CHARACTERIZATION OF SOME ALGERIANS AND FOREIGN LENTIL ACCESSIONS BY QUALITATIVE TRAITS

In the present study an attempt has been made to characterize lentil accessions based on qualitative traits. There were variations among 44 lentil accessions. Erect growth habit was observed in 24 % of the accessions where 8% were from Algeria. Conversely, prostrate growth habit was observed in 34% of the accessions. The majority of the remaining accessions (41.32%) were intermediate. Stem with anthocyanin pigmentation was showed in 44% of the accessions, whereas, 56% had no pigmentation (green stem). About half of the accessions had grey green leaves (53%) and 23% of accessions were light green. Among the characters, flower color showed the highest variation. White flowers were observed in 64% accessions and violet flowers were found in 36% accessions. Flowers, with violet stripes in the standard petal (SVE) were observed in 44% accessions and the majority (56%) lacked violet stripes. Yellow cotyledons were observed in 61% accessions, while the rest (39%) had red cotyledons. The majority of accessions (81%) were observed with brown testa while 14% were green and 5% had yellow testa. Absence of seed coat pattern was observed in 69% accessions. However, 8% accessions with spots, 5% with dots, 16% were marbled and the remaining 2% were complex. Flattened seed shape was observed in 60% of accessions. Conversely, globose shape was observed in 40% of the accessions, among of them 27% were from Algeria

Alfalfa genomic selection for different stress-prone growing regions

Alfalfa (Medicago sativa L.) selection for stress-prone regions has high priority for sustainable crop–livestock systems. This study assessed the genomic selection (GS) ability to predict alfalfa breeding values for drought-prone agricultural sites of Algeria, Morocco, and Argentina; managed-stress (MS) environments of Italy featuring moderate or intense drought; and one Tunisian site irrigated with moderately saline water. Additional aims were to investigate genotype × environment interaction (GEI) patterns and the effect on GS predictions of three single-nucleotide polymorphism (SNP) calling procedures, 12 statistical models that exclude or incorporate GEI, and allele dosage information. Our study included 127 genotypes from a Mediterranean reference population originated from three geographically contrasting populations, genotyped via genotyping-by-sequencing and phenotyped based on multi-year biomass dry matter yield of their dense-planted half-sib progenies. The GEI was very large, as shown by 27-fold greater additive genetic variance × environment interaction relative to the additive genetic variance and low genetic correlation for progeny yield responses across environments. The predictive ability of GS (using at least 37,969 SNP markers) exceeded 0.20 for moderate MS (representing Italian stress-prone sites) and the sites of Algeria and Argentina while being quite low for the Tunisian site and intense MS. Predictions of GS were complicated by rapid linkage disequilibrium decay. The weighted GBLUP model, GEI incorporation into GS models, and SNP calling based on a mock reference genome exhibited a predictive ability advantage for some environments. Our results support the specific breeding for each target region and suggest a positive role for GS in most regions when considering the challenges associated with phenotypic selection.EEA Santiago del EsteroFil: Annicchiarico, Paolo. Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria. Centro di Ricerca Zootecnia e Acquacoltura; ItaliaFil: Nazzicari, Nelson. Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria. Centro di Ricerca Zootecnia e Acquacoltura; ItaliaFil: Bouizgaren, Abdelaziz. Institut National de la Recherche Agronomique du Maroc. Centres Régionaux de Marrakech et de Rabat; MarruecosFil: Hayek, Taoufik. Institut des Régions Arides de Médenine; TunezFil: Laouar, Meriem. Ecole Nationale Supérieure Agronomique. Dép. de Productions Végétales. Laboratoire d’Amélioration Intégrative des Productions Végétales; ArgeliaFil: Cornacchione, Monica. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santiago del Estero; ArgentinaFil: Basigalup, Daniel Horacio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Manfredi. Grupo de Mejoramiento Genético de Alfalfa; ArgentinaFil: Monterrubio Martin, Cristina. Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria. Centro di Ricerca Zootecnia e Acquacoltura; ItaliaFil: Brummer, E. Charles. University of California at Davies. Depeparment of Plant Sciences. Plant Breeding Center,; Estados UnidosFil: Pecetti, Luciano. Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria. Centro di Ricerca Zootecnia e Acquacoltura; Itali

Genetic Variability Induced by Gamma Rays and Preliminary Results of Low-Cost TILLING on M2 Generation of Chickpea (Cicer arietinum L.)

