Genetic diversity among North African faba bean landraces for competitive ability against weeds

Die genetische Diversität marokkanischer Ackerbohnen (Vicia faba L.) sollte zur Verbesserung der Konkurrenzkraft von Ackerbohnen gegen Unkraut genutzt werden. Das Ziel dieser Arbeit war die detaillierte Evaluierung der Konkurrenzkraft und Produktivität einer Sammlung marokkanischer Ackerbohnen-Landrassen gegenüber dem Modell­unkraut Sinapis alba. Sechzig marokkanische Ackerbohnen-Landrassen und zwei Standards wurden 2011 und 2013 auf Kornertrag und weitere agronomische Merkmale untersucht, mit und ohne Modellunkraut, in einer Spaltanlage unter Feldbedingungen an zwei Orten im Nordwesten Marokkos. Die Landrassen zeigten signifikante genetische Variation für Produktivität und Konkurrenzkraft. Mehrere Landrassen erreichten höhere Werte als die Standards. Der Ertragsverlust durch den Unkrautstress betrug im Mittel 69%, der Unkraut-Konkurrenz-Index betrug im Mittel rund 1,28. Die Landrassen × Unkraut-Interaktion für Ertrag war eine hoch signifikante und bedeutende Variationsursache. Einige Landrassen kombinierten eine hohe Konkurrenzkraft gegen das Modell­unkraut mit überlegener Produktivität.The genetic diversity of Moroccan faba bean (Vicia faba L.) landraces should be exploited to improve the competitive ability of faba beans against weeds. The objective of this study was to in-detail evaluate competitive ability and productivity of a collection of Moroccan faba bean landraces relative to a model weed, Sinapis alba. Sixty Moroccan faba bean landraces and two checks were evaluated in 2011 and 2013 for grain yield and further agronomic traits, with and without model weed stress, under field conditions at two locations in the northwest of Morocco, using a split-plot design. The landraces showed significant genetic variation for producti­vity and competitive ability. Several landraces exhibited higher values compared to the two checks. Yield loss attributable to weed stress was, on average, about 69%; the weed competitive index was, on average, about 1.28. Land­races × weed treatment interaction for yield was a highly significant and marked source of variation. Several landraces were found to combine high levels of both, competitive ability against the model weed and productivity

Towards a comprehensive characterization of durum wheat landraces in Moroccan traditional agrosystems: analysing genetic diversity in the light of geography, farmers’ taxonomy and tetraploid wheat domestication history

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

Impact du relief et des circuits semenciers locaux sur la diversité agro-morphologique du blé dur (Triticum turgidum ssp. durum) dans la vallée d'Er Rich à Imilchil (Maroc)

Phenotypic diversity of 101 durum wheat landrace populations collected from the oasis of the Oriental Atlas Mountains (Morocco) was studied. Nine characters (morphological and agronomic) were measured on the 3030 lines (30 lines per population). The frequencies of each phenotypic class were used for the estimate and the analysis of diversity, by considering the geographical zones of origin and the gradients of altitude. The Shannon-Weaver diversity index (H’) showed a wide variability for all considered traits. This index varies from one area to another and from one altitudinal class to another. The mean H’ recorded for all areas was 0.62, indicating the presence of a high degree of polymorphism among the studied durum wheat landrace populations. The results of the multiple component analysis and the hierarchical clustering showed that the geographical proximity and altitude play a main function in the discrimination and the structure of the studied durum wheat populations. The information gathered from this study could be used in conventional breeding programs and in situ conservation of the diversity. La diversité phénotypique de 101 populations locales de blé dur issues des oasis de montagnes de l’Atlas oriental (Maroc) a été étudiée. Neuf caractères (morphologiques et agronomiques) ont été mesurés sur les 3030 lignées (30 lignées par population). Les fréquences de chaque classe phénotypique ont été utilisées pour l’estimation et l’analyse de la diversité, en considérant les zones géographiques d’origine et les gradients d’altitude. L’indice de diversité de Shannon-Weaver (H’) a montré une forte variabilité pour l’ensemble des caractères considérés. Cet indice varie d’une zone à une autre et d’une classe d’altitude à une autre. Le H’ moyen obtenu pour l’ensemble des zones est de 0,62, indiquant la présence d’un degré élevé de polymorphisme au sein des populations locales de blé dur collectées. Les résultats de l’analyse en composantes multiples ainsi que de la classification hiérarchique ont montré que la proximité géographique et l’altitude jouent un rôle majeur dans la discrimination ainsi que sur la structuration des populations de blé dur étudiées. Les informations recueillies à partir de ces résultats peuvent être exploitées dans des programmes de sélection conventionnels et de conservation in situ de la diversité. Mots clés: Populations locales, diversité phénotypique, structuration, conservation in situ, blé dur (Triticum turgidum ssp. durum)

Analyse de la tolérance des populations locales de fève (Vicia faba L.) à la sécheresse au stade juvénile

Drought is the most important abiotic stress responsible of the production instability and lower levels of yields of faba bean (Vicia faba L.). The cropping of tolerant varieties can be an opportunity to stabilize production. The objective of the present study was to evaluate the genetic variability and to study the drought tolerance in the juvenile plant stage in a collection of local Moroccan faba bean populations from the province of Taounate. A number of 60 local populations were studied under controlled conditions in a greenhouse. Different morphological and physiological traits were studied before and under water stress and during the recovery phase. The difference between recovery and water stress phases estimates the capacity of local populations to recover from drought. The local populations contain a wide diversity for different studied traits. The gain in dry matter has a negative and highly significant correlation with dry matter yield under water stress (r = -0.64 **). The populations 16, 47, 1 and 9 have proven to be the most drought tolerant at juvenile stage

