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Kumar P.L.,International Institute Of Tropical Agriculture | Selvarajan R.,National Research Center for Banana | Iskra-Caruana M.-L.,CIRAD - Agricultural Research for Development | Chabannes M.,CIRAD - Agricultural Research for Development | Hanna R.,IITA
Advances in Virus Research | Year: 2015

Banana and plantain (Musa spp.), produced in 10.3 million ha in the tropics, are among the world's top 10 food crops. They are vegetatively propagated using suckers or tissue culture plants and grown almost as perennial plantations. These are prone to the accumulation of pests and pathogens, especially viruses which contribute to yield reduction and are also barriers to the international exchange of germplasm. The most economically important viruses of banana and plantain are Banana bunchy top virus (BBTV), a complex of banana streak viruses (BSVs) and Banana bract mosaic virus (BBrMV). BBTV is known to cause the most serious economic losses in the "Old World," contributing to a yield reduction of up to 100% and responsible for a dramatic reduction in cropping area. The BSVs exist as episomal and endogenous forms are known to be worldwide in distribution. In India and the Philippines, BBrMV is known to be economically important but recently the virus was discovered in Colombia and Costa Rica, thus signaling its spread into the "New World." Banana and plantain are also known to be susceptible to five other viruses of minor significance, such as Abaca mosaic virus, Abaca bunchy top virus, Banana mild mosaic virus, Banana virus X, and Cucumber mosaic virus. Studies over the past 100 years have contributed to important knowledge on disease biology, distribution, and spread. Research during the last 25 years have led to a better understanding of the virus-vector-host interactions, virus diversity, disease etiology, and epidemiology. In addition, new diagnostic tools were developed which were used for surveillance and the certification of planting material. Due to a lack of durable host resistance in the Musa spp., phytosanitary measures and the use of virus-free planting material are the major methods of virus control. The state of knowledge on BBTV, BBrMV, and BSVs, and other minor viruses, disease spread, and control are summarized in this review. © 2015 Elsevier Inc.


Chikoye D.,International Institute Of Tropical Agriculture | Fontem L.A.,University of Buea | Menkir A.,IITA
Journal of Food, Agriculture and Environment | Year: 2011

Striga hermonthica is a serious threat to cereal production in the savannas of sub-Saharan Africa. Field trials were conducted in Nigeria at Abuja and Mokwa (southern Guinea savanna) in 2005 and 2006, and at Zaria (northern Guinea savanna) and Sabongari (Sudan savanna) in 2006, to evaluate the performance of imazapyr coated maize hybrids with the herbicide resistance (IR) gene under Striga infestation. Treatments were seven IR maize hybrids, and three checks without the IR gene (the commercial hybrid Oba Super 1, a Striga tolerant line 9022-13, and a Striga susceptible line 8338-1). The hybrids were either coated with imazapyr and sown under Striga infestation or uncoated and sown in Striga-free conditions. Across all locations, six of the IR maize hybrids were high-yielding under Striga infestation. Seed coating significantly reduced Striga emergence and damage to the maize plants at all locations. The Striga susceptible hybrid check, 8338-1, had a high level of Striga damage and sustained a yield loss of 99% when uncoated and sown under Striga infested conditions. In Striga-free plots, the checks had yields comparable to that of the seven IR maize hybrids. Significant negative correlations were detected between grain yield and Striga damage ratings (r p = -0.64) at Abuja and Mokwa. The findings indicate that seed coating IR maize hybrids with imazapyr was effective for Striga hermonthica control.


