Showing papers by "International Potato Center published in 2011"

Genome sequence and analysis of the tuber crop potato.

Abstract: Potato (Solanum tuberosum L.) is the world's most important non-grain food crop and is central to global food security. It is clonally propagated, highly heterozygous, autotetraploid, and suffers acute inbreeding depression. Here we use a homozygous doubled-monoploid potato clone to sequence and assemble 86% of the 844-megabase genome. We predict 39,031 protein-coding genes and present evidence for at least two genome duplication events indicative of a palaeopolyploid origin. As the first genome sequence of an asterid, the potato genome reveals 2,642 genes specific to this large angiosperm clade. We also sequenced a heterozygous diploid clone and show that gene presence/absence variants and other potentially deleterious mutations occur frequently and are a likely cause of inbreeding depression. Gene family expansion, tissue-specific expression and recruitment of genes to new pathways contributed to the evolution of tuber development. The potato genome sequence provides a platform for genetic improvement of this vital crop.

BioMart Central Portal: an open database network for the biological community

Abstract: BioMart Central Portal is a first of its kind, community-driven effort to provide unified access to dozens of biological databases spanning genomics, proteomics, model organisms, cancer data, ontology information and more. Anybody can contribute an independently maintained resource to the Central Portal, allowing it to be exposed to and shared with the research community, and linking it with the other resources in the portal. Users can take advantage of the common interface to quickly utilize different sources without learning a new system for each. The system also simplifies cross-database searches that might otherwise require several complicated steps. Several integrated tools streamline common tasks, such as converting between ID formats and retrieving sequences. The combination of a wide variety of databases, an easy-to-use interface, robust programmatic access and the array of tools make Central Portal a one-stop shop for biological data querying. Here, we describe the structure of Central Portal and show example queries to demonstrate its capabilities.

Complexity in climate-change impacts: an analytical framework for effects mediated by plant disease

Abstract: The impacts of climate change on ecosystem services are complex in the sense that effective prediction requires consideration of a wide range of factors. Useful analysis of climate-change impacts on crops and native plant systems will often require consideration of the wide array of other biota that interact with plants, including plant diseases, animal herbivores, and weeds. We present a framework for analysis of complexity in climate-change effects mediated by plant disease. This framework can support evaluation of the level of model complexity likely to be required for analysing climate-change impacts mediated by disease. Our analysis incorporates consideration of the following set of questions for a particular host, pathogen, host–pathogen combination, or geographic region. 1. Are multiple biological interactions important? 2. Are there environmental thresholds for population responses? 3. Are there indirect effects of global change factors on disease development? 4. Are spatial components of epidemic processes affected by climate? 5. Are there feedback loops for management? 6. Are networks for intervention technologies slower than epidemic networks? 7. Are there effects of plant disease on multiple ecosystem services? 8. Are there feedback loops from plant disease to climate change? Evaluation of these questions will help in gauging system complexity, as illustrated for fusarium head blight and potato late blight. In practice, it may be necessary to expand models to include more components, identify those components that are the most important, and synthesize such models to include the optimal level of complexity for planning and research prioritization.

RNAi-mediated resistance to diverse isolates belonging to two virus species involved in Cassava brown streak disease

