AfricaRice Publications

Diversité génétique des variétés de NERICAs et des variétés « interspécifiques » (Oryza glaberrima x O. sativa) de bas-fonds et étude du déterminisme génétique de la compétitivité des variétés de riz vis – à – vis des mauvaises herbes

Africa Rice Center — Fri, 25 May 2012 12:56:12 +0000

Pages: 234.

Yonnelle Déa MOUKOUMBI et al.

Rice is a major staple food for Sub-Saharan African population. The creation of the new rice varieties: New Rice for Africa (NERICA) has increased rice production in Sub Saharan Africa. Theses varieties combine the potential of their two parents and are also cultivated in different cropping systems. The current research studies lowland NERICAs and « promising lines » genetic diversity and genetic determinism of rice weed competitiveness. The agromorphological characterization used experimental design an augmented randomized complete block, 23 agro-morphological traits were collected and during two consecutive seasons at Ouedémé. On the other hand, 74 (SHAWHON/WAB56-50) and 120 (TOGIR64/IR64) SSR markers was used to evaluate the proportion of African parental genomic contribution to plant material. The screening of fourteen parental using a split plot design with 3 weeding regimes (0, 1 and 4 weeding), 3 types of the traits and genetic analysis from F1, F2, BC1F1 and BC2F1 population was realized to understand the genetic determinism rice weed competitiveness. Tillering at 60 days after sowing (DAS), plant height at maturity, maturity and spikelet fertility were the most discriminate and could therefore supplement a wide range of variables for phenotypic diversity study. Lowland NERICAs and promising lines varieties were grouped in cluster 1 containing the desired characters adapted to lowland rice cultivation and the entries were grouped into three clusters irrespective of the level of backcrossing of genotypes. The estimated average O. glaberrima genome coverage was 11% (BC2), 6.07% (BC3) and 7.55% (BC4) and the highest proportion of O. glaberrima genome was observed on Chromosomes 2 (BC2), 6 (BC3) and 12 (BC4). An introgression rate of 15.31% was observed in promising lines. The determination of broad sense heritability showed three types of heritable traits and the dominant weed species were Acanthospermum hispidum, Dactyloctenium aegyptium and Digitaria horizontalis. The variety CG20 of the African species was selected as the most competitive variety. The statistical model used has revealed that the dominant effects are higher than additive effects except for the high in the crosses. Additionally, high xiv These de Doctorat de l’Universite d’Abomey-Calavi Spécialité : Ressources Phytogénétiques et Protection des Cultures additive variances and broad sense heritability were obtained from CG20 x FKR19 cross. These results represent the interesting research perspectives for a better management of genetic diversity of plant material studied and a better understanding of genetic determinism of rice weed competitiveness and answering consumer’s expectation.

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Agricultural trade for food security in Africa: A Ricardian model approach

Africa Rice Center — Tue, 22 May 2012 08:18:02 +0000

International Association of Agricultural Economists (2012). Pages: 1-46.

Mandiaye Diagne, Steffen Abele, Aliou Diagne, Papa A. Seck et al.

Regionalism and food security is a relatively neglected topic with very limited literature. We use a Ricardian trade model with multiple goods and countries which embeds a structure of gravity equation and yield variability. Our study shows that integration with African markets of staple foods is associated with higher growth, underpinning the need for growth strategies to emphasize scaling up and diversifying exports within Africa. Africa needs to unlock its high potential untapped land and fill up the yield gap. We found as well that enhanced competitiveness and reduced barriers to trade are the two critical areas of action.

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Improving irrigated rice production in the Senegal River Valley through experiential learning and innovation

Africa Rice Center — Fri, 18 May 2012 16:53:15 +0000

Agricultural Systems (2012). Pages: 101-112.

Timothy J. Krupnik, Carol Shennan, William H. Settle, Matty Demont, Alassane B. Ndiaye, Jonne Rodenburg et al.

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Morpho-agronomic evaluation of Oryza glaberrima accessions and interspecific O. sativa × O. glaberrima derived lines under drought conditions

Africa Rice Center — Fri, 18 May 2012 16:51:29 +0000

AFRICAN JOURNAL OF AGRICULTURAL RESEEARCH (2012). Volume: 7, Issue: 16.

Marie Noelle NDJIONDJOP, Koichi FUTAKUCHI, Papa Abdoulaya SECK, Fousseyni CISSE, Roland BOCCO, Blandine FATONDJI et al.

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First Report of Rice yellow mottle virus on Rice in Burundi

Africa Rice Center — Wed, 02 May 2012 07:24:27 +0000

Plant Disease (2012). Pages: 120425140502006.

Innocent Ndikumana, Agnes Pinel-Galzi, Zenna Négussié, Susan N’chimbi Msolla, P Njau, Rakesh Kumar Singh, Il-Ryong Choi, Joseph Bigirimana, Denis Fargette, Eugenie Hébrard et al.