ST. LOUIS, MO, December 14, 2016-The Donald Danforth Plant Science Center announces that the Virus Resistant Cassava for Africa Plus (VIRCA Plus) consortium of American, Nigerian, Ugandan, and Kenyan institutions recently received a five-year, $10.46 million grant from the Bill & Melinda Gates Foundation to develop disease-resistant and nutritionally-enhanced cassava varieties to improve the livelihoods and health status of African farm families. Cassava is an important food and cash crop for small-holder farmers in Africa. It is the second most important staple food crop after maize in sub-Saharan Africa. Approximately one-third of the population relies on its starchy tuberous roots for over 50 percent of their daily caloric intake. It grows well in conditions of drought and low soil fertility prevalent in many African countries. However, plant viral diseases can destroy up to 100 percent of a cassava crop yield, threatening livelihoods and leading to hunger. Although it is an excellent source of calories, cassava does not contain significant levels of key nutrients to meet minimum daily requirements, especially for women and children. The VIRCA Plus collaboration will address these challenges by developing and delivering two products. The first will be East African cassava varieties with resistance to both Cassava Mosaic Disease (CMD) and Cassava Brown Streak Disease (CBSD). The second will be a Nigerian cassava variety with elevated levels of iron and zinc for improved nutrition, as well as disease resistance. VIRCA Plus builds on the success of two predecessor projects. The VIRCA project successfully developed strong and stable resistance to CBSD in cassava, validated over four field trials and multiple cropping cycles in Kenya and Uganda. The BioCassava Plus project succeeded in developing and testing cassava plants that accumulated greater than 10 times more iron and zinc than comparable varieties. Both minerals are retained after processing into common foodstuffs at levels that could provide 40-70 percent of the Estimated Average Requirement for vulnerable women and children. "By combining capacities and successes of the two predecessor projects, VIRCA Plus is poised to make important strides in improving agricultural productivity for farmers and enhancing nutrition for smallholder households in East and West Africa," said Nigel Taylor, Ph.D., Dorothy J. King Distinguished Investigator and Senior Research Scientist at the Donald Danforth Plant Science Center, and the principal investigator for VIRCA Plus. Partner institutes: The Donald Danforth Plant Science Center in St. Louis, MO, USA; the National Root Crops Research Institute (NRCRI) in Nigeria; the National Crop Resources Research Institute (NaCRRI)/ National Agricultural Research Organization (NARO) and the Science Foundation for Livelihoods and Development (SCIFODE) in Uganda; the Kenyan Agricultural and Livestock Research Organization (KALRO) and the ISAAA AfriCenter in Kenya; and the International Institute for Tropical Agriculture (IITA)in Nigeria. Founded in 1998, the Donald Danforth Plant Science Center is a not-for-profit research institute with a mission to improve the human condition through plant science. Research aims to feed the hungry and improve human health, preserve and renew the environment and position the St. Louis region as a world center for plant science. The Center's work is funded through competitive grants and contract revenue from many sources, including the National Institutes of Health, U.S. Department of Energy, National Science Foundation, U.S. Department of Agriculture, U.S. Agency for International Development, the Bill & Melinda Gates and Howard G. Buffett Foundations. Follow us on Twitter at @DanforthCenter.