Impact du relief et des circuits semenciers locaux sur la diversité agro-morphologique du blé dur (Triticum turgidum ssp. durum) dans la vallée d’Er Rich – Imilchil (Maroc)

Phenotypic diversity of 101 durum wheat landrace populations collected from the oasis of the Oriental Atlas Mountains (Morocco) was studied. Nine characters (morphological and agronomic) were measured on the 3030 lines (30 lines per population). The frequencies of each phenotypic class were used for the estimate and the analysis of diversity, by considering the geographical zones of origin and the gradients of altitude. The Shannon-Weaver diversity index (H’) showed a wide variability for all considered traits. This index varies from one area to another and from one altitudinal class to another. The mean H’ recorded for all areas was 0.62, indicating the presence of a high degree of polymorphism among the studied durum wheat landrace populations. The results of the multiple component analysis and the hierarchical clustering showed that the geographical proximity and altitude play a main function in the discrimination and the structure of the studied durum wheat populations. The information gathered from this study could be used in conventional breeding programs and in situ conservation of the diversity

Diversité agro-morphologique et gestion variétale par les agriculteurs du blé dur (Triticum turgidum ssp. durum) dans le Pré-Rif marocain

Le blé dur est une culture stratégique au Maroc. La caractérisation et l’évaluation des variétés cultivées dans différents agro-écosystèmestraditionnels permettent la sauvegarde et la réhabilitation de ce patrimoine génétique ainsi que son utilisation dans desprogrammes de sélection. Dans ce contexte, une collection de 59 populations traditionnelles de blé dur issues de la région du Pré-Rif a été étudiée en utilisant neuf traits agro-morphologiques. La diversité phénotypique a été déterminée par l’indice de diversitéShannon-Weaver (H’) à différents niveaux (Totalité de l’échantillon, par typologie du blé et par nom variétal). Les H’ estimés ontmontré une large variabilité phénotypique pour les différents traits avec un H’ moyen de 0,78. Les résultats de l’analyse des correspondancesmultiples et de la classification hiérarchique ont montré une nette distinction entre les variétés modernes et traditionnelles.Les caractères agro-morphologiques ne permettent pas de différencier les variétés traditionnelles entre elles. Les résultats de ce travailont permis de révéler la grande diversité phénotypique des variétés de blé dur qui ne correspond que partiellement aux noms desvariétés du fait de l’existence d’homonymes et de synonymes dans les noms donnés par les agriculteurs.Durum wheat is a strategic crop in Morocco. Characterization and evaluation of cultivated varieties in different traditional agroecosystemsallows safeguard and rehabilitation of this genetic heritage and its use in breeding programs. In this context, a collectionof 59 traditional populations of durum wheat from the Pre-Rif region was studied using nine agro-morphological traits. Phenotypicdiversity was determined by the Shannon-Weaver diversity index (H’) at different levels (totality of sample, by type of wheat andvarietal names). Estimated H’ showed a wide genetic variability for different traits with a mean of H’=0.78. The results of the multiplecorrespondence analysis and hierarchical clustering showed a clear distinction between modern and traditional varieties. In traditionalvarieties, agro-morphological traits do not differentiate between varieties. The results of this work revealed the great phenotypic andnominative diversity of durum wheat varieties as well as the existence of homonyms and synonyms in the names given by farmers

Anchoring durum wheat diversity in the reality of traditional agricultural systems: varieties, seed management, and farmers’ perception in two Moroccan regions

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

Seedling and adult stage resistance to net form of net blotch (NFNB) in spring barley and stability of adult stage resistance to NFNB in Morocco

International audienceThis 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 <= 0.05) across all seven environments. Specifically, two stable genotypes, AM-187 and AM-244, had lower mean NFNB severities across all environments, suggesting a quantitative resistance in these genotypes. Divergent environmental responses of NFNB severity were measured in Sidi El Ayedi 2015 and Sidi Allal Tazi 2016, suggesting that these environments may be suitable to capture resistance to diverse pathotypes. These stable genotypes are valuable resources for introgression of both qualitative resistance and quantitative resistance to NFNB in future

A global perspective of the richness and evenness of traditional crop-variety diversity maintained by farming communities

Varietal data from 27 crop species from five continents were drawn together to determine overall trends in crop varietal diversity on farm. Measurements of richness, evenness, and divergence showed that considerable crop genetic diversity continues to be maintained on farm, in the form of traditional crop varieties. Major staples had higher richness and evenness than nonstaples. Variety richness for clonal species was much higher than that of other breeding systems. A close linear relationship between traditional variety richness and evenness (both transformed), empirically derived from data spanning a wide range of crops and countries, was found both at household and community levels. Fitting a neutral “function” to traditional variety diversity relationships, comparable to a species abundance distribution of “neutral ecology,” provided a benchmark to assess the standing diversity on farm. In some cases, high dominance occurred, with much of the variety richness held at low frequencies. This suggested that diversity may be maintained as an insurance to meet future environmental changes or social and economic needs. In other cases, a more even frequency distribution of varieties was found, possibly implying that farmers are selecting varieties to service a diversity of current needs and purposes. Divergence estimates, measured as the proportion of community evenness displayed among farmers, underscore the importance of a large number of small farms adopting distinctly diverse varietal strategies as a major force that maintains crop genetic diversity on farm