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Spot form of net blotch (SFNB), caused by the necrotrophic fungus Pyrenophora teres f. maculata (Ptm), is considered one of the emerging and devastating foliar diseases of barley. Deployment of host resistance against this pathogen remains one of the most effective strategies for its sustainable management. The SFNB resistance in a panel of 336 diverse barley genotypes (AM-2014) was evaluated against three isolates (FGO-Ptm [USA], SM4-2 [Morocco], and SM30-1 [Morocco]), at the seedling stage and under natural conditions in seven environments in Morocco at the adult-plant stage. We identified nine barley genotypes that confer high SFNB resistance in at least five distinct environments and against two isolates. The AM-2014 panel was genotyped with 9K single nucleotide polymorphism (SNP) using an Illumina Infinium select assay. Genome-wide association studies (GWAS) were carried out using mixed linear models accounting for population structure as covariates. Significant marker-trait associations were subject to false discovery rate (FDR) at qQRpts4, QRpt6, QRpt7, and SFNB-3H-58.64, while the remaining may represent novel loci. Together, the associated SNPs and resistance sources identified in this study will be useful resources for SFNB resistance breeding.

International audience; This study was conducted to identify stable resistance to net form of net blotch (NFNB) in spring barley in Moroccan environments. Seedling resistance to NFNB was evaluated by inoculating 336 barley genotypes with two NFNB isolates LDNH04Ptt-19 and TD-10 in the greenhouse. These genotypes were evaluated for adult plant resistance to NFNB under seven environments in Morocco in 2015 and 2016. The disease severity was estimated at GS 77-87 on barley leaves using a double-digit scale. To investigate stability of resistance, 149 barley genotypes were subjected to AMMI analysis. At the seedling stage, differential responses of barley genotypes to different NFNB isolates were identified, whereas genotypes had variable stability to NFNB resistance at the adult stages. Five genotypes, AM-68, AM-95, AM-250, AM-267 and AM-322, were resistant to both NFNB isolates at the seedling stage. There were significant (p < .001) effects of genotype (G) and G x E interaction on NFNB severity for barley genotypes at the adult stage. The principal components, IPCA1 and IPCA2, accounted for 48.4% and 18.7% variation for NFNB severity, respectively. The AMMI stability values (ASVs) ranged from 0.01 to 15.5, and fifty-nine barley genotypes had stable responses (ASV

The aims of this study were to identify resistance to spot form of net blotch (SFNB) in spring barley and to investigate the stability of SFNB resistance in Morocco. The seedling resistance to SFNB was evaluated by inoculating 340 barley genotypes with the Pyrenophora teres F. maculata (Ptm) isolate FGOB10Ptm-1 (FGO) in the greenhouse. The same barely genotypes were evaluated for adult-stage plant resistance to SFNB in field trials in Morocco. All experiments were conducted in alpha-lattices with two replicates. SFNB disease severity was estimated on barley leaves using double digit scale. To investigate the stability of both qualitative and quantitative resistance to SFNB, 104 barley genotypes were subjected to AMMI analysis. Differential responses of SFNB barley resistance to FGO were found at the seedling stage in the greenhouse. Twelve genotypes showing scores of

Plant breeders are interested in using diverse genotypes in hybridization that can segregate for traits of importance with possibility of selection and genetic gain. Information on molecular and agro-morphological diversity helps the breeders reduce the effort for parental selection and helps the advancement of generations. A phenotypic and molecular diversity study, using 24 traits (agronomic and disease) and 6519 SNPs in a diverse collection of 336 spring barley genotypes, was carried out at Marchouch and Jemma Shiam research stations in Morocco. Based on structure and multivariate analyses, strong differentiation between the two- and six-row types were observed. The linkage disequilibrium (LD) decay of the current collection (for the combined population) was up to 3.58 cM (r 2 = 0.15) while LD decay were estimated 3.91 and 2.36 cM for two- and six-row barley, respectively. PCA of agro-morphological traits revealed grain per spike, net form of net blotch (NFNB), spot form of net blotch (SFNB), and 1000 kernel weight were the most discriminatory traits in the current collection. Association mapping in the two independent populations will be ideal for identification of markers, and QTL related to traits. The generated information on relatedness between individuals will help identify diverse genotypes for breeding programs.

