Reaction of selected common bean genotypes to physiological races of Phaeoisariopsis griseola occurring in Kenya

The wide pathogenic variability occurring in Phaeoisariopsis griseola , the causal agent of angular leaf spot of common bean ( Phaseolus vulgaris L.), dictates that new sources of resistance be continuously identified. This study was undertaken to determine the reaction of selected bean genotypes to different races of P. griseola in order to identify potential sources of resistance to angular leaf spot. Selected bean genotypes from Eastern and Central Africa Bean Research Network (ECABREN) and National Dryland Farming Research Centre (NDFRC), Katumani in Kenya were separately inoculated with forty-four races of P. griseola and evaluated for disease development under greenhouse conditions. The genotypes included small- and large-seeded types. None of the genotypes was resistant to all the races, indicating a high complexity of the pathogen population. Thirteen genotypes were resistant (disease score 1 to 3) or moderately resistant (score 4 to 6) to at least 40 of the races. Small-seeded bean genotypes ECAB 0754 and ECAB 0617 were resistant or moderately resistant to all races except Mesoamerican race 33-39 and Afro-Andean race 58-18, respectively. Genotype ECAB 0754 exhibited the highest level of resistance, with an average disease severity of 1.1%. All the resistant or moderately resistant genotypes were of the small-seeded bean types which are commercially less popular. The commonly grown large-seeded genotypes were generally susceptible. Among the bean genotypes evaluated, the small-seeded pintos and browns/yellows possessed high levels of resistance. The results of this study indicate that different bean genotypes have varying levels of resistance to angular leaf spot that can be pyramided into appropriate background to provide durable resistance.Une large variabilit\ue9 pathog\ue9nique du Phaeoisariopsis griseola , l\u2019agent causal de la t\ue2che angulaire de feuilles du haricot commun ( Phaseolus vulgaris L.), sugg\ue8re qu\u2019il y\u2019ait une identification continue de nouvelles sources de r\ue9sistance. Cette \ue9tude \ue9tait entreprise pour d\ue9terminer la r\ue9action des g\ue9notypes de haricot s\ue9lectionn\ue9s aux diff\ue9rentes races de P. griseola afin d\u2019identifier de sources potentielles de r\ue9sistance \ue0 la maladie de t\ue2che angulaire de la feuille. Les g\ue9notypes de haricot fournis par l\u2019Eastern and Central Africa Bean Research Network (ECABREN) et le National Dryland Farming Research Centre (NDFRC), Katumani au Kenya \ue9taient s\ue9par\ue9ment inocul\ue9s avec quarante-quatre races de P. griseola pour l\u2019\ue9valuation en serre du d\ue9veloppement de maladies. Les g\ue9notypes comprenaient de petits et gros grains de semences. Aucune des g\ue9notypes n\u2019\ue9tait r\ue9sistant \ue0 toutes les races de maladies, indicant ainsi une complexit\ue9 \ue9lev\ue9e de la population des pathog\ue8nes. Treize g\ue9notypes \ue9taient r\ue9sistants (\ue9chelle de cotation: 1 \ue0 3) ou mod\ue9r\ue9ment r\ue9sistants (\ue9chelle de cotation: 4 \ue0 6) sur au moins quarante de toutes les races. Les g\ue9notypes de haricot \ue0 petits grains ECAB 0754 et ECAB 0617 \ue9taient r\ue9sistants ou mod\ue9r\ue9ment r\ue9sistants \ue0 toutes les races \ue0 l\u2019exception de Mesoamerican race 33-39 et Afro-Andean race 58-18, respectivement. Le G\ue9notype ECAB 0754 avait manifest\ue9 un niveau \ue9lev\ue9 de r\ue9sistance, avec un taux moyen de s\ue9verit\ue9 de 1.1%. Tous les g\ue9notypes r\ue9sistants ou mod\ue9r\ue9ment r\ue9sistants \ue9taient de ceux \ue0 petits grains commercialement moins populaires. Les g\ue9notypes \ue0 gros grains commun\ue9ment cultiv\ue9s \ue9taient g\ue9n\ue9ralement susceptibles. Parmi les g\ue9notypes \ue9valu\ue9s, ceux \ue0 petits grains "pintos" et bruns/jaunes \ue9taient dot\ue9s des niveaux \ue9lev\ue9s de r\ue9sistance. Les r\ue9sultats de cette \ue9tude montrent que diff\ue9rents g\ue9notypes de haricot poss\ue8dent de niveaux diff\ue9rents de r\ue9sistance \ue0 la maladie de t\ue2che angulaire de la feuille pouvant \ueatre combin\ue9s par pyramidage pour d\ue9velopper une vari\ue9t\ue9 de haricot \ue0 r\ue9sistance durable

