PREVALENCE OF ANGULAR LEAF SPOT DISEASE AND SOURCES OF RESISTANCE IN COMMON BEAN IN EASTERN DEMOCRATIC REPUBLIC OF CONGO

Angular leaf spot ( Pseudocercospora griseola Crous U, Brown) is one of the most important diseases hindering common bean ( Phaseolus vulgaris L.) production in the Great Lakes Region of Africa, including the Democratic Republic of Congo. The disease causes extreme yield losses, estimated at 384.2 tonnes per year, in Sub-Saharan Africa. Little is known about the distribution, severity and incidence of the disease and the effect of agronomic practices and environmental factors on the disease prevalence in the country to facilitate interventions. A field survey was conducted during two crop seasons, February to June and September to January, in two main beans growing zones of eastern DRC namely; sub-humid highland and sub-humid mid altitude at low latitudes, in South and North Kivu, respectively. Severity and incidence of angular leaf-spot and other occurring diseases were assessed on common bean plants in farmers\u2019 fields. Angular leaf spot in these fields had an average severity index (PSI) of 49.9%. PSI was significantly different (P<0.05) between districts and seasons. Using multiple regression analysis, independent variables: growth stage, cropping system, districts and altitude were shown to have significant influence on the observed PSI (P<0.05) with R2 = 96.2%. The highest severity (PSI=59.7%) was observed in Kabare district, and the lowest in Uvira district (PSI=39.5%). Screening of a set of 37 released common bean varieties in DRC using virulent Andean and Mesoamerican isolates identified four resistant bean varieties; ARA 4, COD MLV 059, MLV 224/94B, LSA 144 and Mexico 54. Some of these varieties possess useful traits, in addition to acceptable seed market class, and are hence recommended as suitable parents for ALS resistant variety development and promotion in ALS prone environments.La tache angulaire ( Pseudocercospora griseola Crous U, Brown) est l\u2019une des maladies les plus importantes qui entravent la production de haricot commun ( Phaseolus vulgaris L.) dans la r\ue9gion des Grands Lacs d\u2019Afrique, y compris la R\ue9publique D\ue9mocratique du Congo. La maladie provoque des pertes de rendement extr\ueames, estim\ue9es \ue0 384.2 tonnes par an en Afrique Sub-Saharienne. Ily a encore peu de connaissance sur la distribution, la gravit\ue9 et l\u2019incidence de la maladie et l\u2019effet des pratiques agronomiques et des facteurs environnement aux sur la pr\ue9valence de la maladie dans le pays pour faciliter les interventions. Une enqu\ueatesur le terrain a \ue9t\ue9men\ue9e pendant deux saisons de r\ue9colte, de F\ue9vrier \ue0 Juin et de Septembre \ue0 janvier, dans deux zones principals de culture de haricots de l\u2019est de la RDC, \ue0 savoir: Sous-humides de haute altitude et sous-humides \ue0 basse altitude, au Sud et au Nord-Kivu. La gravit\ue9 et l\u2019incidence de la tache angulaire des feuilles et d\u2019autres maladies ont \ue9t\ue9 \ue9valu\ue9es sur les plants de haricots dans les champs des agriculteurs. Ces champs \ue9taient infest\ue9s par la maladie, avec unindice de gravit\ue9 moyen (IPS) de 49.9%. PSI \ue9tait significativement diff\ue9rent (P <0.05) entre districts et saisons. En utilisant l\u2019analyse de r\ue9gression multiple, les variables ind\ue9pendantes: stade de croissance, syst\ue8me de culture, districts et altitude ont montr\ue9 une influence significative sur le PSI observ\ue9 (P <0.05) avec R2 = 96.2%. La s\ue9v\ue9rit\ue9 plus \ue9lev\ue9e (PSI = 59.7%) a \ue9t\ue9 observ\ue9e dans le district de Kabare et la plus faible dans le district d\u2019Uvira (PSI = 39,5%). La s\ue9lection d\u2019un lot de 37 vari\ue9t\ue9s de haricot distribu\ue9es en RDC utilisant des isolats virulents Andins et M\ue9soam\ue9ricains a permis d\u2019identifier quatre vari\ue9t\ue9s de haricots r\ue9sistants; ARA 4, COD MLV 059, MLV 224 / 94B, LSA 144 et Mexique 54. Certaines de ces vari\ue9t\ue9s pr\ue9sentent des traits utiles en plus de son acceptabilit\ue9 sur lemarch\ue9 des semences, et sont donc recommand\ue9s comme des parents appropri\ue9s pour le d\ue9veloppement et la promotion des vari\ue9t\ue9s r\ue9sistantes ALS