ST. LOUIS, MO, December 16, 2016 /24-7PressRelease/ -- The Donald Danforth Plant Science Center announces that the Virus Resistant Cassava for Africa Plus (VIRCA Plus) consortium of American, Nigerian, Ugandan, and Kenyan institutions recently received a five-year, $10.46 million grant from the Bill & Melinda Gates Foundation to develop disease-resistant and nutritionally-enhanced cassava varieties to improve the livelihoods and health status of African farm families. Cassava is an important food and cash crop for small-holder farmers in Africa. It is the second most important staple food crop after maize in sub-Saharan Africa. Approximately one-third of the population relies on its starchy tuberous roots for over 50 percent of their daily caloric intake. It grows well in conditions of drought and low soil fertility prevalent in many African countries. However, plant viral diseases can destroy up to 100 percent of a cassava crop yield, threatening livelihoods and leading to hunger. Although it is an excellent source of calories, cassava does not contain significant levels of key nutrients to meet minimum daily requirements, especially for women and children. The VIRCA Plus collaboration will address these challenges by developing and delivering two products. The first will be East African cassava varieties with resistance to both Cassava Mosaic Disease (CMD) and Cassava Brown Streak Disease (CBSD). The second will be a Nigerian cassava variety with elevated levels of iron and zinc for improved nutrition, as well as disease resistance. VIRCA Plus builds on the success of two predecessor projects. The VIRCA project successfully developed strong and stable resistance to CBSD in cassava, validated over four field trials and multiple cropping cycles in Kenya and Uganda. The BioCassava Plus project succeeded in developing and testing cassava plants that accumulated greater than 10 times more iron and zinc than comparable varieties. Both minerals are retained after processing into common foodstuffs at levels that could provide 40-70 percent of the Estimated Average Requirement for vulnerable women and children. "By combining capacities and successes of the two predecessor projects, VIRCA Plus is poised to make important strides in improving agricultural productivity for farmers and enhancing nutrition for smallholder households in East and West Africa," said Nigel Taylor, Ph.D., Dorothy J. King Distinguished Investigator and Senior Research Scientist at the Donald Danforth Plant Science Center, and the principal investigator for VIRCA Plus. Partner institutes: The Donald Danforth Plant Science Center in St. Louis, MO, USA; the National Root Crops Research Institute (NRCRI) in Nigeria; the National Crop Resources Research Institute (NaCRRI)/ National Agricultural Research Organization (NARO) and the Science Foundation for Livelihoods and Development (SCIFODE) in Uganda; the Kenyan Agricultural and Livestock Research Organization (KALRO) and the ISAAA AfriCenter in Kenya; and the International Institute for Tropical Agriculture (IITA)in Nigeria. About The Donald Danforth Plant Science Center Founded in 1998, the Donald Danforth Plant Science Center is a not-for-profit research institute with a mission to improve the human condition through plant science. Research aims to feed the hungry and improve human health, preserve and renew the environment and position the St. Louis region as a world center for plant science. The Center's work is funded through competitive grants and contract revenue from many sources, including the National Institutes of Health, U.S. Department of Energy, National Science Foundation, U.S. Department of Agriculture, U.S. Agency for International Development, the Bill & Melinda Gates and Howard G. Buffett Foundations. Follow us on Twitter at @DanforthCenter.


