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Ouattara B.,Center Detudes Regional Pour Lamelioration Of Ladaptation Secheresse Ceraas | Ndir K.N.,University Of Thies | Gueye M.C.,Center Detudes Regional Pour Lamelioration Of Ladaptation Secheresse Ceraas | Diedhiou I.,University Of Thies | And 5 more authors.
Genetic Resources and Crop Evolution | Year: 2014

Significant efforts have been undertaken in West Africa to increase biofuel production with the expectation to alleviate the dependency on fossil energies and to reduce rural poverty by diversifying cultivated crops. In this context, Jatropha curcas L., a shrub belonging to Euphorbiaceae family, has gained great interest because of its oil which can be converted to biodiesel. It is also highly adaptable to marginal soils due to its drought-tolerant characteristics. Characterisation of J. curcas germplasm in Senegal could be an important input for its better management and in identifying genotypes that could be used in breeding program. Genetic diversity of 103 accessions including 82 accessions from different agro ecological zones in Senegal and 21 exotic accessions was assessed through 33 microsatellite markers. All the markers gave amplifications at the expected band size. Only one microsatellite marker, JCT17, was polymorphic showing 3 alleles and allows distinguishing 2 accessions from Burkina Faso. The surprisingly low level of genetic variation might be because introduction of J. curcas in Senegal seems to have been done from one or a few origins and the species has not regained genetic diversity since then due to vegetative propagation. Cultivation of J. curcas at large scale may face to vulnerability to pests and require many cautions. They are necessity to widen the genetic base of J. curcas in Senegal via new introductions from its centre of origin. © 2014 Springer Science+Business Media Dordrecht.

Dossa K.,Chinese Academy of Agricultural Sciences | Dossa K.,Center Detudes Regional Pour Lamelioration Of Ladaptation Secheresse Ceraas | Wei X.,Chinese Academy of Agricultural Sciences | Zhang Y.,Chinese Academy of Agricultural Sciences | And 7 more authors.
Genes | Year: 2016

Sesame is an important oil crop widely cultivated in Africa and Asia. Understanding the genetic diversity of accessions from these continents is critical to designing breeding methods and for additional collection of sesame germplasm. To determine the genetic diversity in relation to geographical regions, 96 sesame accessions collected from 22 countries distributed over six geographic regions in Africa and Asia were genotyped using 33 polymorphic SSR markers. Large genetic variability was found within the germplasm collection. The total number of alleles was 137, averaging 4.15 alleles per locus. The accessions from Asia displayed more diversity than those from Africa. Accessions from Southern Asia (SAs), Eastern Asia (EAs), and Western Africa (WAf) were highly diversified, while those from Western Asia (WAs), Northern Africa (NAf), and Southeastern Africa (SAf) had the lowest diversity. The analysis of molecular variance revealed that more than 44% of the genetic variance was due to diversity among geographic regions. Five subpopulations, including three in Asia and two in Africa, were cross-identified through phylogenetic, PCA, and STRUCTURE analyses. Most accessions clustered in the same population based on their geographical origins. Our results provide technical guidance for efficient management of sesame genetic resources in breeding programs and further collection of sesame germplasm from these different regions. © 2016 by the authors; licensee MDPI, Basel, Switzerland.

Tovignan T.K.,Center Detudes Regional Pour Lamelioration Of Ladaptation Secheresse Ceraas | Fonceka D.,Center Detudes Regional Pour Lamelioration Of Ladaptation Secheresse Ceraas | Fonceka D.,CIRAD - Agricultural Research for Development | Ndoye I.,Cheikh Anta Diop University | And 2 more authors.
Field Crops Research | Year: 2016

The combined production of grain and sugar by sorghum requires efficient leaf C acquisition (source) and allocation to productive sinks, namely the stem and the panicle. Photoperiod sensitivity, which regulates plant phenology and growth, is also likely to be a key regulator of such C source-sink relationships, while it is crucial to drought adaptation. This study set out to evaluate the contribution of plant leaf area and stem growth to the production of grain and sugar by sweet, photoperiodic sorghum depending on the sowing date and post-flowering water availability. Twelve West African accessions were studied in the field in Senegal during two consecutive rainy seasons, comparing two sowing dates and post-anthesis water regimes (irrigated, or not). Plant growth and development were monitored weekly up to flowering. Organ size and biomass, stem juiciness and sweetness were characterized at flowering and maturity. At flowering, early sowing enhanced plant leaf area, stem dry weight and sugar production, and plant leaf area expressed per unit of stem dry weight was positively correlated to stem sweetness, suggesting that a high pre-flowering source-to-sink ratio favors early sugar accumulation. Overall, a late sowing date reduced sugar and grain production more than post-anthesis drought, whereas early sowing enhanced both types of production. No post-anthesis competition was found between grain filling and stem sugar accumulation. However, under drought conditions, the maintenance of combined production was better for the most leaf stay-green accessions. It is suggested that the combined production of sugar and grain by sweet, photoperiodic sorghum in response to the sowing date and post-anthesis drought is firstly sink-driven but that source (plant leaf area) dynamics can enhance stem sugar accumulation and its maintenance under drought conditions. These results provide further insight into the traits to be combined in dual-purpose ideotypes dedicated to drought-prone environments. © 2016 Elsevier B.V.

Tovignan T.K.,Center Detudes Regional Pour Lamelioration Of Ladaptation Secheresse Ceraas | Luquet D.,CIRAD - Agricultural Research for Development | Fonceka D.,CIRAD - Agricultural Research for Development | Ndoye I.,Cheikh Anta Diop University | And 2 more authors.
Plant Genetic Resources: Characterisation and Utilisation | Year: 2015

Sweet sorghum is highly coveted to contribute and take up food and energy challenges. A collection of 84 West Africa landraces mostly from Senegal and four control cultivars were screened to identify relevant accessions and trait combination for multi-purpose (sugar/grain/biomass). The implication of photoperiod sensitivity was particularly addressed. A total of 20 traits related to phenology, morphology, grain and sugar production were assessed in two sowing dates (July and August) at CNRA Bambey in Senegal. Late sowing resulted in shortened vegetative phase and a significant decrease in traits related to plant size, stem sugar, biomass and grain productions. Broad-sense heritability was moderate to high for most of the phenology, morphology, grain and sugar-related traits, suggesting their interest for breeding. All the traits related to plant size were positively correlated with plant sugar production except plant height. A cluster analysis identified three groups contrasting in their ability to combine sugar, grain or fodder production based on 18 traits measured for the early sowing. Clusters I and III were suitable for one purpose: grain and sugar, respectively. Cluster II was the most suitable for multi-purpose, showing the best trade-off among grain, sugar and vegetative biomass production. The best accessions for stem sugar yield belonged to durra, caudatum and their intermediate types. The relationship between internode size and sweetness should be further studied, in particular exploring their relationship with internode tissue anatomy. Further studies are also needed to evaluate the role that stay-green can play in sugar yield maintenance under post-flowering drought. Copyright © NIAB 2015

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