Consultative Group on International Agricultural Research
Recent publications
High‐throughput sequencing (HTS) is a powerful tool that enables the simultaneous detection and potential identification of any organisms present in a sample. The growing interest in the application of HTS technologies for routine diagnostics in plant health laboratories is triggering the development of guidelines on how to prepare laboratories for performing HTS testing. This paper describes general and technical recommendations to guide laboratories through the complex process of preparing a laboratory for HTS tests within existing quality assurance systems. From nucleic acid extractions to data analysis and interpretation, all of the steps are covered to ensure reliable and reproducible results. These guidelines are relevant for the detection and identification of any plant pest (e.g. arthropods, bacteria, fungi, nematodes, invasive plants or weeds, protozoa, viroids, viruses), and from any type of matrix (e.g. pure microbial culture, plant tissue, soil, water), regardless of the HTS technology (e.g. amplicon sequencing, shotgun sequencing) and of the application (e.g. surveillance programme, phytosanitary certification, quarantine, import control). These guidelines are written in general terms to facilitate the adoption of HTS technologies in plant pest routine diagnostics and enable broader application in all plant health fields, including research. A glossary of relevant terms is provided among the Supplementary Material. Le séquençage haut débit (HTS) est un outil puissant qui permet, simultanément, la détection et l'identification potentielle de tout organisme présent dans un échantillon. L'application des technologies HTS suscite un intérêt croissant dans les laboratoires phytosanitaires pour les activités de diagnostic de routine et cet intérêt a conduit à l'élaboration de directives sur la manière de préparer les laboratoires à effectuer des tests HTS. Cet article décrit les recommandations générales et techniques, élaborées afin de guider les laboratoires dans le processus complexe de se préparer aux tests HTS, dans le cadre des systèmes d'assurance qualité existants. De l'extraction des acides nucléiques à l'analyse et interprétation des données, toutes les étapes sont décrites afin de garantir des résultats fiables et reproductibles. Ces directives sont applicables pour la détection et l'identification de tout organisme nuisible aux végétaux (p. ex. arthropodes, bactéries, champignons, nématodes, plantes ou adventices envahissantes, protozoaires, viroïdes, virus), et à partir de tout type de matrice (culture microbienne pure, tissu végétal, sol, eau), quelle que soit la technologie HTS (p. ex. séquençage d’amplicons, séquençage shotgun) et l'application (p. ex. programme de surveillance, certification phytosanitaire, quarantaine, contrôle des importations). Ces directives sont rédigées avec des termes génériques afin de faciliter l'adoption des technologies HTS dans les activités de diagnostic phytosanitaire de routine et de permettre une application plus large dans tous les domaines de la santé des végétaux, y compris le domaine de la recherche. Un glossaire des termes utiles est fourni dans les documents complémentaires. Высокопроизводительное секвенирование (HTS) ‐ это мощный инструмент, позволяющий одновременно обнаруживать и потенциально идентифицировать любые организмы, присутствующие в образце. Растущий интерес к применению технологий HTS для рутинной диагностики в лабораториях, занимающихся здоровьем растений, требует разработку рекомендаций по подготовке лабораторий к проведению HTS‐тестирования. В данном документе описаны общие и технические рекомендации, которые помогут лабораториям пройти сложный процесс подготовки лаборатории к проведению HTS‐тестов в рамках существующих систем обеспечения качества. Рассматриваются все этапы для обеспечения надежных и воспроизводимых результатов, начиная с выделения нуклеиновых кислот и заканчивая анализом и интерпретацией данных. Настоящее руководство актуально для обнаружения и идентификации любого вредного организма растений (например, членистоногих, бактерий, грибов, нематод, инвазивных растений или сорняков, простейших, вироидов, вирусов) и из любого типа матрицы (например, чистая культура микроорганизмов, ткани растений, почва, вода), независимо от технологии ВПC (например, ампликонное секвенирование, дробовое секвенирование) и области применения (например, программа надзора, фитосанитарная сертификация, карантин, контроль импорта). Настоящее руководство составлено в общих терминах, чтобы облегчить внедрение технологий HTS в рутинную диагностику вредителей растений и обеспечить её более широкое применение во всех областях защиты растений, включая научные исследования. В дополнительных материалах приводится глоссарий соответствующих терминов.