International Collaboration Receives Grant to Advance Improvements in Cassava Harvests and Nutrition for Smallholder Families in Sub-Saharan Africa Virus Resistant Cassava for Africa Plus (VIRCA Plus) consortium received a five-year, $10.46 million grant to develop disease-resistant and nutritionally-enhanced cassava varieties to improve the status of African farm families. St. Louis, MO, December 16, 2016 --( Cassava is an important food and cash crop for small-holder farmers in Africa. It is the second most important staple food crop after maize in sub-Saharan Africa. Approximately one-third of the population relies on its starchy tuberous roots for over 50 percent of their daily caloric intake. It grows well in conditions of drought and low soil fertility prevalent in many African countries. However, plant viral diseases can destroy up to 100 percent of a cassava crop yield, threatening livelihoods and leading to hunger. Although it is an excellent source of calories, cassava does not contain significant levels of key nutrients to meet minimum daily requirements, especially for women and children. The VIRCA Plus collaboration will address these challenges by developing and delivering two products. The first will be East African cassava varieties with resistance to both Cassava Mosaic Disease (CMD) and Cassava Brown Streak Disease (CBSD). The second will be a Nigerian cassava variety with elevated levels of iron and zinc for improved nutrition, as well as disease resistance. VIRCA Plus builds on the success of two predecessor projects. The VIRCA project successfully developed strong and stable resistance to CBSD in cassava, validated over four field trials and multiple cropping cycles in Kenya and Uganda. The BioCassava Plus project succeeded in developing and testing cassava plants that accumulated greater than 10 times more iron and zinc than comparable varieties. Both minerals are retained after processing into common foodstuffs at levels that could provide 40-70 percent of the Estimated Average Requirement for vulnerable women and children. “By combining capacities and successes of the two predecessor projects, VIRCA Plus is poised to make important strides in improving agricultural productivity for farmers and enhancing nutrition for smallholder households in East and West Africa,” said Nigel Taylor, Ph.D., Dorothy J. King Distinguished Investigator and Senior Research Scientist at the Donald Danforth Plant Science Center, and the principal investigator for VIRCA Plus. Partner institutes: The Donald Danforth Plant Science Center in St. Louis, MO, USA; the National Root Crops Research Institute (NRCRI) in Nigeria; the National Crop Resources Research Institute (NaCRRI)/ National Agricultural Research Organization (NARO) and the Science Foundation for Livelihoods and Development (SCIFODE) in Uganda; the Kenyan Agricultural and Livestock Research Organization (KALRO) and the ISAAA AfriCenter in Kenya; and the International Institute for Tropical Agriculture (IITA)in Nigeria. About The Donald Danforth Plant Science Center Founded in 1998, the Donald Danforth Plant Science Center is a not-for-profit research institute with a mission to improve the human condition through plant science. Research aims to feed the hungry and improve human health, preserve and renew the environment and position the St. Louis region as a world center for plant science. The Center’s work is funded through competitive grants and contract revenue from many sources, including the National Institutes of Health, U.S. Department of Energy, National Science Foundation, U.S. Department of Agriculture, U.S. Agency for International Development, the Bill & Melinda Gates and Howard G. Buffett Foundations. Follow us on Twitter at @DanforthCenter. St. Louis, MO, December 16, 2016 --( PR.com )-- The Donald Danforth Plant Science Center announces that the Virus Resistant Cassava for Africa Plus (VIRCA Plus) consortium of American, Nigerian, Ugandan, and Kenyan institutions recently received a five-year, $10.46 million grant from the Bill & Melinda Gates Foundation to develop disease-resistant and nutritionally-enhanced cassava varieties to improve the livelihoods and health status of African farm families.Cassava is an important food and cash crop for small-holder farmers in Africa. It is the second most important staple food crop after maize in sub-Saharan Africa. Approximately one-third of the population relies on its starchy tuberous roots for over 50 percent of their daily caloric intake. It grows well in conditions of drought and low soil fertility prevalent in many African countries. However, plant viral diseases can destroy up to 100 percent of a cassava crop yield, threatening livelihoods and leading to hunger. Although it is an excellent source of calories, cassava does not contain significant levels of key nutrients to meet minimum daily requirements, especially for women and children.The VIRCA Plus collaboration will address these challenges by developing and delivering two products. The first will be East African cassava varieties with resistance to both Cassava Mosaic Disease (CMD) and Cassava Brown Streak Disease (CBSD). The second will be a Nigerian cassava variety with elevated levels of iron and zinc for improved nutrition, as well as disease resistance.VIRCA Plus builds on the success of two predecessor projects. The VIRCA project successfully developed strong and stable resistance to CBSD in cassava, validated over four field trials and multiple cropping cycles in Kenya and Uganda. The BioCassava Plus project succeeded in developing and testing cassava plants that accumulated greater than 10 times more iron and zinc than comparable varieties. Both minerals are retained after processing into common foodstuffs at levels that could provide 40-70 percent of the Estimated Average Requirement for vulnerable women and children.“By combining capacities and successes of the two predecessor projects, VIRCA Plus is poised to make important strides in improving agricultural productivity for farmers and enhancing nutrition for smallholder households in East and West Africa,” said Nigel Taylor, Ph.D., Dorothy J. King Distinguished Investigator and Senior Research Scientist at the Donald Danforth Plant Science Center, and the principal investigator for VIRCA Plus.Partner institutes: The Donald Danforth Plant Science Center in St. Louis, MO, USA; the National Root Crops Research Institute (NRCRI) in Nigeria; the National Crop Resources Research Institute (NaCRRI)/ National Agricultural Research Organization (NARO) and the Science Foundation for Livelihoods and Development (SCIFODE) in Uganda; the Kenyan Agricultural and Livestock Research Organization (KALRO) and the ISAAA AfriCenter in Kenya; and the International Institute for Tropical Agriculture (IITA)in Nigeria.About The Donald Danforth Plant Science CenterFounded in 1998, the Donald Danforth Plant Science Center is a not-for-profit research institute with a mission to improve the human condition through plant science. Research aims to feed the hungry and improve human health, preserve and renew the environment and position the St. Louis region as a world center for plant science. The Center’s work is funded through competitive grants and contract revenue from many sources, including the National Institutes of Health, U.S. Department of Energy, National Science Foundation, U.S. Department of Agriculture, U.S. Agency for International Development, the Bill & Melinda Gates and Howard G. Buffett Foundations. Follow us on Twitter at @DanforthCenter. Click here to view the list of recent Press Releases from Donald Danforth Plant Science Center