Development of an integrated bean root rot control strategy for western Kenya

Root rot severely constrains bean (Phaseolus vulgaris L.) production in parts of Western Kenya. Genetic and soil management options were evaluated for an integrated root rot management approach. Four hundred genotypes were progressively screened in the field for resistance to root not over six seasons. A sequence of problem-solving trials on cultural methods was conducted over four seasons. All trials were conducted in root rot infested fields of farmers. No resistant varieties were found in the Kenyan germplasm collection of 374 accessions. Ten resistant varieties were identified from 26 introductions which were known to be resistant to root rots in Rwanda. Farmers preferred MLB-49-89a because of its early maturity, SCAM 80-CM/5 and RWR 532 because of their high yield and seed type, and the late maturing RWR 719 as it was seen as a replacement for a previously popular cultivar which succumbed to root rots. Crop tolerance to root rots was greatly improved by improving soil fertility through application of diammonium phosphate or certain organic manures, and less so by sowing on ridges. Application of several rapidly decomposing green manures, including Tithonia diversifolia which was abundantly available in field borders, resulted in improved crop tolerance to root rot.Les pourritures racinaires constituent une contrainte majeure pour la production du haricot (Phaseolus vulgaris L.) dans certaines zones de l'Ouest du Kenya. L'utilisation du materiel genetique et la gestion du sol ont ete evaluees comme une approche de lutte integree contre ces maladies racinaires. Quatre cent genotypes etaient progressivement cribles dans le champ pour resistance sur une periode de six saisons culturales. Une serie d'essais sur les methodes culturales pour le controle de ces maladies etait conduite pendant quatre saisons. Tous les essais etaient etablis dans les champs des fermiers infestes avec les pourritures racinaires. Aucune variete n'etait trouvee resistante dans la collection du germoplasme kenyan de 374 accessions. Dix varietes etaient cependant identifiees a partir de 26 varietes introduites qui etaient anterieurement connues au Rwanda comme resistantes aux pourritures racinaires. La lignee 'MLB-49-89 A' etait preferee par les paysans a cause de sa maturite precoce; 'SCAM-80-CM/5' et 'RWR 532' preferees a cause de leur haut rendement et le type de graine; tandis que 'RWR 719' vu comme un cultivar tardif etait considere comme le remplacant d'un cultivar populaire qui a succombe anterieurement suite aux pourritures racinaires. La tolerance du haricot aux pourritures racinaires etait grandement amelioree en ameliorant la fertilite du sol par l'application de di-ammonium phosphate (DAP) ou certains fumiers organiques, et elle etait aussi moins en semant sur des billons. L'application d'engrais verts se decomposant rapidement y compris Tithonia diversifolia lequel etait abondamment disponible dans les abords des champs, a resulte dans l'amelioration de la tolerance du haricot face aux pourritures racinaires

Reaction of selected common bean genotypes to physiological races of Phaeoisariopsis griseola occurring in Kenya