Women are at a particular disadvantage by the stress that climate change poses on food systems in low- and middle-income countries (LMICs) as their adaptive capacity is hampered by unequal access to resources and services and constraints to their agency. This paper proposes a methodology to identify climate–agriculture–gender inequality hotspot LMICs and subnational areas where climate hazards converge with large concentrations of women participating in food systems and social conditions that disadvantage women. The methodology applies data reduction techniques on publicly available data to compute a hotspot index that forms the basis for ranking and mapping hotspots. Applying the methodology illustrates the hottest of 87 LMICs are located in Africa and identifies crop-specific hotspot subnational areas in four focus countries. Identifying hotspots can enable targeting populations at highest risk and render future efforts to support women’s agency for climate resilience and avert increasing gender inequalities more effective.
The African "youth" population is growing at a fast and steady pace, attracting attention from scholars, policymakers, and politicians. Yet, we know relatively little about this large and heterogeneous segment of the population. This paper presents data from 110 interviews and ten focus groups with youth engaged in commercial agriculture across all four regions of Uganda. Capitalising on this ethnographic data, we provide an analytical framework for studying complexity among the heterogeneous social category of youth agripreneurs. The aim of the paper is twofold: First, to reconcile anthropological studies that highlight the heterogeneity of African youth with demographic understandings of youth as a statistical category defined by an age bracket. Second, to advance an operational definition of youth that allows for more context-sensitive and tailored programmes. Our results suggest that while "youth" is an important category demographically, the opportunities and challenges faced by youths are often not related to age.
Potato late blight (LB), caused by the oomycete, Phytophthora infestans, continues to be a major constraint of potato in the Andean region and worldwide. Farmers perception regarding potato production with particular emphasis on management practices for LB was surveyed in two communities in the Peruvian highlands using a questionnaire with 25 questions, many with multiple choice questions. In the village of Paucartambo, 84 women and 485 men of different ages participated in the survey, while in the village of Ulcumayo, there were 146 women and 396 men, also of different ages. Overall, responses were similar between the two locations, with some small but significant differences. In general, there was a very clear association between age and education, with only young men and women having secondary education. Respondents in both locations overwhelmingly chose LB as the main constraint to production and cited either personal experience or agrochemical vendors as the primary sources of information about disease management. Many cultivars (25+) are grown in both locations, with the two most important cultivars, Yungay and Huayro, being common in both locations while others differed. There was evidence of confusion around the concept of host plant resistance, as certain cultivars were cited as both relatively resistant and susceptible. Many trade names of fungicides were recalled by respondents, but most were relatively old products. Correspondence analysis indicated gender effects on LB management practices and information sources in both locations that could be taken into consideration to refine future interventions for research and capacity building, such as offering refresher training courses for extension educators, including female extension workers, to help farmers understand basic concepts to manage host resistance and fungicides properly, and improve access to resistant varieties and effective fungicides.
The Moderate Resolution Imaging Spectroradiometer Vegetation Continuous Fields (MODIS VCF) Earth observation product is widely used to estimate forest cover changes and to parameterize vegetation and Earth system models and as a reference for validation or calibration where field data are limited. However, although limited independent validations of MODIS VCF have shown that MODIS VCF's accuracy decreases when estimating tree cover in sparsely vegetated areas such as tropical savannas, no study has yet assessed the impact this may have on the VCF-based tree cover data used by many in their research. Using tropical forest and savanna inventory data collected by the Tropical Biomes in Transition (TROBIT) project, we produce a series of calibration scenarios that take into account (i) the spatial disparity between the in situ plot size and the MODIS VCF pixel and (ii) the trees' spatial distribution within in situ plots. To identify if a disparity also exists in products trained using VCF, we used a similar approach to evaluate the finer-scale Landsat Tree Canopy Cover (TCC) product. For MODIS VCF, we then applied our calibrations to areas identified as forest or savanna in the International Geosphere-Biosphere Programme (IGBP) land cover mapping product. All IGBP classes identified as “savanna” show substantial increases in cover after calibration, indicating that the most recent version of MODIS VCF consistently underestimates woody cover in tropical savannas. We also found that these biases are propagated in the finer-scale Landsat TCC. Our scenarios suggest that MODIS VCF accuracy can vary substantially, with tree cover underestimation ranging from 0 % to 29 %. Models that use MODIS VCF as their benchmark could therefore be underestimating the carbon uptake in forest–savanna areas and misrepresenting forest–savanna dynamics. Because of the limited in situ plot number, our results are designed to be used as an indicator of where the product is potentially more or less reliable. Until more in situ data are available to produce more accurate calibrations, we recommend caution when using uncalibrated MODIS VCF data in tropical savannas.
