Sahelian Center

Niamey, Niger

Sahelian Center

Niamey, Niger
SEARCH FILTERS
Time filter
Source Type

Subbarao G.V.,Japan International Research Center for Agricultural science | Sahrawat K.L.,Indian International Crops Research Institute for the Semi Arid Tropics | Nakahara K.,Japan International Research Center for Agricultural science | Rao I.M.,Centro Internacional Of Agricultura Tropical Ciat | And 6 more authors.
Annals of Botany | Year: 2013

BackgroundAgriculture is the single largest geo-engineering initiative that humans have initiated on planet Earth, largely through the introduction of unprecedented amounts of reactive nitrogen (N) into ecosystems. A major portion of this reactive N applied as fertilizer leaks into the environment in massive amounts, with cascading negative effects on ecosystem health and function. Natural ecosystems utilize many of the multiple pathways in the N cycle to regulate N flow. In contrast, the massive amounts of N currently applied to agricultural systems cycle primarily through the nitrification pathway, a single inefficient route that channels much of this reactive N into the environment. This is largely due to the rapid nitrifying soil environment of present-day agricultural systems.ScopeIn this Viewpoint paper, the importance of regulating nitrification as a strategy to minimize N leakage and to improve N-use efficiency (NUE) in agricultural systems is highlighted. The ability to suppress soil nitrification by the release of nitrification inhibitors from plant roots is termed 'biological nitrification inhibition' (BNI), an active plant-mediated natural function that can limit the amount of N cycling via the nitrification pathway. The development of a bioassay using luminescent Nitrosomonas to quantify nitrification inhibitory activity from roots has facilitated the characterization of BNI function. Release of BNIs from roots is a tightly regulated physiological process, with extensive genetic variability found in selected crops and pasture grasses. Here, the current status of understanding of the BNI function is reviewed using Brachiaria forage grasses, wheat and sorghum to illustrate how BNI function can be utilized for achieving low-nitrifying agricultural systems. A fundamental shift towards ammonium (NH4 +)-dominated agricultural systems could be achieved by using crops and pastures with high BNI capacities. When viewed from an agricultural and environmental perspective, the BNI function in plants could potentially have a large influence on biogeochemical cycling and closure of the N loop in crop-livestock systems. © 2012 The Author.


PubMed | University of Texas at Austin, Sahelian Center, Kansas State University, Cornell University and 4 more.
Type: Journal Article | Journal: Science advances | Year: 2015

Improving environmental adaptation in crops is essential for food security under global change, but phenotyping adaptive traits remains a major bottleneck. If associations between single-nucleotide polymorphism (SNP) alleles and environment of origin in crop landraces reflect adaptation, then these could be used to predict phenotypic variation for adaptive traits. We tested this proposition in the global food crop Sorghum bicolor, characterizing 1943 georeferenced landraces at 404,627 SNPs and quantifying allelic associations with bioclimatic and soil gradients. Environment explained a substantial portion of SNP variation, independent of geographical distance, and genic SNPs were enriched for environmental associations. Further, environment-associated SNPs predicted genotype-by-environment interactions under experimental drought stress and aluminum toxicity. Our results suggest that genomic signatures of environmental adaptation may be useful for crop improvement, enhancing germplasm identification and marker-assisted selection. Together, genome-environment associations and phenotypic analyses may reveal the basis of environmental adaptation.


Wildemeersch J.C.J.,Ghent University | Garba M.,INRAN | Sabiou M.,INRAN | Fatondji D.,Sahelian Center | Cornelis W.M.,Ghent University
Soil Science and Plant Nutrition | Year: 2015