In order to increase genetic variability for chickpea improvement, the Kabuli genotype, variety Ghab4, was treated with 280 Grays of gamma rays (Cobalt 60). Field characterization began with the M2 generation. A total of 135 M2 families were sown in the field resulting in approximately 4,000 plants. Traits related to phenology (days to flowering, days to maturity), plant morphology of vegetative parts (plant height, height of first pod, number of primary branches per plant) and yield (number of seeds per pod, total number of pods per plant, total number of seeds per plant, seed yield and hundred seed weight) were recorded and analyzed to evaluate genetic variability. An evaluation of the efficacy of low-cost TILLING (Targeting Induced Local Lesions IN Genomes) to discover mutations in the M2 generation was undertaken. Mutation screening focused on genes involved in resistance to two important diseases of chickpea; Ascochyta blight (AB) and Fusarium wilt (FW), as well as genes responsible for early flowering. Analysis of variance showed a highly significant difference among mutant families for all studied traits. The higher estimates of genetic parameters (genotypic and phenotypic coefficient of variation, broad sense heritability and genetic advance) were recorded for number of seeds per plant and yield. Total yield was highly significant and positively correlated with number of pods and seeds per plant. Path analysis revealed that the total number of seeds per plant had the highest positive direct effect followed by hundred seed weight parameter. One cluster from nine exhibited the highest mean values for total number of pods and seeds per plant as well as yield per plant. According to Dunnett’s test, 37 M2 families superior to the control were determined for five agronomical traits. Pilot experiments with low-cost TILLING show that the seed stock used for mutagenesis is homogeneous and that small mutations do not predominate at the dosage used

Variability in Responses to Phoma medicaginis Infection in a Tunisian Collection of Three Annual Medicago Species

Spring black stem and leaf spot, caused by Phoma medicaginis, is an issue in annual Medicago species. Therefore, in this study, we analyzed the response to P. medicaginis infection in a collection of 46 lines of three annual Medicago species (M. truncatula, M. ciliaris, and M. polymorpha) showing different geographic distribution in Tunisia. The reaction in the host to the disease is explained by the effects based on plant species, lines nested within species, treatment, the interaction of species × treatment, and the interaction of lines nested within species × treatment. Medicago ciliaris was the least affected for aerial growth under infection. Furthermore, the largest variation within species was found for M. truncatula under both conditions. Principal component analysis and hierarchical classification showed that M. ciliaris lines formed a separate group under control treatment and P. medicaginis infection and they are the most vigorous in growth. These results indicate that M. ciliaris is the least susceptible in response to P. medicaginis infection among the three Medicago species investigated here, which can be used as a good candidate in crop rotation to reduce disease pressure in the field and as a source of P. medicaginis resistance for the improvement of forage legumes

Les pipes doléritiques CAMP du bassin de Tindouf : état des lieux et perspectives métallogéniques et pétrolières