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Effect of fungi–termite interaction on the chlorophyll content of three rice varieties grown on ultisol soil of Ikenne, south-west Nigeria

Africa Rice Center — Thu, 26 Apr 2012 08:04:45 +0000

Archives Of Phytopathology And Plant Protection (2012). Pages: 1-12.

Olumoye E. Oyetunji, Cecilia O. Peluola, Francis E. Nwilene, Gbenga Akinwale, Abou Togola, Tolulope A. Agunbiade, Abiodun O. Claudius-Cole et al.

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Evaluation of Al-tolerance on upland and lowland types of NERICA lines under hydroponic conditions

Africa Rice Center — Fri, 20 Apr 2012 07:58:13 +0000

Journal of Crop Science and Biotechnology (2012). Volume: 15, Issue: 1. Pages: 25-31.

Dong-Jin Kang, Koichi Futakuchi, Young-Jin Seo, Pisoot Vijarnsorn, Ryuichi Ishii et al.

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Improving irrigated rice production in the Senegal River Valley through experiential learning and innovation

Africa Rice Center — Thu, 19 Apr 2012 18:10:16 +0000

Agricultural Systems (2012). Pages: 101-112.

Timothy J. Krupnik, Carol Shennan, William H. Settle, Matty Demont, Alassane B. Ndiaye, Jonne Rodenburg et al.

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Introduction to Selected Articles from the Second Africa Rice Congress (2010)

Africa Rice Center — Thu, 19 Apr 2012 13:44:24 +0000

Crop Science (2012). Volume: 52, Issue: 2. Pages: 482-483.

P.A. Seck, B. Témé et al.

The Second Africa Rice Congress was held in Bamako, Mali, from 22 to 26 Mar. 2010 under the aegis of the Malian government. It was co-organized by the Africa Rice Center (AfricaRice) and the Institut d’économie rurale (IER) with the theme “Innovation and Partnerships to Realize Africa’s Rice Potential.”

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Enhancing Rice Productivity in West Africa through Genetic Improvement

Africa Rice Center — Thu, 19 Apr 2012 13:44:24 +0000

Crop Science (2012). Volume: 52, Issue: 2. Pages: 484-493.

K. Saito, Y. Sokeia, M.C.S. Wopereis et al.

Rice yields have stagnated in West Africa at 1 to 2 Mg ha−1 because of unfavorable rice environments and poor management practices. Interspecific rice cultivars, the New Rice for Africa (NERICA), were developed by crossing Asian rice (Oryza sativa L.) and African rice (O. glaberrima Steud.) to improve upland and lowland rice productivity in resource-poor farmers’ fields. This paper provides an overview of recent studies, performed by the Africa Rice Center and its partners, on evaluation of growth and yield performance of upland and lowland NERICA cultivars and modern Asian rice cultivars including the improved upland indica cultivars often termed aerobic rice. Upland NERICA cultivars were found to lack the expected combination of superior yield potential with weed suppressive ability (WSA) and adaptation to low soil fertility, instead sharing similarity in these characteristics with their O. sativa parent WAB56-104 but remaining inferior to their O. glaberrima parent CG 14 in terms of tillering ability and WSA. Some aerobic rice cultivars were identified for high yielding ability, strong WSA, and superior adaptation to low-fertility uplands and water-limited lowlands. Some lowland NERICA cultivars outyielded improved lowland O. sativa checks and aerobic rice cultivars in favorable lowlands, whereas they did not perform well in water-limited lowlands. The implications of these findings for future challenges for genetic improvement in West Africa are discussed.

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Field Evaluation of Rice Genotypes from the Two Cultivated Species (Oryza sativa L. and Oryza glaberrima Steud.) and Their Interspecifics for Tolerance to Drought

Africa Rice Center — Thu, 19 Apr 2012 13:43:14 +0000

Crop Science (2012). Volume: 52, Issue: 2. Pages: 524-538.

Marie Noelle Ndjiondjop, Koichi Futakuchi, Fousseyni Cisse, Hugues Baimey, Roland Bocco et al.

A total of 327 rice (Oryza spp.) genotypes were screened for tolerance to drought at the Africa Rice Center in Cotonou, Benin, in 2007 and 2008. Plants were subjected to full irrigation from sowing to harvest or to 21-d drought from 34 d after sowing. Drought-affected plants showed narrower leaves, reduced grain yield, and shorter stature. Tillering and plant maturity were negatively affected by drought whereas values for leaf temperature and leaf greenness were significantly higher under drought than under control condition. Under control condition, for 54% of genotypes, flowering occurred between 71 and 90 d after sowing. But under drought, flowering occurred at 90 or more days after sowing for the majority of genotypes. Significant genotype × environment interactions were observed for plant height, leaf greenness, flowering, grain yield, maturity, leaf rolling, and leaf tip burning. More traits were correlated with grain yield under drought for Oryza glaberrima Steud. than for other genotype groups. No relationship was observed between plant recovery ability and all other traits selected. More than 90% of plants evaluated resumed growth after drought in both years. TOG6208, TOG5691, TOG5591, TOG6594, and RAM122 were identified as best performing genotypes in terms of grain yield under drought. Their performance was similar to that of most of the 24 top yielding in terms of leaf rolling, leaf tip burning, and plant recovery after drought release.