Abstract: Cassava brown streak disease (CBSD) is emerging as one of the most important viral diseases of cassava (Manihot esculenta) and is considered today as the biggest threat to cassava cultivation in East Africa. The disease is caused by isolates of at least two phylogenetically distinct species of single-stranded RNA viruses belonging to the family Potyviridae, genus Ipomovirus. The two species are present predominantly in the coastal lowland [Cassava brown streak virus (CBSV); Tanzania and Mozambique] and highland [Cassava brown streak Uganda virus (CBSUV); Lake Victoria Basin, Uganda, Kenya and Malawi] in East Africa. In this study, we demonstrate that CBSD can be efficiently controlled using RNA interference (RNAi). Three RNAi constructs targeting the highland species were generated, consisting of the full-length (FL; 894 nucleotides), 397-nucleotide N-terminal and 491-nucleotide C-terminal portions of the coat protein (CP) gene of a Ugandan isolate of CBSUV (CBSUV-[UG:Nam:04]), and expressed constitutively in Nicotiana benthamiana. After challenge with CBSUV-[UG:Nam:04], plants homozygous for FL-CP showed the highest resistance, followed by the N-terminal and C-terminal lines with similar resistance. In the case of FL, approximately 85% of the transgenic plant lines produced were completely resistant. Some transgenic lines were also challenged with six distinct isolates representing both species: CBSV and CBSUV. In addition to nearly complete resistance to the homologous virus, two FL plant lines showed 100% resistance and two C-terminal lines expressed 50–100% resistance, whereas the N-terminal lines succumbed to the nonhomologous CBSV isolates. Northern blotting revealed a positive correlation between the level of transgene-specific small interfering RNAs detected in transgenic plants and the level of virus resistance. This is the first demonstration of RNAi-mediated resistance to CBSD and protection across very distant isolates (more than 25% in nucleotide sequence) belonging to two different species: Cassava brown streak virus and Cassava brown streak Uganda virus.

Identification of quantitative trait loci for dry-matter, starch, and β-carotene content in sweetpotato

Abstract: Development of orange-fleshed sweetpotatoes (OFSP) is desired for the improvement of the food supply and nutritional status of millions of people in developing countries, particularly in sub-Saharan Africa. However, sweetpotato [Ipomoea batatas (L.) Lam] breeding is challenging due to its genetic complexity, and marker-assisted breeding tools are needed to facilitate crop improvement. We identified quantitative trait loci (QTL) for dry-matter, starch, and β-carotene content in a hexaploid sweetpotato mapping population derived from a cross between Tanzania, a white-fleshed, high dry-matter African landrace, and Beauregard, an orange-fleshed, low dry-matter sweetpotato cultivar popular in the USA. Two parental maps were constructed using a population of 240 clones. Strong correlations were observed between starch and dry-matter content (r > 0.8, P < 0.0001) in the storage roots, while moderate correlations (r = –0.6, P < 0.0001) were observed for β-carotene and starch content. In both parental maps, QTL analysis revealed the presence of 13 QTL for storage root dry-matter content, 12 QTL for starch content, and 8 QTL for β-carotene content. Multiple QTL regression models developed for segregation of alleles in each parent explained 15–24% of the variation in dry-matter content, 17–30% of the starch content, and 17–35% of β-carotene content. To the best of our knowledge, this research presents the only QTL mapping study published to date for dry-matter, starch, and β-carotene content in sweetpotato. This work improves our understanding of the inheritance of these important traits in sweetpotato, and represents a first step toward the long-term goal of developing marker-assisted breeding tools to facilitate sweetpotato breeding efforts.

The Plant Pathogen Phytophthora andina Emerged via Hybridization of an Unknown Phytophthora Species and the Irish Potato Famine Pathogen, P. infestans

Abstract: Emerging plant pathogens have largely been a consequence of the movement of pathogens to new geographic regions. Another documented mechanism for the emergence of plant pathogens is hybridization between individuals of different species or subspecies, which may allow rapid evolution and adaptation to new hosts or environments. Hybrid plant pathogens have traditionally been difficult to detect or confirm, but the increasing ease of cloning and sequencing PCR products now makes the identification of species that consistently have genes or alleles with phylogenetically divergent origins relatively straightforward. We investigated the genetic origin of Phytophthora andina, an increasingly common pathogen of Andean crops Solanum betaceum, S. muricatum, S. quitoense, and several wild Solanum spp. It has been hypothesized that P. andina is a hybrid between the potato late blight pathogen P. infestans and another Phytophthora species. We tested this hypothesis by cloning four nuclear loci to obtain haplotypes and using these loci to infer the phylogenetic relationships of P. andina to P. infestans and other related species. Sequencing of cloned PCR products in every case revealed two distinct haplotypes for each locus in P. andina, such that each isolate had one allele derived from a P. infestans parent and a second divergent allele derived from an unknown species that is closely related but distinct from P. infestans, P. mirabilis, and P. ipomoeae. To the best of our knowledge, the unknown parent has not yet been collected. We also observed sequence polymorphism among P. andina isolates at three of the four loci, many of which segregate between previously described P. andina clonal lineages. These results provide strong support that P. andina emerged via hybridization between P. infestans and another unknown Phytophthora species also belonging to Phytophthora clade 1c.