Con el objetivo de identificar las especies de Phytophthora asociadas a la mazorca negra y al cáncer del tallo del cacao en Antioquia, Colombia, se realizó la caracterización e identificación morfológica y molecular de 120 aislados de Phytophthora spp. obtenidos de mazorcas, tallos y muestras de suelo en 11 municipios de este departamento. Se evaluaron caracteres morfológicos en esporangios y clamidosporas, la formación de estructuras sexuales, el patrón y la tasa de crecimiento de las colonias y las temperaturas cardinales. La identificación molecular se llevó a cabo mediante PCR convencional con cebadores género-específicos y qPCR. Los 120 obtenidos se identificaron como Phytophthora, 119 como P. palmivora y la cepa CH6-3S no coincidió con ninguna especie de Phytophthora previamente reportada como patógena de cacao. Un modelo de escalamiento multidimensional basado en atributos morfológicos mostró una amplia diversidad en el tamaño y forma de los esporangios (ocho morfotipos); sin embargo, la variabilidad de los aislados fue baja (17 %) y los subgrupos formados no mostraron relación con las localidades, ni con el tipo de tejido de donde se obtuvieron.
With a global market of 30 billion USD, agricultural insurance plays a key role in risk finance and contributes to climate change adaptation by achieving Sustainable Development Goals (SDGs) including no poverty, zero hunger, and climate action. The existing evidence in agricultural insurance is scattered across regions, topics and risks, and a structured synthesis is unavailable. To address this gap, we conducted a systematic review of 796 peer-reviewed papers on agricultural insurance published between 2000 and 2019. The goal of this review was twofold: 1) categorizing agricultural insurance literature by agricultural product insured, research theme, geographical study area, insurance type and hazards covered, and 2) mapping country-wise research intensity of these indicators vis-à-vis historical and projected risk and crisis events—extreme weather disasters, projected temperature increase under SSP5 (Shared Socioeconomic Pathways) scenario and livestock epidemics. We find that insurance research is focused on high-income countries while crops are the dominating agricultural product insured (33% of the papers). Large producers in production systems like fruits and vegetables (South America), millets (Africa) and fisheries and aquaculture (South-east Asia) are not focused upon in the literature. Research on crop insurance is taking place where historical extreme weather disasters are frequent (correlation coefficient of 0.75), while we find a surprisingly low correlation between climate change induced temperature increases in the future and current research on crop insurance, even when sub-setting for papers on the research theme of climate change and insurance (-.04). There is also limited evidence on the role of insurance to scale adaptation and mitigation measures to de-risk farming. Further, we find that the study area of livestock insurance papers is weakly correlated to the occurrence of livestock epidemics in the past (-.06) and highly correlated to the historical drought frequency (.51). For insurance to play its relevant role in climate change adaptation as described in the Sustainable Development Goals (SDGs), we recommend governments, insurance companies and researchers to better tune their interest to risk-prone areas and include novel developments in agriculture which will require major investments, and, hence, insurability, in the coming years.