Distribution of common bacterial blight disease under different agroecologies in Uganda

Common bacterial blight disease (CBB) causes severe yield and seed quality losses on common bean worldwide. Information about CBB distribution is important in designing effective control strategies. This disease has been managed using intergraded strategies, involving use of certified seed produced in areas of low disease pressure. Unfortunately, areas of low CBB pressure have not been mapped in Uganda. This study was conducted to determine the distribution and intensity of CBB in Uganda, in order to establish low pressure areas for multiplication of clean certified seed. A survey was conducted in farmers\u2019 fields in18 locations found in four rainfalls-based agroecology in Uganda, for two seasons of 2016. The Victoria Cresent and Mbale farmland had the highest disease intensity index (29%); followed by Central woodland savannah (21%). The Northwest farm land and South west grass farm lands had low CBB intensity index of 2.5 and 7.8%, respectively. Thus, The Northwest farm land (Arua, Amuru, Nwoya) and South west grass farm lands (Rakai, Ntungamo Lwengo and Bukomansimbi), are recommended for production of CBB free bean seeds.La maladie bact\ue9rienne commune (MBC) provoque de graves pertes de rendement et de qualit\ue9 des semences de haricot commun dans le monde entier. Les informations sur la distribution du MBC sont importantes pour la conception de strat\ue9gies de contr\uf4le efficaces. Cette maladie a \ue9t\ue9 g\ue9r\ue9e \ue0 l\u2019aide de strat\ue9gies intercal\ue9es, impliquant l\u2019utilisation de semences certifi\ue9es produites dans des zones de faible pression de la maladie. Malheureusement, les zones de faible pression du CBB n\u2019ont pas \ue9t\ue9 cartographi\ue9es en Ouganda. Cette \ue9tude a \ue9t\ue9 faite pour d\ue9terminer la distribution et l\u2019intensit\ue9 du CBB en Ouganda, afin d\u2019\ue9tablir des zones de basse pression pour la multiplication de semences certifies qui sont propres. Une enqu\ueate a \ue9t\ue9 faite dans les champs d\u2019agriculteurs dans 18 localit\ue9s situ\ue9es dans quatre agro\ue9cologies en Ouganda bas\ue9es sur les pr\ue9cipitations, pendant les deux saisons de 2016. Les terres agricoles de Victoria Cresent et de Mbale pr\ue9sentaient l\u2019indice d\u2019intensit\ue9 de maladie le plus \ue9lev\ue9 (29%); suivi de la savane bois\ue9e centrale (21%). Les terres agricoles du nord-ouest et celles du sud-ouest avaient un indice d\u2019intensit\ue9 de CBB faible de 2,5 et 7,8%, respectivement. Ainsi, les terres agricoles du Nord-Ouest (Arua, Amuru, Nwoya) et celles du Sud-Ouest (Rakai, Ntungamo Lwengo et Bukomansimbi) sont recommand\ue9es pour la production de semences de haricot exemptes de CBB

Development and delivery of bean varieties in Africa: The Pan- Africa Bean Research Alliance (PABRA) Model