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Multienvironment Quantitative Trait Loci Mapping and Consistency across Environments of Resistance Mechanisms to Ferrous Iron Toxicity in Rice

Africa Rice Center — Thu, 19 Apr 2012 13:43:14 +0000

Crop Science (2012). Volume: 52, Issue: 2. Pages: 539-550.

I. Dufey, M.-P. Hiel, P. Hakizimana, X. Draye, S. Lutts, B. Koné, K.N. Dramé, K.A. Konaté, M. Sie, P. Bertin et al.

Lowland rice (Oryza sativa L.) is often affected by iron toxicity, which may lead to yield losses. One important constraint in the study of the inheritance of resistance strategies to this stress is the inconsistency of gene expression across different environments. This study aimed to determine the stability of quantitative trait loci (QTL) across several environments. Quantitative trait loci mapping for traits related to resistance mechanisms had been previously performed using 164 recombinant inbred lines derived from ‘Azucena’ and ‘IR64’ screened in hydroponics in a phytotron. In the present study, this population was tested under excessive ferrous iron conditions in three additional environments: in hydroponics in a greenhouse, on washed sand, and in the field. Altogether, 44 putative QTL were identified in the four single QTL analyses for morphological, physiological, and agronomic traits. From these 44 QTL, 20 were found in overlapping regions for the same or related traits in different environments, identifying six genomic regions of great interest for the inheritance of resistance to iron toxicity. Quantitative trait loci stability across environments was also checked by performing a joint QTL analysis, which confirmed the position of nine QTL previously found in the same or adjacent regions by at least one single analysis. Combining both single and joint analyses helps in separating QTL specific to a particular environment from generally expressed ones thus is more suitable for marker-assisted selection.

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Multivariate Analysis of Diversity of Landrace Rice Germplasm

Africa Rice Center — Thu, 19 Apr 2012 13:43:14 +0000

Crop Science (2012). Volume: 52, Issue: 2. Pages: 494-504.

K.A. Sanni, I. Fawole, A. Ogunbayo, D. Tia, E. Somado, K. Futakuchi, M. Sié, F.E. Nwilene, R.G. Guei et al.

Multivariate analysis is based on a statistical principle involving observation and analysis of more than one statistical variable at a time. The variability of 434 accessions of rice (Oryza sativa L.) germplasm from Côte d’Ivoire was evaluated for 10 agro-morphological traits in upland conditions at M’bé, Côte d’Ivoire (7°5′ N, 5°1′ W) in 2002 using augmented experimental design and analyzed with multivariate methods. The unweighted pair group method of the average linkage (UPGMA) cluster analysis, canonical discriminant analysis, and principal component analysis (PCA) were used to analyze the data obtained. This enabled the assessment of the extent and pattern of variation of the germplasm and identification of the major traits contributing to the diversity. Seven cluster groups were obtained from the 10 agro-botanical traits using the UPGMA. Canonical discriminant analysis showed the contribution of each trait to the classification of the rice accessions into different cluster groups. The first three principal components explained about 72.4% of the total variation among the 10 characters. The results of canonical discriminant analysis and PCA suggested that traits such as plant height, leaf length, number of days to heading and maturity, tillering ability, and grain size (weight, length, width, and shape) were the principal discriminatory characteristics. It was concluded that variation exists in the germplasm, which provides opportunities for this collection to be useful for genetic improvement.

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Rôles des légumineuses sur la fertilité des sols

Africa Rice Center — Thu, 19 Apr 2012 08:05:22 +0000

Editions universitaires europeennes (2012). Pages: 188.

Boubié Vincent Bado, André Bationo, Michel Cescas et al.

Les coûts élevés et le difficile accès aux engrais limitent les rendements des cultures et la production agricole en particulier chez les petits producteurs à faibles revenus. Les cultures légumineuses fixatrices d’azote sont des alternatives pour améliorer la nutrition azotée et la fertilité des sols. Deux légumineuses (l'arachide et le niébé) couramment cultivées par les producteurs peuvent fixer jusqu’à 56 kg/ha d’azote dans l’atmosphère, une source d’azote partiellement recyclable dans le sol par les résidus de cultures. La fixation symbiotique de l’azote est accrue par la fertilisation des légumineuses avec des amendements organiques et minéraux locaux comme les phosphates naturels. Les légumineuses augmentent l’azote du sol, l’efficacité d’utilisation de l’azote apporté par les engrais et la culture suivante prélève 2 à 3 fois plus d’azote, entraînant des augmentations de rendements de 60 à 300 %. Une gestion intégrée des engrais, des amendements locaux et des légumineuses offre des opportunités pour améliorer la fertilité et la productivité des systèmes de cultures.