This paper examines the question of what makes choice empowering and critiques prevalent approaches to empowerment focused narrowly on agency as the ability of individuals to make their own free choices and act independently. The implications of a narrow focus on agency are illustrated with the examples of technology choice in agriculture, specifically choices involved in the adoption of improved plant varieties. This example elucidates the limits of individual agency and permits an analysis of how choices may be structured to be either empowering or disempowering, with examples from specific plant breeding cases. In view of the importance given to equitable choice of technology for closing the gender gap in agricultural productivity and sustainability, the paper explores what practical steps can be taken towards a balanced approach to empowerment. An approach to designing a new plant variety by constructing choice differently is illustrated, using information on gender relations. The paper derives lessons from the plant breeding cases to inform other kinds of interventions, so that work on how choices are defined is given as much importance for empowerment as creating the option to choose. Agents who exercise power over rules and resources can either reproduce the status quo or innovate; thus, a balanced approach to empowerment requires careful analysis of the elements of choice.
This paper proposes scenarios to achieve more crop per drop and irrigation for all in water-scarce irrigation systems, with a particular reference to India. It uses economic water productivity (EWP) and water cost curve for EWP as tools to reallocate irrigation consumptive water use (CWU) and identify economically viable cropping patterns. Assessed in the water-scarce Sina irrigation system in Maharashtra, India, the method shows that drought-tolerant annual crops such as fruits and/or fodder should be the preferred option in irrigated cropping patterns. Cropping patterns with orchard or fodder as permanent fixtures will provide sustainable income in low rainfall years. Orchards in combination with other crops will increase EWP and value of output in moderate to good rainfall years. Governments should create an enabling environment for conjunctive water use and allocation of CWU to achieve a gradual shift to high-value annual/perennial crops as permanent fixtures in cropping patterns. Highlights Economic water productivity is a critical performance indicator when water has an opportunity cost.; Water cost curve assesses the financial trade-off of different cropping patterns.; Adapting to weather variability is imperative for water-scarce irrigation systems.; Drought-tolerant annual crops should be a permanent feature in cropping patterns.; Enabling a policy environment for conjunctive water use is necessary for change.;
Banana mild mosaic virus (BanMMV) (Betaflexiviridae, Quinvirinae, unassigned species) is a filamentous virus belonging to the Betaflexiviridae family. It infects Musa spp. with a very wide geographic distribution. The genome variability of plant viruses, including the members of the Betaflexiviridae family, makes their molecular detection by specific primers particularly challenging. During routine indexing of the Musa germplasm accessions, a discrepancy was observed between electron microscopy and immunocapture (IC) reverse transcription (RT) polymerase chain reaction (PCR) test results for one asymptomatic accession. Filamentous viral particles were observed while molecular tests failed to amplify any fragment. The accession underwent high-throughput sequencing and two complete genomes of BanMMV with 75.3% of identity were assembled. Based on these sequences and on the 54 coat protein sequences available from GenBank, a new forward primer, named BanMMV CP9, compatible with Poty1, an oligodT reverse primer already used in diagnostics, was designed. A retrospective analysis of 110 different germplasm accessions from diverse origins was conducted, comparing BanMMCP2 and BanMMV CP9 primers. Of these 110 accessions, 16 tested positive with both BanMMCP2 and BanMMV CP9, 3 were positive with only BanMMCP2 and 2 tested positive with only BanMMV CP9. Otherwise, 89 were negative with the two primers and free of flexuous virions. Sanger sequencing was performed from purified PCR products in order to confirm the amplification of the BanMMV sequence for the five accessions with contrasting results. It is highly recommended to use the two primers successively to improve the inclusiveness of the protocol.
A severe El Niño event in 2015/16 decimated an important share of Papua New Guinea's (PNG) local crop production, leaving 10 per cent of the population with significant food shortages. Lack of recent socio‐economic data and analysis of the country's rural population impeded efforts to plan and mitigate the ensuing food crisis. This paper presents the most recent poverty analysis in Papua New Guinea in nearly a decade, and a renewed effort to inform rural production, consumption and livelihood patterns in some of the country's most remote, lowland areas. We designed a rural household survey that collected detailed consumption and expenditure data to explore poverty prevalence and correlates of per capita household expenditure. Results suggest that approximately half of the sampled individuals live in households with total per capita expenditures below the poverty line. Climate shocks have significant and possibly long‐term consequences for household welfare. Households that experienced a drought in the last 5 years are associated with significantly lower per capita expenditures. Labour diversification, via migration, is associated with greater welfare. Households with at least one migrant member are associated with 13 per cent greater per capita expenditure.