International audienceLe bassin de Tindouf en Algérie a connu une intense activité magmatique datée de la limite Trias/Jurassique et appartenant à la grande province magmatique de l’Atlantique central (CAMP). Ce magmatisme s’est manifesté dans la région par la mise en place d’immense sills doléritiques au sein de la couverture paléozoïque du bassin et de longs dykes qui recoupent l’ensemble de cette couverture. Un troisième mode de gisement lié à cette activité magmatique a été signalé depuis longtemps, mais n’a jamais fait l’objet d’études détaillées : il s’agit de cheminées doléritiques ou petits massifs circulaires qui ressemblent à des pipes. Elles sont visibles au cœur des anticlinaux et dômes de la région et recoupent les couches sédimentaires à l’emporte-pièce en digérant partiellement son encaissant. Dans cette communication, nous présentons une synthèse des derniers travaux que nous avons réalisés sur les pipes doléritiques de la CAMP du bassin de Tindouf et les perspectives qui en résultent, notamment d’un point de vue métallogénique et pétrolier. Les études pétrologique et géochimique réalisées sur les dolérites des pipes du bassin de Tindouf ont mis en évidence des particularités qui les distinguent des autres dolérites de la CAMP décrites dans la littérature. Les dolérites des pipes montrent une texture granophyrique riche en quartz, feldspath alcalin et biotites, contrairement aux autres dolérites de la CAMP qui présentent des cortèges minéralogiques beaucoup plus mafiques et anhydres. Par ailleurs, elles se caractérisent par une abondance de sulfures disséminés et de xénolithes de carbonates. D’un point de vue géochimique, les dolérites des pipes montrent une composition évoluée et leurs spectres des terres rares et multiéléments présentent le plus fort enrichissement en REE at autres LILE comparés aux autres dolérites de la CAMP, de fortes anomalies négatives en Ti et Sr, et une forte anomalie positive en Pb. Les diagrammes et modélisations géochimiques indiquent clairement que les magmas des dolérites de pipes représentent les produits évolués de la dernière venue magmatique de la CAMP dans la région (unité récurrente) avec une importante assimilation de l’encaissant. Nous avons daté par la méthode 40Ar/39Ar une biotite d’un échantillon de pipe qui a fourni un âge (193,7 ± 3,4 Ma) beaucoup plus jeune que le pic du magmatisme de la CAMP (autour de 201 Ma), confirmant la mise en place tardive de ces pipes comme suggérée par la géochimie. Des datations supplémentaires sur les pipes du bassin de Tindouf sont en cours pour affiner l’âge de mise en place de ces structures magmatiques dans le bassin Tindouf. D’un point de vue métallogénique, la mise en place des magmas sous forme de pipes avec une assimilation importante des roches encaissantes, notamment des argiles riches en matière organique du Dévonien supérieur, l’abondance des sulfures disséminés dans les dolérites des pipes indiquant une saturation du magma parent en sulfures, et la présence de corps minéralisés autour des pipes, sont autant d’ingrédients favorables à la concentration de minéralisations riches en platine et autres PGE. Des analyses des teneurs en Pt/Pd d’une vingtaine d’échantillons de dolérites de pipes riches en sulfures et de corps minéralisés associés sont en cours pour évaluer les potentialités en PGE de ces structures magmatiques. D’un point de vue pétrolier, nous avons pu clairement identifier les pipes doléritiques sur les sections sismiques du flanc nord du bassin de Tindouf. La signature de ces pipes a été mal interprétée dans les rapports des pétroliers, qui le sont attribués tantôt à des zones bréchiques ou à des failles, tantôt à des défauts dans les sections sismiques. Une interprétation correcte des signatures de pipes sur les sections sismiques réalisées dans le Sahara algérien est désormais possible. Par ailleurs, l’utilisation des sections sismiques pour l’identification de structures de pipes offre d’immenses perspectives dans le domaine métallogénique, et plus précisément dans l’exploration du diamant, étant donné la prédominance de ce mode de gisement dans la mise en place des venues kimberlitiques. Nous montrerons un exemple d’une section sismique réalisée dans le bassin de Reggane montrant clairement une importante structure de pipe quipourrait représenter une venue kimberlitique, en relation avec la concentration alluvionnaire diamantifière du Djebel Aberraz, située à proximité. Un deuxième intérêt de l’étude de ces pipes doléritiques du bassin de Tindouf en relation direct avec le système pétrolier de ce bassin est la mise en évidence de la formation de plis (ou dômes) forcés au-dessus des pipes. La mise en place de magmas de pipes à faible profondeur engendre une déformation des couches sédimentaires sus-jacentes à l’origine de la formation de plusieurs dômes (à l’exemple de celui d’Assejmi formé au-dessus du pipe d’Assejmi découvert par notre équipe) et plis (à l’exemple de la structure plissée de Draa el Kelba formée aux dépens du grand pipe localisé au cœur de cette structure). Ceci explique la présence systématique des pipes doléritiques au cœur des structures anticlinales de la région. Or, la plupart des sondages pétroliers réalisés dans le flanc nord du bassin de Tindouf ont été forés au cœur de ces dômes et structures (le dernier forage d’exploration de la SONATRACH, OMLAE-01, a été réalisé à proximité du grand pipe de Draa El Kelba). Le fait que ces structures tectoniques (assimilées à des pièges pétroliers), considérées jusqu’à maintenant comme des structures hercyniennes, sont en réalité des plis et dômes forcés formés au-dessus de pipes doléritiques au début du Jurassique modifie complétement les éléments du système pétrolier du flanc nord du bassin de Tindouf, et explique en partie les résultats négatifs de ces sondages pétroliers. Ces nouvelles données permettront de réorienter l’exploration pétrolière dans la région vers d’autres types de pièges pétroliers (en évitant ces plis et dômes forcés) avec certainement un gain financier important. Enfin, la mise en place à l’aube de la période Jurassique de ces pipes doléritiques riches en sulfures et carbonates, et les émanations en gaz carbonique et sulfureux associées, pourrait avoir une influence sur l’environnement durant cette période

Development and Proof-of-Concept Application of Genome-Enabled Selection for Pea Grain Yield under Severe Terminal Drought