Seed Potato Quality Improvement through Positive Selection by Smallholder Farmers in Kenya

Abstract: In Kenya, seed potato quality is often a major yield constraint in potato production as smallholder farmers use farm-saved seed without proper management of seed-borne pests and diseases. Farm-saved seed is therefore often highly degenerated. We carried out on-farm research to assess whether farmer-managed positive seed selection could improve yield. Positive selection gave an average yield increase in farmer-managed trials of 34%, corresponding to a 284-€ increase in profit per hectare at an additional production cost of only 6 €/ha. Positive selection can be an important alternative and complementary technology to regular seed replacement, especially in the context of imperfect rural economies characterized by high risks of production and insecure markets. It does not require cash investments and is thus accessible for all potato producers. It can also be applied where access to high-quality seed is not guaranteed. The technology is also suitable for landraces and not recognized cultivars that cannot be multiplied formally. Finally, the technology fits seamlessly within the seed systems of Sub-Saharan Africa, which are dominated by self-supply and neighbour supply of seed potatoes.

Multi-stakeholder platforms for linking small farmers to value chains: evidence from the Andes

Abstract: Value chains linked to urban markets and agro-industry present new opportunities for adding value and raising rural incomes. Small farmers, who produce small volumes, struggle to enter these markets. A lack of trust among value chain actors increases transaction costs and short-circuits innovation. This paper explores how multi-stakeholder platforms have been used to address these problems in potato-based value chains in Bolivia, Peru and Ecuador. It uses the Institutional Analysis and Development (IAD) framework to understand how platforms work. Differences in characteristics of the value chains, the participating actors and institutional arrangements have led to the emergence of two types of platforms. The first type brings traders, processors, supermarkets and others together with farmer associations and research and development (R&D) organizations to foster the development of new market opportunities through commercial, institutional and technological innovation. The second type is structured around g...

Modelling landslide hazard, soil redistribution and sediment yield of landslides on the Ugandan footslopes of Mount Elgon

Abstract: In this study, the LAPSUS-LS landslide model, together with a digital terrain analysis of topographic attributes, is used as a spatially explicit tool to simulate recent shallow landslides in Manjiya County on the Ugandan slopes of Mount Elgon. Manjiya County is a densely populated mountainous area where landslides have been reported since the beginning of the twentieth century. To better understand the causal factors of landsliding, 81 recent landslides have been mapped and investigated. Through statistical analysis it was shown that steep concave slopes, high rainfall, soil properties and layering as well as human interference were the main factors responsible for landslides in the study area. LAPSUS-LS is used to construct a landslide hazard map, and to confirm or reject the main factors for landsliding in the area. The model is specifically designed for the analysis of shallow landslide hazard by combining a steady state hydrologic model with a deterministic infinite slope stability model. In addition, soil redistribution algorithms can be applied, whereby erosion and sedimentation by landsliding can be visualized and quantified by applying a threshold critical rainfall scenario. The model is tested in the Manjiya study area for its ability to delineate zones that are prone to shallow landsliding in general and to group the recent landslides into a specific landslide hazard category. The digital terrain analysis confirms most of the causal topographic factors for shallow landsliding in the study area. In general, shallow landslides occur at a relatively large distance from the water divide, on the transition between steep concave and more gentle convex slope positions, which points to concentration of (sub)surface flow as the main hydrological triggering mechanism. In addition, LAPSUS-LS is capable to group the recent shallow landslides in a specific landslide hazard class (critical rainfall values of 0.03– 0.05 m day −1 ). By constructing a landslide hazard map and simulating future landslide scenarios with the model, slopes in Manjiya County can be identified as inherently unstable and volumes of soil redistribution can yield four times higher than currently observed. More than half of this quantity can end up in the stream network, possibly damming rivers and causing major damage to infrastructure or siltation and pollution of streams. The combination of a high population density, land shortage and a high vulnerability to landslides will likely continue to create a major sustainability problem. © 2007 Elsevier B.V. All rights reserved.