Three species of potato tuber moths, Tecia solanivora Povolny, Symmetrischema tangolias Gyen, and Phthorimaea operculella Zeller (all Lepidoptera: Gelechiidae), attack potato plants in the highlands of Ecuador and cause great economic losses. To understand their ecology and to develop precise integrated pest management strategies, a description of the molecular identification of each species and genetic diversity within populations is needed. In this study, we assessed the genetic diversity of a total of 112 moth samples of these 3 distinct species. Samples were collected from the 4 central provinces (Bolvar, Chimborazo, Cotopaxi, and Tungurahua) in the Ecuadorian highlands, where potato is a major crop for food security. Using polymerase chain reaction (PCR) and Sanger sequencing, we compared mitochondrial gene sequences among conspecific moth samples. Each of the 3 species exhibited different patterns regarding genetic diversity; more than 1 haplotype was present in P. operculella and S. tangolias, whereas all T. solanivora samples were found to be genetically identical. This initial effort of molecular characterization of the potato tuber moths will facilitate identifying incursion and potential migration route of Gelechiidae species as well as prevention of the pest outbreaks.
A large portion of sub-Saharan Africa is situated in belts of uncertain rainfall and are characterized by low soil fertility with limited capacity to adapt to and mitigate the impacts of climate change. A field study was conducted in the semi-humid potato-growing belt of Kenya to test the effect of legume intercropping and water soluble silicon (orthocilicic acid) on soil erosion, and use efficiency of light and water. Potato (Solanum tuberosum L.) was grown singly and intercropped with dolichos (Lablab purpureus L.) or hairy vetch (Vicia sativa L.). Each cropping system was subjected to granular water-soluble silicon (Si) amendment at two rates (2.5 kg Si ha-1 (+Si) vs 0 kg Si ha-1 (-Si)). Plants receiving Si maintained significantly higher (p < 0.05) percent relative leaf water content (62–89% vs 52–72% in controls) and exhibited higher concentrations of proline (1.99–2.91 vs 1–1.19 մmol g-1), soluble carbohydrates (28–59 vs 10–28 մmol g-1) and electrolyte conductance (1409–3903 vs 746–2307 mS cm-1). Legume intercropping enhanced groundcover establishment and reduced soil and nutrient losses by 45–80% compared with sole potato. Crop yields were 2–3 fold greater in intercropping relative to sole potato and were significantly greater in treatments subjected to Si application. Land equivalent ratios were above unity in intercropping but less than unity in sole potato, and were 8–20% increased by Si application. Use efficiency of water (5.99–9.09 Kg ha-1 m-3) and light (1.98–2.98 g MJ-1) were significantly greater under legume intercropping compared with sole potato (1.13–3.23 Kg ha-1 m-3 and 0.77–0.98 g MJ-1 respectively) and increased with Si application. Integrative use of Si and legume intercropping presents the smallholder farmers an opportunity to increase productivity of potato while enhancing resource use efficiency and soil fertility in the semi-humid tropics.