Abstract: Whether aggravated agricultural drought in the Sahel is related to a changing climate (meteorological drought, i.e., deficit of rainfall or unfavourable rainfall distribution) or to land use and land degradation (soil-water drought, i.e., decreased water infilitration and water holding capacity) is a much-debated issue. Global climate models and trend analysis show little agreement on how rainfall and meteorological drought are changing in the region, and research has increasingly attributed agricultural drought to an imbalanced rainwater distribution over the root zone caused by human-induced land degradation. This paper investigates the extent of both meteorological and soil-water drought on “laterite” soils in the Tillaberí region of Niger and their effect on millet (Pennisetum glaucum (L.) R. Br.) growth by combining monthly (1905–1996) and daily (1989–2010) rainfall analysis with analysis of the root zone water distribution under different management practices. The treatments include: zaï + manure (Z), demi-lunes + manure (DL), scarification + manure (SCAR), control + manure (CF) and control (C). Our findings suggest that increasing agricultural drought does not originate from a decreasing annual amount of rainfall. However, other daily rainfall parameters more important for crop biomass productivity than total rainfall amount, such as the number of dry spells, do appear to have recently worsened. Dry-spell analysis showed increased drought risks during the vegetative growth phase (0–40 DAS) and the vulnerable grain formation phase (90–110 DAS, Days After Sowing). The extremely low grain yields and values of soil-water storage below the critical value for water stress of the control treatments, moreover, confirm poor root zone water distribution. DL and Z however, show potential, to mitigate both dry spells and soil-water drought, as they induce an important increase of soil-water storage, resulting in higher grain yields. In order to optimize these water and soil conservation (WSC) techniques and to increase their potential for drought mitigation, the underlying features enabling increased soil-water storage, including water balance analysis, soil physical properties, nutrient management and system design, should be tackled in future studies. © 2015 Japanese Society of Soil Science and Plant Nutrition.


Upadhyaya H.D.,Indian International Crops Research Institute for the Semi Arid Tropics | Dwivedi S.L.,Indian International Crops Research Institute for the Semi Arid Tropics | Vadez V.,Indian International Crops Research Institute for the Semi Arid Tropics | Hamidou F.,Sahelian Center | And 4 more authors.
Crop Science | Year: 2014

Peanut (Arachis hypogaea L.) is extensively grown by resource-poor farmers in the semiarid tropics where many abiotic and biotic stresses limit the crop's productivity and seed quality. Peanut cultivars with enhanced host-plant resistance, adaptation to abiotic stress, input-use efficiency, and yield potential will maximize yield gains and minimize inputs to sustain production. The peanut mini core collection was evaluated for agronomic traits in multienvironment trials at Patancheru, India. The published information on 184 mini core accessions revealed 28 accessions resistant to abiotic stress, 30 resistant to biotic stress, and 18 that were agronomically desirable but susceptible to stresses, while 16 were seed nutrient dense. The mini core is part of the composite collection, which was previously genotyped using SSRs. The agronomic evaluation, stress response, and nutritional information together with genotyping data were used to identify genetically diverse germplasm with agronomically beneficial traits: ICG 12625 (resistance to drought, low temperature, late leaf spot [LLS], Aspergillus flavus Link, bacterial wilt; high oil and good oil quality) and ICG 442 (resistance to drought, salinity, P deficiency); ICG 12625 and ICG 2381 (resistance to rust, A. flavus; good oil quality); ICG 12697 (resistance to LLS, rust, A. flavus) and ICG 6022 (resistance to early leaf spot [ELS], LLS); ICG 14710 (high oil, Fe, Zn) and ICG 7963 (high protein, Fe, Zn); ICG 11426 (resistance to ELS, LLS, rust) and ICG 5221 (high Fe and Zn and good oil quality). Accessions with adaptation to rainy and/or post-rainy environments were ICG# 434, 5745, 8285, 10036, 11088, 11651, 12625, 15042, and 15419. These accessions are ideal genetic resources that may be used to develop agronomically superior and nutritionally enhanced peanut cultivars with multiple resistances to abiotic and biotic stresses. © Crop Science Society of America.


Ramu P.,Indian International Crops Research Institute for the Semi Arid Tropics | Ramu P.,Osmania University | Billot C.,CIRAD - Agricultural Research for Development | Rami J.-F.,CIRAD - Agricultural Research for Development | And 5 more authors.
Theoretical and Applied Genetics | Year: 2013

Selection and use of genetically diverse genotypes are key factors in any crop breeding program to develop cultivars with a broad genetic base. Molecular markers play a major role in selecting diverse genotypes. In the present study, a reference set representing a wide range of sorghum genetic diversity was screened with 40 EST-SSR markers to validate both the use of these markers for genetic structure analyses and the population structure of this set. Grouping of accessions is identical in distance-based and model-based clustering methods. Genotypes were grouped primarily based on race within the geographic origins. Accessions derived from the African continent contributed 88.6 % of alleles confirming the African origin of sorghum. In total, 360 alleles were detected in the reference set with an average of 9 alleles per marker. The average PIC value was 0.5230 with a range of 0.1379-0.9483. Sub-race, guinea margaritiferum (Gma) from West Africa formed a separate cluster in close proximity to wild accessions suggesting that the Gma group represents an independent domestication event. Guineas from India and Western Africa formed two distinct clusters. Accessions belongs to the kafir race formed the most homogeneous group as observed in earlier studies. This analysis suggests that the EST-SSR markers used in the present study have greater discriminating power than the genomic SSRs. Genetic variance within the subpopulations was very high (71.7 %) suggesting that the germplasm lines included in the set are more diverse. Thus, this reference set representing the global germplasm is an ideal material for the breeding community, serving as a community resource for trait-specific allele mining as well as genome-wide association mapping. © 2013 Springer-Verlag Berlin Heidelberg.