International Agricultural Research Tackling the Effects of Global and Climate Changes on Plant Diseases in the Developing World.

Abstract: Climate change has a number of observed, anticipated, or possible consequences on crop health worldwide. Global change, on the other hand, incorporates a number of drivers of change, including global population increase, natural resource evolution, and supply–demand shifts in markets, from local to global. Global and climate changes interact in their effects on global ecosystems. Identifying and quantifying the impacts of global and climate changes on plant diseases is complex. A number of nonlinear relationships, such as the injury (epidemic)–damage (crop loss) relationship, are superimposed on the interplay among the three summits of the disease triangle (host, pathogen, environment). Work on a range of pathosystems involving rice, peanut, wheat, and coffee has shown the direct linkage and feedback between production situations and crop health. Global and climate changes influence the effects of system components on crop health. The combined effects of global and climate changes on diseases vary from one pathosystem to another within the tetrahedron framework (humans, pathogens, crops, environment) where human beings, from individual farmers to consumers to entire societies, interact with hosts, pathogens, and the environment. This article highlights international phytopathological research addressing the effects of global and climate changes on plant diseases in a range of crops and pathosystems.

Ex ante assessment of dual-purpose sweet potato in the crop-livestock system of western Kenya: a minimum-data approach

Abstract: Mixed crop–livestock systems have a crucial role to play in meeting the agricultural production challenges of smallholder farmers in sub-Saharan Africa. Sweet potato is seen as a potential remedial crop for these farmers because of its high productivity and low input requirements, while its usefulness for both food and feed (dual-purpose) make it attractive in areas where land availability is declining. In this paper, we develop and apply a ‘minimum-data’ methodology to assess ex ante the economic viability of adopting dual-purpose sweet potato in Vihiga district, western Kenya. The methodology uses and integrates available socio-economic and bio-physical data on farmers’ land use allocation, production, and input and output use. Spatially heterogeneous characteristics of the current system regarding resources and productivity are analyzed to assess the profitability of substituting dual-purpose sweet potato for other crops currently grown for food and feed. Results indicate that a substantial number of farmers in the study area could benefit economically from adopting dual-purpose sweet potato. Depending on assumptions made, the adoption rate, expressed as the percentage of the total land under adopting farms, is between 55% and 80%. The analysis shows that the adoption rate is likely to vary positively with the average total yield of dual-purpose sweet potato, the harvest index (the ratio between tuber and fodder yields), the price of milk, and the nutritional value of available fodder. This study demonstrates the usefulness of the minimum-data methodology and provides evidence to support the hypothesis that dissemination of the dual-purpose sweet potato could help improve the livelihoods of smallholder farmers operating in mixed crop–livestock systems in east Africa.

Linking Smallholders to the New Agricultural Economy: The Case of the Plataformas de Concertación in Ecuador

Abstract: This article examines the challenges of linking smallholders to high-value food markets by looking at the experience of the Plataformas programme in the Ecuadorian Sierra. Multiple evaluation metho...

Combining chloroplast and nuclear microsatellites to investigate origin and dispersal of New World sweet potato landraces.