En este trabajo se desarrolla una propuesta para comparar diferentes metodologías de optimización multirespuesta aplicadas a superficies de respuesta (RSM) en diseños experimentales, como herramientas de solución a problemas presentes principalmente en el área industrial. Se estudian las siguientes metodologías: función de deseabilidad (DES), MOORA (MOO), TOPSIS (TOP), MULTIMOORA (MMO), MOORA AD (MAD), TOPSIS AD (TAD) y redes neuronales multicapa (con los paquetes Neuralnet (NEU) y Nnet (NET)). Cada una de estas técnicas se aplican a tres casos de interés comercial o industrial con diferentes diseños experimentales (Taguchi, Box-Behnken y Diseño Central Compuesto), en un estudio de simulación Monte Carlo donde se considera como factores las diferentes técnicas comparadas, el tipo de diseño experimental y diferentes escenarios de correlaciones. Se comparan las técnicas por medio de una métrica que evalúa la distancia de cada respuesta estimada respecto a su valor ideal o deseado, con el fin de analizar las ventajas y desventajas de cada método. Los resultados obtenidos son consistentes en cada uno de los casos abordados y se concluye que las redes neuronales Neuralnet (NEU) son el mejor método, en segundo lugar, la función de deseabilidad (DES) y las redes neuronales Nnet (NET). Además, se encontró que el método MOORA AD (MAD) propuesto, tiene un excelente desempeño en un caso de estudio particular. Se recomienda en estudios comparativos futuros, emplear más tipos de diseños experimentales y aplicar más técnicas de optimización multirespuesta disponibles, con el fin de obtener mayor información sobre los escenarios y condiciones que muestren mejor desempeño y realizar sugerencias de implementación más puntuales. Todo el desarrollo se realizó en R (R Core Team, 2019) con el fin de promover el uso de software libre con fines de investigación o desarrollo comercial.
En el proceso de mejoramiento genético de trigo, la evaluación de genotipos por resistencia a royas es fundamental, se tienen que mezclar distintas razas; sin embargo, es primordial conocer su habilidad competitiva y en que genotipo se deben incrementar; por lo que el objetivo del estudio fue medir la habilidad competitiva de cuatro razas de roya de la hoja causada por Puccinia triticina E. que atacan trigos cristalinos (Triticum durum). El estudio se realizó en invernadero durante el año 2015. Las razas BBG/BN, BCG/BN, BBG/BP y CBG/BP, fueron mezcladas y multiplicadas por tres generaciones sucesivas en genotipos susceptibles (Atil C2001 y Morocco), genotipos resistentes (Samayoa C2004 y Thatcher-Lr16 (RL6005)) además de Júpare C2001 resistente a BBG/BN y BCG/BN, pero susceptible a BBG/BP y CBG/BP. Después de la reproducción de urediniosporas, se obtuvieron 100 aislamientos que se incrementaron en Morocco y se procedió a la identificación. La raza identificada con más frecuencia fue CBG/BP con 46%, seguida de BBG/BP con 34% y BBG/BN con 18%, mientras que BCG/BN fue la menos frecuente con 2%. Solo en urediniosporas del compuesto masal (CM) obtenidos de RL6005 y Morocco permitió identificar las cuatro razas, en Atil C2001, Júpare C2001 y Samayoa C2004 solo se identificaron tres. La raza identificada con más frecuencia en Atil C2001, RL6005 y Samayoa C2004 fue BBG/BP, mientras que en Morocco y Júpare C2001, fue CBG/BP. Se concluye que CBG/BP es más competitiva que BBG/BP, BBG/BN y BCG/BN y se recomienda usarse en la mezcla.
Monitoring and assessment of vegetation phenology at the regional to global scale are essential to understand the characteristics of various biophysical parameters in terrestrial ecosystems. Passive optical remote sensing data have been used extensively in the recent past to study phenology of vegetation, also called land surface phenology, at diverse landscapes across the globe. In the present study, the moderate resolution imaging spectroradiometer (MODIS)-derived enhanced vegetation index (EVI) time series data (2000–2013) was used to study the phenology of dry and moist teak (Tectona grandis) forests of different biogeographic provinces of India. Four phenology metrics, viz., start of season (SOS), end of season (EOS), peak of season (POS) and length of season (LOS) were derived using the TIMESAT tool. The SOSs’ of dry and moist teak were found during July–August. LOS of moist teak was found to be much longer (~ 48 days) than dry teak. Also, a significant difference of leaf area index (LAI) (~ 2.8) of dry and moist teak forests was noticed during peak season from MODIS LAI product (MOD15A2). Vegetation phenology is greatly responsive to the fluctuation of climatic parameters such as rainfall. Hence, pre-season cumulative rainfall data were analysed to understand the control of rainfall over phenological variations in natural teak forests of India. It was noticed that rainfall was reasonably well correlated with SOS (R² = 0.57–0.72) for both types of teak forests. The study highlighted the efficacy of time series MODIS EVI data to study the phenological variations in different teak forest types of India in a data-limited situation.