Vadez V.,Indian International Crops Research Institute for the Semi Arid Tropics | Kholova J.,Indian International Crops Research Institute for the Semi Arid Tropics | Hummel G.,Phenospex | Zhokhavets U.,Phenospex | And 2 more authors.
Journal of Experimental Botany | Year: 2015

In this paper, we describe the thought process and initial data behind the development of an imaging platform (LeasyScan) combined with lysimetric capacity, to assess canopy traits affecting water use (leaf area, leaf area index, transpiration). LeasyScan is based on a novel 3D scanning technique to capture leaf area development continuously, a scanner-to-plant concept to increase imaging throughput and analytical scales to combine gravimetric transpiration measurements. The paper presents how the technology functions, how data are visualised via a web-based interface and how data extraction and analysis is interfaced through 'R' libraries. Close agreement between scanned and observed leaf area data of individual plants in different crops was found (R2 between 0.86 and 0.94). Similar agreement was found when comparing scanned and observed area of plants cultivated at densities reflecting field conditions (R2 between 0.80 and 0.96). An example in monitoring plant transpiration by the analytical scales is presented. The last section illustrates some of the early ongoing applications of the platform to target key phenotypes: (i) the comparison of the leaf area development pattern of fine mapping recombinants of pearl millet; (ii) the leaf area development pattern of pearl millet breeding material targeted to different agro-ecological zones; (iii) the assessment of the transpiration response to high VPD in sorghum and pearl millet. This new platform has the potential to phenotype for traits controlling plant water use at a high rate and precision, of critical importance for drought adaptation, and creates an opportunity to harness their genetics for the breeding of improved varieties. © 2015 The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.


Tesfamariam T.,Crop | Yoshinaga H.,Crop | Deshpande S.P.,Indian International Crops Research Institute for the Semi Arid Tropics | Srinivasa Rao P.,Indian International Crops Research Institute for the Semi Arid Tropics | And 5 more authors.
Plant and Soil | Year: 2014

Background and aims: Nitrification and denitrification are the two most important processes that contribute to greenhouse gas emission and inefficient use of nitrogen. Suppressing soil nitrification through the release of nitrification inhibitors from roots is a plant function, and termed "Biological Nitrification Inhibition (BNI)". We report here the role and contribution of sorgoleone release to sorghum-BNI function. Methods: Three sorghum genotypes (Hybridsorgo, IS41245 and GDLP 34-5-5-3) were evaluated for their capacity to release sorgoleone, which has BNI-activity, in hydroponic and soil culture. Sorgoleone released was measured using HPLC; BNI-activity was determined using a luminescent recombinant Nitrosomonas europaea assay. Results: Sorgoleone production and BNI-activity release by roots are closely associated (1 μg of sorgoleone is equivalent to 1 ATU activity in assay). Purified sorgoleone inhibited Nitrosomonas activity and suppressed soil nitrification. Sorghum genotypes release varying quantity of sorgoleone; GDLP 34-5-5-3 and Hybridsorgo showed higher capacity for both sorgoleone release and BNI-activity than did IS41245. In soil culture, GDLP 34-5-5-3 released higher quantity of sorgoleone into the rhizosphere, which had higher BNI-activity, and suppressed soil nitrification to a greater extent than did by IS41245. Conclusions: These results demonstrate genetic differences for sorgoleone release and its functional link with BNI-capacity; there is potential for genetic improvement of sorghum BNI-capacity and deployment of this in low-nitrifying sorghum production systems. © 2014 Springer International Publishing Switzerland.