Abstract: We analysed a representative collection of New World sweet potato landraces (329 accessions from Mexico to Peru) with both chloroplast and nuclear microsatellite markers. Both kinds of markers supported the existence of two geographically restricted genepools, corresponding to accessions from the north-western part of South America and accessions from the Caribbean and Central America region. Our conservative cpSSRs markers revealed that the divergence between the two haplotype groups is associated with numerous mutation events concerning various markers, supporting the idea that this divergence may be ancient, predating domestication. For both kinds of markers, we found no significant difference in diversity between the two genepools and detected region-specific alleles in both groups. Previous studies have favoured the hypothesis of a single domestication of this crop. Our analysis suggests at least two independent domestications, in Central/Caribbean America and in the north-western part of South America. Sweet potato was then dispersed from these centres throughout tropical America. Comparison of nuclear and chloroplast data suggests that exchanges of clones and sexual reproduction were both important processes in landrace diversification in this clonally propagated crop. Our analysis provides useful tools for rationalizing the conservation and use of sweet potato germplasm collections.

Leafminer Fly (Diptera: Agromyzidae) Occurrence, Distribution, and Parasitoid Associations in Field and Vegetable Crops Along the Peruvian Coast

Abstract: Leafminer flies (Diptera: Agromyzidae) are important agricultural pests worldwide. The objective of our study was to assess the relative importance of agromyzids and their associated parasitoids in field and vegetable crops along the Peruvian coast. In total, nine leafminer fly species were identified in 27 crops. The most dominant species was Liriomyza huidobrensis (Blanchard) (88.0%). Liriomyza sativae Blanchard was the second most dominant species (8.59%) but mainly found in the most northern part of Peru. On average, a parasitism of 29.5% was registered by 63 parasitoids belonging to the families Eulophidae (41 spp.), Braconidae (11 spp.), Pteromalidae (8 sp.), Fitigidae (1 sp.), and Mymaridae (2 spp.). The endoparasitoids Halticoptera arduine (Walter) (48.2%), Chrysocharis flacilla Walker (19.5%), and C. caribea Boucek (8.0%) as well as the ectoparasitoid Diglyphus websteri (Crawford) (8.7%) were the most abundant parasitoids. H. arduine was not only the most abundant and efficient parasitoid but also parasitized all leafminer fly species in 25 crops. The wide adaptation of the parasitoids H. arduine, C. flacilla, C. caribea, D. websteri, D. begini, and Ganaspidium Weld sp. to different host plants and leafminer fly species indicates the potential use of those parasitoids for biological control programs. The high diversity of parasitoids supports the assumption that leafminer flies are of neotropical origin. The heavily pesticide-based pest management practices along the Peruvian coast should take more advantage of the richness of parasitoids by augmenting its efficacy through the adoption of integrated pest management.

An agriculture and health inter-sectorial research process to reduce hazardous pesticide health impacts among smallholder farmers in the Andes

Abstract: Background: The use of highly hazardous pesticides by smallholder farmers constitutes a classic trans-sectoral ‘wicked problem’. We share our program of research in potato and vegetable farming communities in the Andean highlands, working with partners from multiple sectors to confront this problem over several projects. Methods: We engaged in iterative cycles of mixed methods research around particular questions, actions relevant to stakeholders, new proposal formulation and implementation followed by evaluation of impacts. Capacity building occurred among farmers, technical personnel, and students from multiple disciplines. Involvement of research users occurred throughout: women and men farmers, non-governmental development organizations, Ministries of Health and Agriculture, and, in Ecuador, the National Council on Social Participation. Results: Pesticide poisonings were more widespread than existing passive surveillance systems would suggest. More diversified, moderately developed agricultural systems had lower pesticide use and better child nutrition. Greater understanding among women of crop management options and more equal household gender relations were associated with reduced farm pesticide use and household pesticide exposure. Involvement in more organic agriculture was associated with greater household food security and food sovereignty. Markets for safer produce supported efforts by smallholder farmers to reduce hazardous pesticide use. Participatory interventions included: promoting greater access to alternative methods and inputs in a store cosponsored by the municipality; producing less harmful inputs such as compost by women farmers; strengthening farmer organizations around healthier and more sustainable agriculture; marketing safer produce among social sectors; empowering farmers to act as social monitors; and using social monitoring results to inform decision makers. Uptake by policy makers has included: the Ecuadorian Ministry of Health rolling out pesticide poisoning surveillance modeled on our system; the Ecuadorian Association of Municipalities holding a national virtual forum on healthier agriculture; and the Ecuadorian Ministry of Agriculture promulgating restrictions on highly hazardous pesticides in June 2010.