Introducción. La Altillanura colombiana atraviesa por un proceso de transformación, marcado por la expansión de su frontera agrícola. En la región, se está implementando una agenda de investigación que busca desarrollar y validar tecnologías promisorias para el mejoramiento de la productividad y la sostenibilidad de los sistemas de producción agropecuarios. La evaluación económica juega un papel importante en priorizar actividades, asignar recursos y guiar la investigación agrícola hacia objetivos de desarrollo rural. Objetivo. El objetivo de este trabajo fue implementar una evaluación económica ex-ante para estimar los resultados e impactos potenciales de la nueva línea promisoria de arroz L23 desarrollada para la Altillanura colombiana. Materiales y métodos. El impacto se midió en el genotipo de arroz L23, desarrollado en colaboración por la Corporación Colombiana de Investigación Agropecuaria (AGROSAVIA) y el Centro Internacional de Agricultura Tropical (CIAT), para la Altillanura colombiana. La evaluación ex-ante efectuada combinó un análisis de presupuestos parciales con información de pruebas experimentales y un modelo de excedentes económicos. Resultados. Los dos enfoques metodológicos fueron consistentes y mostraron que con la adopción del genotipo L23, en al menos 29,7 %, se podría conseguir una rentabilidad del 17,1 % para los productores de arroz de la Altillanura, debido al aumento esperado del rendimiento en el cultivo. Sin embargo, un análisis de sensibilidad de los supuestos, alerta que un bajo nivel potencial de adopción junto a cambios no significativos en rendimiento convertiría la investigación y desarrollo del nuevo genotipo en no factible a nivel económico. Conclusión. Para que la investigación, desarrollo e introducción del genotipo de arroz L23 sea rentable, se requiere un proceso de diseminación que permita la reproducción de la semilla y facilite el acceso a los productores, para que así puedan alcanzar mayores niveles de adopción.
This paper contributes to the existing literature on rainfall variability and food security. It analyses the effect of rainfall variability on food security for 71 developing countries from 1960 to 2016. Results suggest that rainfall variability reduces food security in developing countries. Indeed it reduces food availability per capita and increases the percentage of total undernourished population. Moreover, the negative effects of rainfall variability are exacerbated in the presence of civil conflicts and are high for the countries that are vulnerable to food price shocks.
Bacterial wilt (BW) caused by the Ralstonia solanacearum species complex (RSSC) is a serious threat to potato production in Uganda. However, little is known about the extent of the disease and the type of the pathogen strains involved. A nationwide survey was conducted to study BW prevalence and incidence in potato, and potato tuber and stem samples of potential alternative hosts were collected for pathogen isolation. DNA was extracted from pure cultures for genetic diversity studies. The pathogen was phylotyped by multiplex PCR; then, a subset of isolates was typed at sequevar level. Isolates of the same sequevar were then haplotyped using multilocus tandem repeat sequence typing (TRST) schemes. BW prevalence and incidence in potato farms were 81.4 and 1.7%, respectively. Three RSSC phylotypes were identified, with the majority of the strains belonging to Phylotype II (80%) followed by Phylotype I (18.5%) and III (1.5%). Phylotype I strains belonged to Sequevar 31, and Phylotype II strains belonged to Sequevar 1. Potato-associated Phylotype II Sequevar 1 strains were more diverse (27 TRST haplotypes) than nonpotato Phylotype I (5 TRST haplotypes). Mapping of TRST haplotypes revealed that three TRST haplotypes of Phylotype II Sequevar 1 strains play an important epidemiological role in BW of potato in Uganda being disseminated via latently infected seed. [Formula: see text] Copyright © 2019 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .
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Mahalingam Govindaraj
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Mabrouk A. El-Sharkawy
  • International Center for Tropical Agriculture (CIAT)
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