Common bean ( Phaseolus vulgaris L.) has evolved rapidly in Africa and is steadily transforming from a traditional subsistence to a market-oriented crop, with major impacts on household incomes, food and nutritional security, and national economies. However, these benefits are yet to be felt in many parts of the continent because of multiple constraints that limit bean productivity. The Pan-Africa Bean Research Alliance (PABRA) has been at the forefront of efforts to accelerate the transition of beans from a subsistence crop to a modern commodity in Sub-Saharan Africa. This paper presents a unique partnership model and the breeding and seed delivery strategies used by PABRA to reach millions of beneficiaries with improved bean varieties. The breeding strategy involved the paradigm shift from a monolithic approach where varieties were bred for yield or resistance to single environmental stresses, to a grain type-led and market-driven approach. The PABRA model comprises partnerships between and among Centro Internacional de Agricultura Tropical (CIAT), National Agricultural Research Systems (NARS), public and private sector actors along the varied bean product value chains, and technology end-users. This model led to the release of over 200 varieties during 2003-2011, including beans with resistance to multiple constraints (biotic and abiotic), high iron and zinc content, and those for specific niche markets. PABRA reached 7.5 million households with seed of improved bean varieties during 2003- 2008 and is expected to reach an additional 14 million by 2013. From this undertaking, aspects that lend to policy recommendations to key stakeholders in the common beans value chain include: facilitation of access to credit; promotion of breeder and foundation seed production; easing of restrictions on the release of varieties; facilitation of collective marketing schemes; and deliberate policy frameworks to encourage the use of complementary integrated crop management practices.En Afrique, le haricot commun ( Phaseolus vulgaris L.) a connu une \ue9volution rapide se transformant d\u2019une culture de subsistance traditionnelle en une marchandise commerciale avec des impacts majeurs sur les revenus, la s\ue9curit\ue9 alimentaire et nutritionnelle des m\ue9nages ainsi que sur l\u2019\ue9conomie nationale. Toutefois, ces avantages ne sont pas tellement per\ue7us dans nombreuses r\ue9gions du continent en raison de multiples contraintes (biotiques et abiotiques) qui limitent la rentabilit\ue9 et la commercialisation du haricot. L\u2019Alliance Panafricaine de Recherche sur l\u2019Haricot (PABRA - Pan Africa Bean Research Alliance) est \ue0 l\u2019avant-garde des efforts visant acc\ue9l\ue9rer cette transition du haricot en Afrique sub-saharienne. Cet article pr\ue9sente un mod\ue8le de partenariat unique, et les strat\ue9gies de s\ue9lection et vulgarisation des vari\ue9t\ue9s utilis\ue9es par PABRA pour faciliter l\u2019acc\ue8s des millions de b\ue9n\ue9ficiaires aux vari\ue9t\ue9s am\ue9lior\ue9es du haricot. La strat\ue9gie de s\ue9lection exigeait le changement d\u2019une approche monolithique o\uf9 les vari\ue9t\ue9s \ue9taient s\ue9lectionn\ue9es pour leur rendement ou leur r\ue9sistance aux stress environnementaux simples, \ue0 une approche bas\ue9e sur le type de grain et ax\ue9e sur le march\ue9. Le mod\ue8le de PABRA comprend les partenariats entre et parmi le Centre International d\u2019Agriculture Tropical(CIAT), les syst\ue8mes nationaux de recherche agricole (NARS), les acteurs publics et priv\ue9s le long des diff\ue9rentes cha\ueenes de valeur du haricot, et les utilisateurs de nouvelles technologies. Ce mod\ue8le a conduit \ue0 l\u2019enregistrement de plus de 200 vari\ue9t\ue9s durant la p\ue9riode 2003-2011, y compris les haricots avec r\ue9sistance \ue0 multiples contraintes (biotiques et abiotiques), un contenu \ue9lev\ue9 de fer (Fe) et du zinc (Zn), et ceux pour les march\ue9s de niches sp\ue9cifiques. PABRA a atteint 7,5 millions de m\ue9nages facilitant leur acc\ue8s aux semences de vari\ue9t\ue9s am\ue9lior\ue9es de haricots durant la p\ue9riode 2003 2008 et devrait atteindre quelque 14 millions de personnes suppl\ue9mentaires d\u2019ici 2013. Les recommandations aux d\ue9cideurs politiques qui visent \ue0 renforcer le d\ue9veloppement et la vulgarisation des vari\ue9t\ue9s am\ue9lior\ue9es du haricot comprennent: la facilitation de l\u2019acc\ue8s au cr\ue9dit; promotion de la production de semences de base et pr\ue9-base; assouplissement des restrictions sur la diffusion des vari\ue9t\ue9s; facilitation des r\ue9gimes de commercialisation collective; et des cadres de politique visant \ue0 encourager la gestion int\ue9gr\ue9e des cultures chez les cultivateurs de haricot