Valbuena D.,System Wide Livestock Programme | Valbuena D.,Wageningen University | Tui S.H.K.,ICRISAT | Erenstein O.,CIMMYT | And 7 more authors.
Agricultural Systems | Year: 2015

Crop residues (CR) have become a limited resource in mixed crop-livestock farms. As a result of the increasing demand and low availability of alternative resources, CR became an essential resource for household activities, especially for livestock keeping; a major livelihood element of smallholder farmers in the developing world. Farmers' decisions on CR use are determined by farmers' preferences, total crop production, availability of alternative resources and demand for CR. Interaction of these determinants can result in pressures and trade-offs of CR use. Determinants, pressures and trade-offs are shaped by the specific socio-economic and agro-ecological context of these mixed farms. The objective of this paper is to provide a comparative analysis of the determinants of CR use and to examine some options to cope with pressures and trade-offs in 12 study sites across Sub-Saharan Africa and South Asia. Drawing on socio-economic data at household and village level, we describe how cereal intensification and livestock feed demand influence use, pressures and trade-offs of CR use across study sites, specifically cereal residue. Our results show that in low cereal production and livestock feed demand sites, despite a low demand for CR and availability of alternative biomass, pressures and trade-offs of CR use are common particularly in the dry season. In sites with moderate cereal production, and low-moderate and moderate livestock feed demand, alternative biomass resources are scarce and most residues are fed to livestock or used to cover household needs. Subsequently, pressures and potential trade-offs are stronger. In sites with low cereal production and high livestock feed demand, pressures and trade-offs depend on the availability of better feed resources. Finally, sites with high cereal production and high livestock feed demand have been able to fulfil most of the demand for CR, limiting pressures and trade-offs. These patterns show that agricultural intensification, better management of communal resources and off-farm activities are plausible development pathways to overcome pressures and trade-offs of CR use. Although technologies can largely improve these trends, research and development should revisit past initiatives so as to develop innovative approaches to tackle the well-known problem of low agricultural production in many smallholder mixed systems, creating more sustainable futures. © 2014 The Authors.


Karasev A.V.,University of Idaho | Nikolaeva O.V.,University of Idaho | Hu X.,University of Idaho | Sielaff Z.,University of Idaho | And 3 more authors.
American Journal of Potato Research | Year: 2010

In the course of a multi-year survey of Potato virus Y (PVY) incidence and diversity in the U. S. seed potato crop, an unusual PVY variant was identified in low but significant levels in multiple states. This variant, PVYO-O5, was initially detected by a commercially available PVYN-specific monoclonal antibody, 1F5. This antibody is widely used by U. S. Seed Certification programs to test for PVYN and is one of two antibodies designated by the North American Plant Protection Organization (NAPPO) for pre-shipment testing of tuber lots that are to be transported between countries. Consequently, PVYN positives identified by the 1F5 antibody have triggered quarantine actions, prevented cross-border shipments and impacted trade. Here, we demonstrate by a variety of methods that the PVYO-O5 is a variant within the ordinary PVY strain (PVYO). Specifically, the PVYO-O5 variant likely arose due to a single amino acid substitution within the capsid protein. This variant does not induce vein necrosis in tobacco or tuber necrosis in susceptible varieties of potato. Furthermore, it is identified by RT-PCR based diagnostics as PVYO and it has a typical PVYO genome sequence. We demonstrate that another PVYN specific monoclonal antibody, SASA-N, recognizes an epitope distinct from that recognized by 1F5, and correctly identifies the PVYO-O5 variants as belonging to the PVYO serotype. Since the PVYO-O5 variant is present in many seed producing states and misidentification of PVYO-O5 as PVYN/NTN has clear quarantine implications for export shipments of potato, the limitations of the commercially available monoclonal antibodies should be considered in any certification or phytosanitary testing program. © Potato Association of America 2009.


