the two cultivars were very close, but the yield of ‘Salim’ (36.02 q ha−1) remains much higher than that of ‘Karim’ (23.34 q ha−1). On other hand, ‘Salim’ experienced a higher increase for biomass compared to that of ‘Karim’. These results indicate that the adoption of the ‘Salim’ cultivar with its technical package might be considered as a strategy of adaptation to Nebeur conditions and to future climate change events

Screening of Durum Wheat Cultivars for Selenium Response under Contrasting Environments, Based on Grain Yield and Quality Attributes

In the literature, little information is available on the effect of Selenium (Se) on durum wheat yield and grain quality performances. A field investigation was conducted to explore the effect of exogenous Se foliar supply on two types of durum wheat germplasm; i.e., 16 advanced lines and nine modern varieties. The Se effect was assessed on grain yield as well as on technological quality traits (moisture, protein and gluten contents, Zeleny sedimentation index, and deformation energy) in two contrasting environments in Tunisia, namely Kef–Boulifa (semi-arid region) and Beja (sub-humid region). The results displayed significant effects of environments, Se foliar application, and cultivars on grain yield and quality attributes. For grain yield performance, the beneficial effect of Se was more pronounced under the Kef–Boulifa environment, and conversely for the grain quality. A genetic variation was observed within and among the two environments under both Se treatments (with and without Se). Notably, the Se-treated advanced lines displayed the highest grain yield under Kef–Boulifa and Beja conditions. Although these cultivars showed better grain quality in both sites, the modern varieties valorized the Se foliar application better. Cultivars that recorded the highest values for the studies attributes were not necessarily those that valorized the Se supply better. Interestingly, some advanced lines have noted superiority compared to the modern varieties. In this study, cultivars that combine both good yield and good grain quality were determined for semi-arid (L11, L1, Dhahbi, and Maali) and sub-humid (L2, L14, L6, L3, Salim, and INRAT 100) zones. The screening results provide genetic material that could be exploited in breeding programs to improve Se use efficiency

Phenotypic diversity of Tunisian durum wheat landraces

Tunisia is considered as a diversification centre of durum wheat ( Triticum durum Desf.) and barely ( Hordeum vulgare ). It is characterised by large genetic diversity; however, several genotypes are in the process of disappearance. The safeguard and rehabilitatation of this genetic inheritance requires genetic characterisation, evaluation and in-situ and ex-situ conservation. In this context, a local collection of thirty durum wheat accessions was evaluated using agronomical traits. Three other phenological traits: days to maturity, days to heading and filling period were evaluated. The phenotypic diversity was determined by the Shannon-Weaver diversity Index (H') revealing that number of kernel/spike (H'=0.91), yield (H'=0.89), plant height (H'=0.87) and thousand kernel weight (H'=0.86) had the highest diversity index. Flag leaf area (H'=0.32) showed the weakest index. This germplasm presented average diversity (0.77) showing a large genetic variability. Correlations between traits showed a significant positive relation between yield and spikeless tillers/plant (0.90), thousand kernel weight (0.39), plant height (0.35) and flag leaf area (0.36), suggesting the usefulness of these parameter for selecting for improving grain yield. The components analysis explained 59.61% of total variability and led to identification of a group of accessions Jeneh kotifa 1, Jeneh kotifa 2, Jeneh kotifa 3, Sbei glabre, Hamira 1, Hamira 2, Biskri glabre, Mahmoudi, Biskri glabre AP2, Swabaa Elgia, Sbei, and Mahmoudi glabre showing the best agronomical characteristics. These genotypes can, therefore, be used as parents for the improvement of durum wheat.La Tunisie est un centre de diversité génétique du blé dur ( Triticum durum Desf.) et de l'orge ( Hordeum vulgare ). En dépit de la large diversité génétique au niveau du germoplasme local, plusieurs génotypes sont en voie de disparition. La sauvegarde et la réhabilitation de ce patrimoine génétique nécessitent sa caractérisation, son évaluation ainsi que sa conservation in situ et ex situ. Dans ce contexte une collection locale de trente genotypes de blé dur a été évaluée utilisant des paramètres agronomiques. Trois autres paramètres phénologiques à savoir jours de maturation, jours de rétablissement et période de remplissage étaient aussi évaluées. La diversité phénotypique determinée par l'index de diversité de Shannon-Weaver (H') a révélé que le nombre de grains par épi (H'=0.91), rendement (H'=0.89), hauteur des plants (H'=0.87) et le poids de 1000 grains (H'=0.86) avaient un index de diversité le plus élevé. La surface foliare (H'=0.32) a montré un index le plus faible. Ce germplasm presentait un index de diversité moyen de 0.77 montrant ainsi une large variabilité génétique. Les corrélations entre les paramètres a montré une relation positive significative entre le rendement et le nombre de talles d'épillets par plant (0.39), le poids de 1000 grains (0.35) et la surface foliaire (0.36), suggérant ainsi l'utilité de ces paramètres de sélection pour l'amélioration du rendement en grains. L'analyse des composants a expliqué 59.61% de la variabilité totale et a conduit à identifier un groupe de genotypes entre autre kotifa 2, Jeneh kotifa 3, Sbei glabre, Hamira 1, Hamira 2, Biskri glabre, Mahmoudi, Biskri glabre AP2, Swabaa Elgia, Sbei, Mahmoudi glabre montrant les meilleures caractéristiques agronomiques. Ces génotypes peuvent donc être utilisés comme parents pour l'amélioration de blé dur

Use of Biostimulants: Towards Sustainable Approach to Enhance Durum Wheat Performances

The use of biostimulant (BS) holds a promising and environmental-friendly innovation to address current needs of sustainable agriculture. The aim of the present study is twofold: (i) assess the potential of durum wheat seed coating with microbial BS (‘Panoramix’, Koppert), a mix of Bacillus spp., Trichoderma spp., and endomycorrhiza, compared to two chemical products (‘Spectro’ and ‘Mycoseeds’) through germination bioassay, pot and field trials under semi-arid conditions, and (ii) identify the most effective method of BS supply (‘seed coating’, ‘foliar spray’, and ‘seed coating + foliar spray’) under field conditions. For this purpose, three modern durum wheat cultivars were tested. ‘Panoramix’ was the most efficient treatment and enhanced all germination (germination rate, and coleoptile and radicle length), physiological (relative water content, chlorophyll content, and leaf area), and agro-morphological (plant height, biomass, seed number per spike, thousand kernel weight, and grain yield) attributes. Unexpectedly, the individual application of ‘Panoramix’ showed better performance than the combined treatment ‘Panoramix + Spectro’. Considering the physiological and agro-morphological traits, the combined method ‘seed coating + foliar spray’ displayed the best results. Principal component analysis confirmed the superiority of ‘Panoramix’ treatment or ‘seed coating + foliar spray’ method. Among tested durum wheat cultivars, ‘Salim’ performed better especially under ‘Panoramix’ treatment, but in some case ‘Karim’ valorized better this BS showing the highest increase rates. Based on these study outcomes, ‘Panoramix’ might be used as promising sustainable approach to stimulate durum wheat performance