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Comprehensive gene expression analysis of the NAC gene family under normal growth conditions, hormone treatment, and drought stress conditions in rice using near-isogenic lines (NILs) generated from crossing Aday Selection (drought tolerant) and IR64

Africa Rice Center — Thu, 19 Apr 2012 07:44:01 +0000

Molecular Genetics and Genomics (2012).

Mohammed Nuruzzaman, Akhter Most Sharoni, Kouji Satoh, Ali Moumeni, Ramiah Venuprasad, Rachid Serraj, Arvind Kumar, Hei Leung, Kotb Attia, Shoshi Kikuchi et al.

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Yield, water productivity and nutrient balances under the System of Rice Intensification and Recommended Management Practices in the Sahel

Africa Rice Center — Mon, 09 Apr 2012 11:17:54 +0000

Field Crops Research (2012). Pages: 155-167.

Timothy J. Krupnik, Carol Shennan, Jonne Rodenburg et al.

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Représentation de la pluie dans les modèles régionaux de climat et application à l’estimation des rendements du mil au Sénégal

Africa Rice Center — Mon, 02 Apr 2012 13:23:09 +0000

Secheresse (2012). Pages: 14-23.

S. Salack, B. Sultan, P. Oettli, B. Muller, AT. Gaye, F. Hourdin et al.

Les très fortes répercussions des aléas climatiques sur l’agriculture et la sécurité alimentaire en Afrique subsaharienne, auxquelles se rajoute la perspective du changement climatique, ont poussé la communauté scientifique à documenter les impacts du climat dans cette région. Cependant, si la plupart des études quantifiant les impacts du climat se basent sur des sorties de modèles régionaux de climat, très peu font part de l’incertitude associée à leur utilisation. Pourtant le choix d’un modèle régional plutôt qu’un autre, voire même d’une paramétrisation plutôt qu’une autre, peut influer fortement sur le résultat final car les modèles agronomiques sont très sensibles à la qualité du forçage climatique en entrée. L’objectif de cette étude est d’explorer cette question en analysant la dispersion de la représentation des pluies issues d’un ensemble de huit modèles régionaux et la façon dont cette dispersion se traduit dans l’estimation des rendements du mil au Sénégal, simulés par le modèle agronomique SARRAH. L’étude montre qu’il existe une grande dispersion dans la représentation de la pluviométrie d’un modèle régional à l’autre (et même pour un même modèle régional avec deux jeux de paramètres différents) tant à l’échelle saisonnière qu’à l’échelle intrasaisonnière. Ces biais introduisent des erreurs importantes dans l’estimation des impacts agronomiques. Ces erreurs peuvent être à même d’invalider des conclusions sur les impacts du changement climatique basés sur l’utilisation d’un seul modèle régional. L’utilisation de méthodes de correction de biais s’avère ainsi indispensable.

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Overview of Long Term Experiments in Africa

Africa Rice Center — Wed, 28 Mar 2012 15:20:47 +0000

Lessons learned from Long-term Soil Fertility Management Experiments in Africa (2012). Pages: 1-26.

A. Bationo, B. Waswa, A. Abdou, B. V. Bado, M. Bonzi, E. Iwuafor, C. Kibunja, J. Kihara, M. Mucheru, D. Mugendi, J. Mugwe, C. Mwale, J. Okeyo, A. Olle, K. Roing, M. Sedogo et al.

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Simulation of Potential Yields of New Rice Varieties in the Senegal River Valley

Africa Rice Center — Wed, 28 Mar 2012 15:20:47 +0000

Improving Soil Fertility Recommendations in Africa using the Decision Support System for Agrotechnology Transfer (DSSAT) (2012). Pages: 141-155.

Michiel E. Vries, Abdoulaye Sow, Vincent B. Bado, Nomé Sakane et al.

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Long Term Effects of Crop Rotations with Fallow or Groundnut on Soil Fertility and Succeeding Sorghum Yields in the Guinea Savannah of West Africa

Africa Rice Center — Wed, 28 Mar 2012 15:20:47 +0000

Lessons learned from Long-term Soil Fertility Management Experiments in Africa (2012). Pages: 27-40.

B. V. Bado, A. Bationo, F. Lompo, K. Traore, M. P. Sedogo, M. P. Cescas et al.

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