Multiple disease resistance in snap bean genotypes in Kenya

Snap bean ( Phaseolus vulgaris L.) is an important export vegetable crop, produced mainly by small to medium scale farmers under various disease constraints. Disease resistant varieties can reduce reliance on fungicides, and enhance the capacities of smallholder farmers to meet the stringent European export requirements for allowable fungicide residues. This study was carried out to identify snap bean lines with multiple disease resistance to angular leaf spot ( Phaeoisareopsis griseola ), anthracnose ( Collectotrichum lindemuthianum ) and rust ( Uromyces appendiculatus ). Seven groups of snap bean populations of different generations, and 45 bush snap bean lines, including local checks, were evaluated for resistance to the three diseases at two locations in Kenya. The disease with the highest severity was rust, followed by angular leaf spot. Among the advanced lines, two bush lines (KSB 10 W and KSB 10 BR), and one climbing line (HAV 130) had consistent multiple resistance to angular leaf spot, anthracnose and rust at both locations. Nine lines and 674 single plants were selected from populations showing multiple disease resistance. Resistance in selected lines reduced angular leaf spot, anthracnose and rust severity by 17, 16 and 36%, respectively. The multiple disease resistant lines were not the highest yielders but had the highest number of pods per plant. Climbing snap bean lines had thick pods that could reduce pod quality.Le haricot vert ( Phaseolus vulgaris L.) est une importante l\ue9gume d\u2019exportation, produite principalement par de petits fermiers sous diff\ue9rentes contraintes de maladies. Des vari\ue9t\ue9s r\ue9sistantes aux maladies peuvent r\ue9duire l\u2019utilisation de fongicides, et promouvoir la capacit\ue9 des petits fermiers \ue0 satisfaire les exigencies rigoureuses des exportations europ\ue9ennes en r\ue9sidus acceptables de fongicides. Cette \ue9tude \ue9tait m\ue9n\ue9e afin d\u2019identifier des lign\ue9es de haricots verts avec multiple r\ue9sistance \ue0 la t\ue2che angulaire des feuilles ( Phaeoisareopsis griseola ), \ue0 l\u2019anthracnose ( Collectotrichum lindemuthianum ) et \ue0 la rouille ( Uromyces appendiculatus ). Sept groupes de populations de diff\ue9rentes g\ue9n\ue9rations, et 45 lign\ue9es de haricots verts nains incluant les t\ue9moins locaux, \ue9taient \ue9valu\ue9s pour r\ue9sistance aux trois maladies dans deux localisations au Kenya. La maladie avec une s\ue9v\ue9rit\ue9 la plus \ue9lev\ue9e \ue9tait la roulle, suivie par la t\ue2che angulaire des feuilles. Parmi les lign\ue9es avanc\ue9es, deux lign\ue9es naines (KSB 10 W et KSB 10 BR), et une volubile (HAV 130) avaient une resistance multiple consistante \ue0 la t\ue2che angulaire des feuilles, \ue0 l\u2019anthracnose et \ue0 la rouille dans toutes les deux localisations. Neuf lign\ue9es et 674 plantes simples s\ue9lectionnn\ue9es des populations avaient montr\ue9 une r\ue9sistance multiple aux maladies. La r\ue9sistance dans les lign\ue9es s\ue9lectionn\ue9es avaient r\ue9duit la s\ue9verit\ue9 de la t\ue2che angulaire des feuilles, de l\u2019anthracnose et de la rouille de 17, 16 et 36%, respectivement. Les lign\ue9es de r\ue9sistance multiple n\u2019avaient pas des rendements plus \ue9lev\ue9s mais avaient un nombre plus \ue9lev\ue9 de gousses par plante. Les lign\ue9es de haricots verts volubiles avaient des gousses \ue9paisses susceptibles \ue0 r\ue9duire la qualit\ue9 de gousses

PABRA means partnership: Transforming agriculture in Africa together

For two decades, the Pan-Africa Bean Research Alliance (PABRA), a partnership developed and facilitated by the International Center for Tropical Agriculture (CIAT) – a CGIAR Research Center – has fostered a pan-African research and development partnership to strengthen the common bean value chain. Common beans are important food legumes and contribute to the food and nutrition security, income generation and enhances production systems in over 32 countries in sub-Saharan Africa. To achieve food and nutrition security, Africa must participate, promote regional, continental, and global markets, and strengthen key value chains. Our policies need to be deliberately tailored, made conducive and supportive so as to take advantage of opportunities offered by technological development and innovations. Enhancing capacities of different stakeholder cannot be emphasized. With a changing climate, Africa needs to be prepared with mitigation strategies, plans, policies, tools and actions that enhance resilience of our production systems and communities