Terminal drought is the main stress limiting pea (Pisum sativum L.) grain yield in Mediterranean environments. This study aimed to investigate genotype × environment (GE) interaction patterns, define a genomic selection (GS) model for yield under severe drought based on single nucleotide polymorphism (SNP) markers from genotyping-by-sequencing, and compare GS with phenotypic selection (PS) and marker-assisted selection (MAS). Some 288 lines belonging to three connected RIL populations were evaluated in a managed-stress (MS) environment of Northern Italy, Marchouch (Morocco), and Alger (Algeria). Intra-environment, cross-environment, and cross-population predictive ability were assessed by Ridge Regression best linear unbiased prediction (rrBLUP) and Bayesian Lasso models. GE interaction was particularly large across moderate-stress and severe-stress environments. In proof-of-concept experiments performed in a MS environment, GS models constructed from MS environment and Marchouch data applied to independent material separated top-performing lines from mid- and bottom-performing ones, and produced actual yield gains similar to PS. The latter result would imply somewhat greater GS efficiency when considering same selection costs, in partial agreement with predicted efficiency results. GS, which exploited drought escape and intrinsic drought tolerance, exhibited 18% greater selection efficiency than MAS (albeit with non-significant difference between selections) and moderate to high cross-population predictive ability. GS can be cost-efficient to raise yields under severe drought

Adaptation patterns of sixteen alfalfa (Medicago sativa L.) cultivars across contrasting environments of Algeria and implications for the crop improvement

The additive main effects and multiplicative interaction analysis was applied to assess the genotype × environment interaction (GEI) effects and stability for 4-year dry matter yield (DMY) of 16 alfalfa (Medicago sativa L.) cultivars of diversified geographic origin grown in four Algerian environments given by the combination of two water managements (rainfed and irrigated) and two evaluation sites, viz. the sub-humid location of Alger and the semi-arid, salinity-affected site of Hmadna. The analysis of variance (ANOVA) revealed significant variation among cultivars and environments (P<0.001). The GEI was significant (P<0.001) and the environment main effect had greater influence than the genotype effect on long-term yield according to ANOVA. Rainfed conditions had 41.6% and 48.5% lower yield than the irrigated ones in Alger and Hmadna, respectively. Alfalfa cropping in the semiarid location caused lower DMY than in the sub-humid one (– 38.0% under irrigated and –45.2% under rainfed conditions) and a slightly lower persistence over the 4-year period. Outstanding environment-specific cultivar responses were observed, fully justifying the large GEI effects, although the Italian cultivar Sicilian ecotype had remarkable yield stability and good mean yield. The American variety Ameristand 801S and the Moroccan landrace Erfoud 1 were the most salt-tolerant cultivars. The evaluated germplasm, and particularly some exotic cultivars, could be used as parents to breed new varieties more adapted to drought and salinity in the Mediterranean basin

Genetic Diversity and Differentiation of Eleven Medicago Species from Campania Region Revealed by Nuclear and Chloroplast Microsatellites Markers

The species belonging to the genus Medicago are considered a very important genetic resource at global level both for planet’s food security and for sustainable rangelands management. The checklist of the Italian flora (2021) includes a total number of 40 Medicago species for Italy, and 27 for Campania region, with a number of doubtful records or related to species no more found in the wild. In this study, 10 Medicago species native to Campania region, and one archaeophyte (M. sativa), identified by means of morphological diagnostic characters, were analyzed in a blind test to assay the efficacy of nine microsatellite markers (five cp-SSRs and four n-SSRs). A total number of 33 individuals from 6 locations were sampled and genotyped. All markers were polymorphic, 40 alleles were obtained with n-SSRs ranging from 8–12 alleles per locus with an average of 10 alleles per marker, PIC values ranged from 0.672 to 0.847, and the most polymorphic SSR was MTIC 564. The cp-SSRs markers were highly polymorphic too; PIC values ranged from 0.644 to 0.891 with an average of 0.776, the most polymorphic cp-SSR was CCMP10. 56 alleles were obtained with cp-SSRs ranging from 7 to 17 alleles per locus with an average of 11. AMOVA analysis with n-SSR markers highlighted a great level of genetic differentiation among the 11 species, with a statistically significant fixation index (F(ST)). UPGMA clustering and Bayesian-based population structure analysis assigned these 11 species to two main clusters, but the distribution of species within clusters was not the same for the two analyses. In conclusion, our results demonstrated that the combination of the used SSRs well distinguished the 11 Medicago species. Moreover, our results demonstrated that the use of a limited number of SSRs might be considered for further genetic studies on other Medicago species