Kagamebga W.F.,University of Ouagadougou | Thiombiano A.,University of Ouagadougou | Traore S.,University of Ouagadougou | Zougmore R.,Sahelian Center | Boussim J.I.,University of Ouagadougou
Annals of Forest Research | Year: 2011

Land degradation is a major problem in the Sahelian countries. Erosion control through establishment of vegetation cover is at important strategy to reverse the trend. Our research objective was to analyse the effects of three restoration techniques on Jatropha curcas L. seedlings growth and survivorship. We are conducted two separate field trials, involving the sowing and planting of J. curcas, in which several different soil restoration techniques were applied. The trial was monitored using a randomized block study design over a period of two years. The design included ten different treatments, six in the sowing trial and four in the planting trial, each with three replicates. In the first experiment, growth rate was found to be significantly higher in the Sub-Soiling treatment, that received additional organic matter than other treatments. However, overall survival rate was low (18%). In the second experiment, the Half-moon treatment yielded a significantly higher growth both in height (df = 3, F = 56.74, p < 0.05) and diameter (df = 3, F = 31.76, p < 0.05) and survival rate compared to those of the other treatments (df = 3, F = 50.4, p < 0.05). In conclusion, planting seedlings produced a greater survival rate than sowing seeds. Among the soil restoration and water conservation techniques tested in this study, the Half-moon technique was found to be the most effective. This is recommended to be used for improving the revegetation of J. curcas in the future.


Bielders C.L.,Catholic University of Louvain | Gerard B.,Sahelian Center
Field Crops Research | Year: 2015

Soil fertility is a major constraint to agricultural development in most of the Sahel, with P being the most limiting nutrient for millet production on acid sandy soils. To address this issue, microdose applications of P fertilizer have been widely advocated in recent years. However, little is known regarding the effect of farmer management practices and environmental factors on millet's yield response to this technique. For this purpose, 276 farmer demonstrations were setup across a 3-year period in the Fakara region, western Niger. Five strata were considered based on antecedent organic manure management (corralling or transported manure). At each demo site, conventional management was compared to basal microdose fertilizer application of DAP (2ghill-1), NPK (6ghill-1), or DAP (2ghill-1) with urea (1ghill-1) applied at tillering. Millet grain yields on control plots were low (84%<400kgha-1), reflecting the unfavorable environmental conditions of the area. On average, the application of DAP, NPK and DAP+urea increased grain yields by 43, 46 and 69kgha-1 (2001-2002). A positive response to microdose fertilization was observed for 92% of the sites where yields on control plots were <100kgha-1 but only for 32% of the sites where yields on control plots were >500kgha-1. In particular, the positive response to microdosing increased with later sowing given that late sowing tended to reduce yields on control plots. Higher rainfall during the early growing season favored a positive response to microdosing. On average over DAP and DAP+urea, 36% of the demonstrations had value-cost ratios (VCR)<1. However, for low yielding control plots (<200kggrainha-1), 26% of the demonstrations had VCR<1, whereas for high yielding plots (>400kggrainha-1), 55% had a VCR<1. Not accounting for labor, DAP and DAP+urea had similar economic returns. The use of NPK could not be recommended as the cost per unit P is 3 times higher than DAP. It appears that, for the Fakara study area, microdosing may best be targeted to areas with low expected yields. In particular, it may serve as a famine mitigation strategy in case of late sowing. Nevertheless, for poorly endowed areas such as the Fakara, the economic risk associated with microdosing (2gDAPhill-1) appears higher than has hitherto been reported and widespread adoption may not be warranted without institutional support. © 2014 Elsevier B.V.


PubMed | Sahelian Center, Indian International Crops Research Institute for the Semi Arid Tropics and Phenospex
Type: Journal Article | Journal: Journal of experimental botany | Year: 2015

In this paper, we describe the thought process and initial data behind the development of an imaging platform (LeasyScan) combined with lysimetric capacity, to assess canopy traits affecting water use (leaf area, leaf area index, transpiration). LeasyScan is based on a novel 3D scanning technique to capture leaf area development continuously, a scanner-to-plant concept to increase imaging throughput and analytical scales to combine gravimetric transpiration measurements. The paper presents how the technology functions, how data are visualised via a web-based interface and how data extraction and analysis is interfaced through R libraries. Close agreement between scanned and observed leaf area data of individual plants in different crops was found (R(2) between 0.86 and 0.94). Similar agreement was found when comparing scanned and observed area of plants cultivated at densities reflecting field conditions (R(2) between 0.80 and 0.96). An example in monitoring plant transpiration by the analytical scales is presented. The last section illustrates some of the early ongoing applications of the platform to target key phenotypes: (i) the comparison of the leaf area development pattern of fine mapping recombinants of pearl millet; (ii) the leaf area development pattern of pearl millet breeding material targeted to different agro-ecological zones; (iii) the assessment of the transpiration response to high VPD in sorghum and pearl millet. This new platform has the potential to phenotype for traits controlling plant water use at a high rate and precision, of critical importance for drought adaptation, and creates an opportunity to harness their genetics for the breeding of improved varieties.

Loading Sahelian Center collaborators
Loading Sahelian Center collaborators