Net form of net blotch (NFNB) of barley (Hordeum vulgare L.), caused by Pyrenophora teres f. teres (Ptt) Drechsler (anamorph: Drechslera teres [Sacc.] Shoem.), is considered one of the major constraints of successful barley production in major barley growing regions of the world. Resistance to NFNB was evaluated in a barley collection of 336 genotypes (AM-2014), at seedling stage using isolates LGDPtt.19 and TD10 in the USA, and adult stage in seven hotspot environments in Morocco. The AM-2014 panel was genotyped with 9K SNP markers and genome-wide association studies (GWAS) were carried out using mixed linear model (MLM: Q + K) accounting for population structure (Q) and kinship (K) as covariates. Significant (P

In faba bean, field based winter-hardiness is a complex trait that is significantly correlated to frost tolerance. Frost tolerance could be used to indirectly select for faba bean winter-hardiness. The aim of this study was to identify putative QTL associated with frost tolerance and auxiliary traits and to quantify the efficiency of marker assisted selection. Thus, 101 recombinant inbred lines derived from the cross between two frost tolerant lines were tested for their hardened and unhardened frost tolerance and for their leaf fatty acid content in both treatments. Significant differences among the RIL were observed for all studied traits. For frost tolerance, five putative QTL were detected; three for unhardened frost tolerance that explained 40.7% (8.6% after cross-validation, CV) of its genotypic variance and two for hardened frost tolerance that explained 21.8% (1.0% after CV). For fatty acid content, three QTL were detected for oleic acid content in unhardened leaves that explained 62.9% (40.6% after CV) of its genotypic variance. This fatty acid was significantly correlated with unhardened frost tolerance. The unbiased genotypic variance explained enabled to draw realistic prospects of MAS for frost tolerance. In this study, combined MAS was more efficient than classical phenotypic selection and was expected to be higher on larger populations at early generations. Moreover, favourable alleles inherited from the exotic line BPL 4628 could be introgressed to European winter-hardy beans for further improvement. peerReviewed

Frost tolerance is a main component of winter-hardiness and improving it would promote faba bean (Vicia faba L.) cropping in cool-temperate regions. In many species, leaf fatty acid composition was found to be related to frost tolerance. The objective of this study was to determine, in a representative sample of genotypes, the effect of hardening on leaf and stem (1) frost tolerance and (2) fatty acid composition, and to seek correlations between them. First leaf, second leaf and stem of 31 faba bean genotypes were analyzed after hardening and without hardening. High frost tolerance of known winter genotypes and several experimental lines was shown. Hardening had a significant, positive effect on frost tolerance of all three organs. Stems were on average more frost tolerant than leaves. Hardening induced significant changes in the fatty acid composition: oleic acid decreased significantly in leaves by 3.24% and in stems by 1.77%, whereas linolenic acid increased in leaves by 6.28% and in stems by 9.06%. In stems, correlations between frost tolerance and fatty acid composition were not significant. Correlation coefficients strongly indicated that non-hardened oleic acid content, changes in oleic acid and in linoleic plus linolenic acid content in leaves partly explained their frost tolerance; 0.347 (P

Background: Traditional agrosystems are the places were crop species have evolved and continue to evolve under a combination of human and environmental pressures. A better knowledge of the mechanisms underlying the dynamics of crop diversity in these agrosystems is crucial to sustain food security and farmers’ self-reliance. It requires as a first step, anchoring a description of the available diversity in its geographical, environmental, cultural and socio-economic context. [br/] Methods: We conducted interviews with farmers cultivating durum wheat in two contrasted traditional agrosystems of Morocco in the Pre-Rif (163 farmers) and in the oases of the Atlas Mountains (110 farmers). We documented the varietal diversity of durum wheat, the main characteristics of the farms, the farming and seed management practices applied to durum wheat, and the farmers’ perception of their varieties. [br/] Results: As expected in traditional agrosystems, farmers largely practiced diversified subsistence agriculture on small plots and relied on on-farm seed production or informal seed exchange networks. Heterogeneity nevertheless prevailed on many variables, especially on the modernization of practices in the Pre-Rif region. Fourteen (resp. 11) traditional and 5 (resp. 3) modern varieties were identified in the Pre-Rif region (resp. in the Atlas Mountains). The majority of farmers grew a single variety, and most traditional varieties were distributed in restricted geographical areas. At the farm level, more than half of the varieties were renewed in the last decade in the Pre-Rif, a more rapid renewal than in the Atlas Mountain. Modern varieties were more prevalent in the Pre-Rif region and were integrated in the traditional practices of seed production, selection and exchange. They were clearly distinguished by the farmers from the landraces, the last ones being appreciated for their quality traits. [br/] Conclusions: The surveyed traditional agrosystems constitute open, dynamic and heterogeneous entities. We suggest that competing factors could favour or limit the cultivation of improved varieties and the erosion of original durum wheat diversity. This first description opens the way to focused further investigations, including complementing variety names with cultural, genetic and phenotypic information and unravelling the multidimensional factors and consequences of modern variety adoption.