Carbohydrate metabolism and cell protection mechanisms differentiate drought tolerance and sensitivity in advanced potato clones (Solanum tuberosum L.)

Abstract: In potatoes and many other crops, drought is one of the most important environmental constraints leading to yield loss. Development of drought-tolerant cultivars is therefore required for maintaining yields under climate change conditions and for the extension of agriculture to sub-optimal cropping areas. Drought tolerance mechanisms have been well described for many crop plants including Native Andean potato. However, knowledge on tolerance traits suitable for commercial potato varieties is scarce. In order to describe drought tolerance mechanisms that sustain potato yield under water stress, we have designed a growth-chamber experiment with two Solanum tuberosum L. cultivars, the more drought tolerant accession 397077.16, and the sensitive variety Canchan. After 21 days of drought exposure, gene expression was studied in leaves using cDNA microarrays. The results showed that the tolerant clone presented more differentially expressed genes than the sensitive one, suggesting greater stress response and adaptation. Moreover, it exhibited a large pool of upregulated genes belonging to cell rescue and detoxication such as LEAs, dehydrins, HSPs, and metallothioneins. Transcription factors related to abiotic stresses and genes belonging to raffinose family oligosaccharide synthesis, involved in desiccation tolerance, were upregulated to a greater extent in the tolerant clone. This latter result was corroborated by biochemical analyses performed at 32 and 49 days after drought that showed an increase in galactinol and raffinose especially in clone 397077.16. The results depict key components for the drought tolerance of this advanced potato clone.

Effect of storage conditions on microbiological and physicochemical quality of shea butter

Abstract: Storage conditions are key constraints for quality assurance of the shea (Vitellaria paradoxa Gaertner) butter. In the Sudan savannah Africa, storage conditions of butter produced by women vary across and among processors, traders and consumers. These conditions could impact the quality of the products and reduced their access to international market. The present study attempted to investigate the effect of storage duration and packaging materials on microbiological and physicochemical characteristics of shea butter under tropical climatic conditions. Five packaging materials traditionally used in shea butter value chain were tested for their efficacy in storing shea butter freshly produced. Total germs, yeasts and mould varied with packaging materials and storage duration. After 2 months of storage, moisture content of butter remained constant (5%) whereas acid value increased from 3.3 to 5.4 mg KOH/g, peroxide value from 8.1 to 10.1 meq O2/kg and iodine value dropped from 48.8 to 46.2 mg I2/100 g in shea butter irrespectively to the storage materials used. The basket papered with jute bag was the less effective in ensuring the quality of butter during storage while plastic containers and plastic bags seemed to be the best packaging materials.

Genetic Diversity in White- and Orange-Fleshed Sweetpotato Farmer Varieties from East Africa Evaluated by Simple Sequence Repeat Markers

Abstract: Sweetpotato [Ipomoea batatas (L.) Lam] farmer varieties are still the backbone of production and breeding programs in Sub-Sahara Africa. Usually, farmer varieties in Sub-Sahara Africa are white- or cream-fl eshed sweetpotato (WFSP), but recently orange-fl eshed sweetpotato (OFSP) were found in East Africa. The objective of the study was to characterize WFSP and OFSP germplasm from East Africa. Eighty-fi ve East African farmer varieties (29 OFSPs and 56 WFSPs) and seven varieties of non-African origin as check clones were analyzed for diversity using 26 simple sequence repeat (SSR) markers. A total of 158 alleles were scored with an average of 6.1 alleles per SSR loci. The mean of Jaccard’s similarity coeffi cients was 0.54. The unweighted pair group method analysis (UPGMA) revealed a main cluster for East Africa germplasm at a similarity coeffi cient of 0.52. At a similarity coeffi cient of about 0.55 subclusters within the East African germplasm were observed, but these were neither country nor fl esh color specifi c. Analysis of molecular variance (AMOVA) found a signifi cant difference between East African and non-African germplasm and a nonsignifi cant difference between OFSP and WFSP germplasm. In conclusion, the East African germplasm appears to be distinct from non-African germplasm, and OFSP and WFSP farmer varieties from East Africa are closely related. Orange-fleshed sweetpotato farmer varieties from East Africa might show similar adaptation to Sub-Sahara African environments as WFSP and a big potential in alleviating vitamin A deficiency.