The wide pathogenic variability occurring in Phaeoisariopsis griseola , the causal agent of angular leaf spot of common bean ( Phaseolus vulgaris L.), dictates that new sources of resistance be continuously identified. This study was undertaken to determine the reaction of selected bean genotypes to different races of P. griseola in order to identify potential sources of resistance to angular leaf spot. Selected bean genotypes from Eastern and Central Africa Bean Research Network (ECABREN) and National Dryland Farming Research Centre (NDFRC), Katumani in Kenya were separately inoculated with forty-four races of P. griseola and evaluated for disease development under greenhouse conditions. The genotypes included small- and large-seeded types. None of the genotypes was resistant to all the races, indicating a high complexity of the pathogen population. Thirteen genotypes were resistant (disease score 1 to 3) or moderately resistant (score 4 to 6) to at least 40 of the races. Small-seeded bean genotypes ECAB 0754 and ECAB 0617 were resistant or moderately resistant to all races except Mesoamerican race 33-39 and Afro-Andean race 58-18, respectively. Genotype ECAB 0754 exhibited the highest level of resistance, with an average disease severity of 1.1%. All the resistant or moderately resistant genotypes were of the small-seeded bean types which are commercially less popular. The commonly grown large-seeded genotypes were generally susceptible. Among the bean genotypes evaluated, the small-seeded pintos and browns/yellows possessed high levels of resistance. The results of this study indicate that different bean genotypes have varying levels of resistance to angular leaf spot that can be pyramided into appropriate background to provide durable resistance.Une large variabilité pathogénique du Phaeoisariopsis griseola , l’agent causal de la tâche angulaire de feuilles du haricot commun ( Phaseolus vulgaris L.), suggère qu’il y’ait une identification continue de nouvelles sources de résistance. Cette étude était entreprise pour déterminer la réaction des génotypes de haricot sélectionnés aux différentes races de P. griseola afin d’identifier de sources potentielles de résistance à la maladie de tâche angulaire de la feuille. Les génotypes de haricot fournis par l’Eastern and Central Africa Bean Research Network (ECABREN) et le National Dryland Farming Research Centre (NDFRC), Katumani au Kenya étaient séparément inoculés avec quarante-quatre races de P. griseola pour l’évaluation en serre du développement de maladies. Les génotypes comprenaient de petits et gros grains de semences. Aucune des génotypes n’était résistant à toutes les races de maladies, indicant ainsi une complexité élevée de la population des pathogènes. Treize génotypes étaient résistants (échelle de cotation: 1 à 3) ou modérément résistants (échelle de cotation: 4 à 6) sur au moins quarante de toutes les races. Les génotypes de haricot à petits grains ECAB 0754 et ECAB 0617 étaient résistants ou modérément résistants à toutes les races à l’exception de Mesoamerican race 33-39 et Afro-Andean race 58-18, respectivement. Le Génotype ECAB 0754 avait manifesté un niveau élevé de résistance, avec un taux moyen de séverité de 1.1%. Tous les génotypes résistants ou modérément résistants étaient de ceux à petits grains commercialement moins populaires. Les génotypes à gros grains communément cultivés étaient généralement susceptibles. Parmi les génotypes évalués, ceux à petits grains "pintos" et bruns/jaunes étaient dotés des niveaux élevés de résistance. Les résultats de cette étude montrent que différents génotypes de haricot possèdent de niveaux différents de résistance à la maladie de tâche angulaire de la feuille pouvant être combinés par pyramidage pour développer une variété de haricot à résistance durable

Women’s vulnerability in bean value chain development at the Maendeleo innovation platform, Eastern DRC

Value chain development in post conflict countries should not only deal with the technical issues of the value chain, but with women’s gender needs, and even more critically understand and address their vulnerabilities. The aim of this study was to investigate the vulnerabilities of women involved in a bean value chain development intervention at the Maendeloe Innovation Platform in Eastern DRC. Specifically, the paper first discusses the roles of women and men in the value chain, what production resources and benefits they access and control, the role of the IP as a vehicle for women’s empowerment, and identifies women’s gender needs. Secondly, the paper identifies women’s vulnerabilities, and the capacities that the IP could build on, to support their participation in bean value chain development. Using gender analysis tools, the study shows that in addition to the lack of control of productive resources, household assets and the benefits of their labour, women have been traumatized by the rampant sexual violation and gender-based violence in the region. The innovation platform should consider including legal, mental health and psychosocial counselling service providers as stakeholders in its activities to develop the bean value chain

Women’s vulnerability in bean value chain development at the Maendeleo innovation platform, Eastern DRC

Value chain development in post conflict countries should not only deal with the technical issues of the value chain, but with women’s gender needs, and even more critically understand and address their vulnerabilities. The aim of this study was to investigate the vulnerabilities of women involved in a bean value chain development intervention at the Maendeloe Innovation Platform in Eastern DRC. Specifically, the paper first discusses the roles of women and men in the value chain, what production resources and benefits they access and control, the role of the IP as a vehicle for women’s empowerment, and identifies women’s gender needs. Secondly, the paper identifies women’s vulnerabilities, and the capacities that the IP could build on, to support their participation in bean value chain development. Using gender analysis tools, the study shows that in addition to the lack of control of productive resources, household assets and the benefits of their labour, women have been traumatized by the rampant sexual violation and gender-based violence in the region. The innovation platform should consider including legal, mental health and psychosocial counselling service providers as stakeholders in its activities to develop the bean value chain