Background Crop diversity managed by smallholder farmers in traditional agrosystems is the outcome of historical and current processes interacting at various spatial scales, and influenced by factors such as farming practices and environmental pressures. Only recently have studies started to consider the complexity of these processes instead of simply describing diversity for breeding purposes. A first step in that aim is to add multiple references to the collection of genetic data, including the farmers’ varietal taxonomy and practices and the historical background of the crop. Results On the basis of interview data collected in a previous study, we sampled 166 populations of durum wheat varieties in two traditional Moroccan agrosystems, in the Pre-Rif and Atlas Mountains regions. Using a common garden experiment, we detected a high phenotypic variability on traits indicative of taxonomical position and breeding status, namely spike shape and plant height. Populations often combined modern (short) with traditional-like (tall) statures, and classical durum squared spike shape (5 flowers/spikelet) with flat spike shape (3 flowers/ spikelet) representative of primitive domesticated tetraploid wheat (ssp. dicoccum). By contrast, the genetic diversity assessed using 14 microsatellite markers was relatively limited. When compared to the genetic diversity found in a large collection of tetraploid wheat, it corresponded to free-threshing tetraploid wheat. Within Morocco, the two studied regions differed for both genetic diversity and variety names. Within regions, neither geography nor variety names nor even breeding status constituted strong barriers to gene exchange despite a few significant patterns. Conclusions This first assessment of morphological and genetic diversity allowed pointing out some important factors that may have influenced the structure and evolutionary dynamics of durum wheat in Morocco: the significance of variety names, the occurrence of mixtures within populations, the relative strength of seed exchange between farmers and local adaptation, as well as the fate of modern varieties once they have been introduced. Further, multidisciplinary studies at different spatial scales are needed to better understand these complex agrosystems of invaluable importance for food security. Electronic supplementary material The online version of this article (doi:10.1186/s12862-014-0264-2) contains supplementary material, which is available to authorized users.

Much of the worlds' annual harvest loss to pests and diseases occurs as a consequence of crops grown in monocultures, or crop varieties with uniform resistance. This uniform resistance is met by the continuing evolution of new races of pests and pathogens that are able to overcome resistance genes introduced by modern breeding, creating the phenomenon of boom and bust cycles. Until recently, IPM methods have concentrated on using agronomic techniques to modify the environment around predominantly modern cultures to reduce the need for pesticides, making limited use of the opportunities offered by the effective deployment of the intra-specific diversity of local crop varieties themselves within IPM practices. One of the few assets available to small-scale farmers in developing countries to reduce pest and disease damage is their local crop varietal diversity, together with the knowledge to manage and deploy this diversity appropriately. Through a research partnership, over the past eight years, among Biodiversity International and over 30 national and local government and non-government organizations in China, Uganda, Ecuador, and Morocco, high levels of diversity were found within the traditional varieties of a set of globally agreed upon staple crops for the specific pest and disease systems in the four countries: (i) maize (Zea mays): northern leaf blight (Setosphaeria turcica) and stem borer; (ii) common bean (Phaseolus vulgaris): angular leaf spot (Phaeoisariopsis griseola), anthracnose (Colletotrichum lindemuthianum), rust (Uromyces appendiculatus), and bean fly (Ophiomyia phaseoli; O. spencerella); (iii) faba bean (Vicia faba): aphids (Aphis fabae), chocolate spot (Botrytis fabae), seed pod weevil (Bruchus rufimanus; B. dentipes); (iv) banana and plantain (Musa spp.): black leaf streak (black sigatoka; Mycosphaerella fijiensis), Fusarium wilt (Fusarium oxysporum f. sp. cubense), nematodes, and weevils (Cosmopolites sordidus); (v) barley (Hordeum vulgaris): net blotch (Pyrenophora teres) and powdery mildew (Blumeria graminis); and (vi) rice (Oryza sativa): rice blast (Pyricularia grisea) and rice plant hopper (Nilaparvata lugens). Resistance of traditional and modern varieties to the above pests and diseases was assessed from both participatory diagnostics of farmer knowledge and from cross-site on-farm and on-station trials. By performing cross-site onfarm experiments, it was possible to identify traditional varieties with more effective resistance to pest and diseases when grown outside their home sites in all four countries. Increased diversity of crop varieties, measured by number of varieties (richness) and their evenness of distribution across the farmer's fields corresponded to a decrease in the average damage levels across sites and to a reduction of variance of disease damage for common bean and plantain in Uganda, and for maize and rice in China. In sites with greater disease incidence in Uganda, households with greater levels of diversity in their production systems had less damage to their standing crop in the field compared to sites with lower disease incidence. The results support what might be expected of a risk-minimizing strategy for use of diversity to reduce pest and disease damage.