Sweetpotato Seed Systems in Uganda, Tanzania, and Rwanda

Abstract: Surveys were made of the seed systems used in Uganda, Tanzania, and Rwanda and to investigate the reasons underlying them. Along the equator in Uganda, where rainy seasons are evenly spaced and occur twice a year, vine cuttings from mature plants only are used as planting material. Where there is a long dry season, the seed system includes a diversity of means of conservation: the passive production of volunteer plants from groundkeeper roots sprouting when the rains come; small-scale propagation of plants in the shade or backyard production using waste domestic water; and relatively large-scale propagation in wetlands or irrigated land. The last is the only means of obtaining sufficient quantity for sales, but is also the most expensive. Volunteers only produce planting material one or two months after the start of the rains and tend to be regarded as common property; nevertheless, they are an important source of planting material for poorer farmers. Although farmers perceive multiple benefits from plant...

Distinct cavemoviruses interact synergistically with sweet potato chlorotic stunt virus (genus Crinivirus) in cultivated sweet potato

Abstract: Two serologically unrelated sweet potato viruses causing symptoms of vein clearing in the indicator plant Ipomoea setosa were isolated and their genomes have been sequenced. They are associated with symptomless infections in sweet potato but distinct vein-clearing symptoms and higher virus titres were observed when these viruses co-infected with sweet potato chlorotic stunt virus (SPCSV), a virus that is distributed worldwide and is a mediator of severe virus diseases in this crop. Molecular characterization and phylogenetic analysis revealed an overall nucleotide identity of 47.6 % and an arrangement of the movement protein and coat protein domains characteristic of members of the genus Cavemovirus, in the family Caulimoviridae. We detected both cavemoviruses in cultivated sweet potato from East Africa, Central America and the Caribbean islands, but not in samples from South America. One of the viruses characterized showed a similar genome organization as, and formed a phylogenetic sublineage with, tobacco vein clearing virus (TVCV), giving further support to the previously suggested separation of TVCV, and related viral sequences, into a new caulimovirid genus. Given their geographical distribution and previous reports of similar but yet unidentified viruses, sweet potato cavemoviruses may co-occur with SPCSV more often than previously thought and they could therefore contribute to the extensive yield losses and cultivar decline caused by mixed viral infections in sweet potato.

A metamodeling framework for extending the application domain of process-based ecological models

Abstract: Process-based ecological models used to assess organisms' responses to environmental conditions often need input data at a high temporal resolution, e.g., hourly or daily weather data. Such input data may not be available at a high spatial resolution for large areas, limiting opportunities to use such models. Here we present a metamodeling framework to develop reduced form ecological models that use lower resolution input data than the original process models. We used generalized additive models to create metamodels for an existing model that uses hourly data to predict risk of potato late blight, caused by the plant pathogen Phytophthora infestans. The metamodels used daily or monthly weather data, and their predictions maintained the key features of the original model. This approach can be applied to other complex models, allowing them to be used more widely.