The draft genome sequence of Xanthomonas species strain Nyagatare, isolated from diseased bean in Rwanda.

types: Journal ArticleThis is a pre-copyedited, author-produced PDF of an article accepted for publication in FEMS following peer review. The version of record Aritua, V., Musoni, A., Kabeja, A., Butare, L., Mukamuhirwa, F., Gahakwa, D., . . . Smith, J. (2015). The draft genome sequence of Xanthomonas species strain Nyagatare, isolated from diseased bean in Rwanda, FEMS Microbiology Letters, 2015, Vol. 362, No. 4 pp. 1-4 is available online at: http://femsle.oxfordjournals.org/content/362/4/1.1.exploreWe announce the genome sequence for Xanthomonas species strain Nyagatare, isolated from beans showing unusual disease symptoms in Rwanda. This strain represents the first sequenced genome belonging to an as-yet undescribed Xanthomonas species known as species-level clade 1. It has at least 100 kb of genomic sequence that shows little or no sequence similarity to other xanthomonads, including a unique lipopolysaccharide synthesis gene cluster. At least one genomic region appears to have been acquired from relatives of Agrobacterium or Rhizobium species. The genome encodes homologues of only three known type-three secretion system effectors: AvrBs2, XopF1 and AvrXv4. Availability of the genome sequence will facilitate development of molecular tools for detection and diagnostics for this newly discovered pathogen of beans and facilitate epidemiological investigations of a potential causal link between this pathogen and the disease outbreak.Canadian International Development AgencyBBSRC SCPRI

Pathogenicity and virulence of Ugandan isolates of common bacterial blight disease pathogen ( Xanthomonas spp.)

Breeding for resistance is a major component in the integrated management of common bacterial disease of beans ( Phaseolus vulgaris L.). Use of less virulent strains or strains with attenuated virulence may lead to selection of resistant genotypes with intermediate response, when exposed to more virulent strains of the pathogen. The objective of this study to identify and characterise Ugandan isolates of common bacterial blight disease-causing pathogens for virulence. Bacteria were isolated from leaf samples collected from districts of Kabale, Masaka, Bukomansimbi, Mubende, Mbale, Bulambuli and Apac, all in Uganda, during the first season of 2016. The bacteria were tested for pathogenicity, as well as virulence on both breeding and local varieties. The study identified three most virulent isolates, namely MBL020, KAB-3 and BUL-14, all belonging to Xathomonas citri pv fuscans. These isolates are very similar to those previously identified from Uganda (NCPB 670 and NCCPB 1402) more than 50 years ago. The study further revealed that NAROBEAN1, NAROBEAN 2, NAROBEAN 4, VAX 3, VAX5 and NE 2- 14- 8 had better resistance compared to other tested genotypes.La s\ue9lection pour la r\ue9sistance est un \ue9l\ue9ment majeur de la gestion int\ue9gr\ue9e des maladies bact\ue9riennes courantes des haricots ( Phaseolus vulgaris L.). L\u2019utilisation de souches moins virulentes ou de souches \ue0 virulence att\ue9nu\ue9e peut conduire \ue0 la s\ue9lection de g\ue9notypes r\ue9sistants \ue0 r\ue9ponse interm\ue9diaire, lorsqu\u2019ils sont expos\ue9s \ue0 des souches plus virulentes du pathog\ue8ne. L\u2019objectif de cette \ue9tude etait d\u2019identifier et de caract\ue9riser les isolats ougandais de pathog\ue8nes causant la maladie bact\ue9rienne commune pour la virulence. Des bact\ue9ries ont \ue9t\ue9 isol\ue9es \ue0 partir d\u2019\ue9chantillons de feuilles pr\ue9lev\ue9s dans les districts de Kabale, Masaka, Bukomansimbi, Mubende, Mbale, Bulambuli et Apac, tous en Ouganda, au cours de la premi\ue8re saison de 2016. Les bact\ue9ries ont \ue9t\ue9 test\ue9es pour leur pathog\ue9nicit\ue9, ainsi que leur virulence \ue0 la fois pour la reproduction et vari\ue9t\ue9s locales. L\u2019\ue9tude a identifi\ue9 les trois isolats les plus virulents, \ue0 savoir MBL020, KAB-3 et BUL-14, tous appartenant \ue0 Xathomonas citri pv fuscans. Ces isolats sont tr\ue8s similaires \ue0 ceux pr\ue9c\ue9demment identifi\ue9s en Ouganda (NCPB 670 et NCCPB 1402), il y a plus de 50 ans. L\u2019\ue9tude a en outre r\ue9v\ue9l\ue9 que NAROBEAN1, NAROBEAN 2, NAROBEAN 4, VAX 3, VAX5 et NE 2- 14-8 avaient une meilleure r\ue9sistance par rapport aux autres g\ue9notypes test\ue9s