Potential use of the Bushmint, Hyptis suaveolens, for the Control of Infestation by the Pink Stalk Borer, Sesamia calamistis on Maize in Southern Benin, West Africa

Abstract: Maize production in Benin, especially in resource-poor farmers' fields, is constrained by stemborers among other factors. One of the major stemborers in southern Benin is Sesamia calamistis Hampson (Lepidoptera: Noctuidae). African farmers cannot afford to use commercial insecticides for controlling stemborers - they are expensive and unsuitable for durable pest management systems due to eco-toxicity. There is therefore a need for cheaper and environmentally friendly methods and botanicals offer an attractive alternative. The bushmint, Hyptis suaveolens (L.) Poit. (Lamiales: Lamiaceae), was compared with the commercial insecticide Furadan (carbofuran) for the control of S. calamistis on maize Zea mays L. (Poales: Poaceae). Trials were conducted in the screenhouse and in the field during the minor cropping season in 2004 at the International Institute of Tropical Agriculture (IITA)-Benin station. The variables measured included numbers of egg masses per plant, eggs per egg mass (in the screenhouse study), population density of S. calamistis, percentage of infested plants and/or ears, and deadhearts in the field. Irrespective of the variable considered, the aqueous extract of H. suaveolens compared favorably with Furadan while maize surrounded by live H. suaveolens plants had lower S. calamistis densities.

Cooperation-88: A high yielding, multi-purpose, late blight resistant cultivar growing in Southwest China.

Abstract: Cooperation-88 (C88) is a high yielding potato cultivar with durable resistance to Phytophthora infestans Mont. de Bary and excellent virus resistance. This has permitted the cultivar to rapidly increase its production area in Yunnan Province of China, as well as in neighboring provinces and countries. C88 is the result of a cross between I-1085, a clone from India selected for late blight (LB) resistance in Mexico and distributed by the International Potato Center (CIP), and a bulk pollen of a poorly adapted but highly LB resistant population with its origin in Solanum andigena from CIP Peru. C88 has excellent vegetative growth; it is late maturing under the long day summer growing season in Yunnan Province. It is much earlier maturing under the low elevation and warmer winter season of Yunnan. Experimental yields ranged from 23 to 55 t/ha, out-yielding the control cultivar Mira by 5% to 76%. Tuber quality is excellent, garnering a premium price in the markets. C88 has also become the preferred cultivar for the chipping potato industry, which uses medium-sized tubers, while the larger ones go for the fresh table market. Current estimates place the total area under production at 390,000 ha in Yunnan and its neighboring provinces, making C88 one of the most widely grown cultivars in the world today, less than 15 years after release.

Makers and Users of Geomorphological Maps

Abstract: In the last 60 years, geomorphology has been recognised as an important field serving several other professions. At the same time there are still limited resources spent on either national or regional geomorphological mapping programmes compared to geological, soil, land cover mapping programmes. From the maker's point of view, interesting exceptions in Europe are, for instance, the German, Austrian, Dutch, Spanish, and Italian national geomorphological mapping programmes. From the user's point of view, one of the strongest supporters of applied geomorphological mapping is the British Engineering Geological Community that has understood the added value of engineering geomorphological mapping and the economic savings in project developments when this practice is in place. In this scenario, it is the private sector – for instance the insurance sector – and the ecological community that have the highest potential of upscaling geomorphological mapping efforts. We review existing national geomorphological mapping efforts and further develop the needs of geomorphological mapping in natural hazards zonation and landscape planning.

Biogeographic Implications of the Striking Discovery of a 4,000 Kilometer Disjunct Population of the Wild Potato Solanum morelliforme in South America

Abstract: Solanum morelliforme is an epiphytic wild potato (Solanum section Petota) species widely distributed throughout central Mexico to Honduras. A strikingly disjunct (approximately 4,000 km) population was recently discovered in Bolivia, representing the first record of this species in South America, and the first species in the section growing in both North and Central America and in South America. Our maximum entropy analysis of 19 climatic variables matches the occurrence of the South American locality with great precision. It demonstrates the strong predictive quality of this procedure and suggests similar localities where this species may be found, especially along the eastern slopes of the Andes in the Yungas region of southern Peru and Bolivia. In addition, the presence of S. morelliforme in South America adds to emerging data from yet other sources to question long-held hypotheses of the origin of section Petota in North and Central America.