PARTNERSHIPS IN HIGHLANDS OF RWANDA UNDER INTEGRATED AGRICULTURAL RESEARCH FOR DEVELOPMENT (IAR4D) ARRANGEMENTS

The Integrated Agricultural Research for Development (IAR4D) concept was proposed to respond to the failures of Agriculture Research and Development (ARD) systems in Sub-Saharan Africa. The key element of implementation and success of IAR4D was action sites called agricultural Innovation Platform (IPs) and their counterfactual sites. Social Network Analysis (SNA) is used to explain social relationships and partnerships. This study explored the patterns of agricultural partnerships among stakeholders in the highlands of Rwanda under IAR4D. Data were collected in action sites that included Mudende, Gataraga, Remera and Rwerere; and in their counterpart counterfactual sites that comprised of Bigogwe, Nyange and Gacaca. Results showed that in action sites, stakeholders were linked to different and diversified partners. Furthermore, many stakeholders were connected to several partners through agricultural partnerships, hence creating complex social networks with high density and degree of distribution. In the counterfactual sites, however, stakeholders were exclusively linked to the same kind of partners, and one stakeholder was connected to one partner through probably non-agricultural partnerships. These facts demonstrated that IAR4D created dense interfaces, significantly improved the networking system, and delivered technologies and innovations.Le concept de Recherche Agricole Int\ue9gr\ue9e pour le D\ue9veloppement (IAR4D) a \ue9t\ue9 propos\ue9 comme solution aux \ue9checs des syst\ue8mes Recherches Agricoles et D\ue9veloppement (ARD) en Afrique Sub-Saharienne. L\u2019\ue9l\ue9ment principal de la r\ue9ussite et du succ\ue8s d\u2019IAR4D \ue9tait l\u2019\ue9tablissement des sites d\u2019action appel\ue9s Plateformes Agricoles d\u2019innovation (IPs) ainsi que leurs sites t\ue9moins. L\u2019analyse du R\ue9seau Sociale (SNA) est utilis\ue9e pour expliquer les rapports et les relations sociaux des acteurs et des partenaires. La pr\ue9sente \ue9tude avait pour objectif d\u2019explorer les structures des relations socio-agricoles parmi les acteurs et les partenaires dans les hautes altitudes du Rwanda soumises \ue0 l\u2019IAR4D. Les donn\ue9es ont \ue9t\ue9 r\ue9colt\ue9es dans les sites d\u2019action comprenant\ua0: Mudende, Gataraga, Remera et Rwerere ainsi que dans leurs contreparties sites t\ue9moins incluant Bigogwe, Nyange et Gacaca. Les r\ue9sultats ont montr\ue9 que dans les sites d\u2019action, les acteurs \ue9taient associ\ue9s aux partenaires de natures diff\ue9rentes et un acteur \ue9tait li\ue9 \ue0 plusieurs partenaires a la fois. Dans les sites t\ue9moins par contre, les acteurs \ue9taient li\ue9s aux partenaires de m\ueames natures que ceux-ci et un acteur \ue9tait rarement li\ue9 \ue0 plus de deux partenaires. Ces faits ont montr\ue9 que l\u2019IAR4D a cr\ue9e un r\ue9seau socio-agricole tr\ue8s dense et sophistiqu\ue9 et ainsi a consid\ue9rablement am\ue9lior\ue9 le r\ue9seau socio-agricole. Par cons\ue9quent, l\u2019IAR4D peut \ueatre recommand\ue9 pour le transfert the technologies and des innovations agricoles