Lambrecht I.,Ghana Food Research Institute | Vanlauwe B.,IITA | Maertens M.,Catholic University of Leuven
International Journal of Agricultural Sustainability | Year: 2016

Many paradigms on sustainable agricultural intensification promote a combination of different agricultural technologies. Whether such a paradigm survives in practice depends on how farmers combine these technologies on their fields. We focus on integrated soil fertility management (ISFM) and investigate how the concept is put into practice in South-Kivu, Eastern DR Congo. ISFM includes the use of improved germplasm, organic inputs and mineral fertilizer, and emphasizes the complementarities and synergies that arise when technologies are jointly applied. We investigate whether different ISFM components are applied jointly, sequentially or independently, and whether that matters for the long-term use of the technology. We use original survey data from 420 farms, and combine a descriptive statistical analysis and a factor analysis. We find that few farmers in the area have reached ‘full ISFM’, and technology application occurs sequentially rather than simultaneously. Two technology subsets can be distinguished: more resource-intensive and less resource-intensive technologies. These subsets behave as supplements rather than as complements, and adoption within and among each subset is more sequential than simultaneous. Our results imply that there is a disconnect between the theoretical arguments in the agronomic ISFM literature, and the actual patterns of ISFM application on farmers’ fields. © 2015 Taylor & Francis.


Valbuena D.,Systemwide Livestock Programme | Erenstein O.,CIMMYT | Homann-Kee Tui S.,ICRISAT | Abdoulaye T.,IITA | And 9 more authors.
Field Crops Research | Year: 2012

Conservation Agriculture (CA) is being advocated to enhance soil health and sustain long term crop productivity in the developing world. One of CA's key principles is the maintenance of soil cover often by retaining a proportion of crop residues on the field as mulch. Yet smallholder crop-livestock systems across Africa and Asia face trade-offs among various options for crop residue use. Knowledge of the potential trade-offs of leaving more residues as mulch is only partial and the objective of this research is to address some of these knowledge gaps by assessing the trade-offs in contrasting settings with mixed crop-livestock systems. The paper draws from village surveys in 12 sites in 9 different countries across Sub-Sahara Africa and South Asia. Sites were clustered into 3 groups along the combined population and livestock density gradients to assess current crop residue management practices and explore potential challenges to adopting mulching practices in different circumstances. Results show that although high-density sites face higher potential pressure on resources on an area basis, biomass production tends to be more substantial in these sites covering demands for livestock feed and allowing part of the residues to be used as mulch. In medium-density sites, although population and livestock densities are relatively lower, biomass is scarce and pressure on land and feed are high, increasing the pressure on crop residues and their opportunity cost as mulch. In low-density areas, population and livestock densities are relatively low and communal feed and fuel resources exist, resulting in lower potential pressure on residues on an area basis. Yet, biomass production is low and farmers largely rely on crop residues to feed livestock during the long dry season, implying substantial opportunity costs to their use as mulch. Despite its potential benefit for smallholder farmers across the density gradient, the introduction of CA-based mulching practices appears potentially easier in sites where biomass production is high enough to fulfil existing demands for feed and fuel. In sites with relatively high feed and fuel pressure, the eventual introduction of CA needs complementary research and development efforts to increase biomass production and/or develop alternative sources to alleviate the opportunity costs of leaving some crop residues as mulch. © 2012 Elsevier B.V.


Ferguson M.,Kenya International Livestock Research Institute | Rabbi I.,IITA | Kim D.-J.,Kenya International Livestock Research Institute | Gedil M.,IITA | And 2 more authors.
Tropical Plant Biology | Year: 2012

The advent of relatively low-cost, massively parallel, high-throughput genome sequencing and the resultant availability of high density markers are revolutionizing the ways in which molecular markers can be applied to plant breeding. With the availability of the draft cassava genome sequence, the cassava community is poised to take advantage of these new tools. Here we review the development of molecular markers applied to cassava breeding and describe the achievements that have been made using predominantly simple sequence repeat (SSR) markers. At this time of change, we report on the curation of 3,367 published and unpublished SSR primer pairs and provide a non-redundant database. We also describe ways in which new tools, particularly single nucleotide polymorphism (SNP) markers, can be applied to the development of high density maps and to fine mapping, association mapping, gene discovery, transcript profiling, inbred line development and the prediction of heterosis, gene mining in wild species and introgressions, and genome-wide approaches, including marker-assisted recurrent selection (MARS) and genomic selection (GS). Where applicable we describe how these tools are already being applied for amassing genetic gain in cassava. © 2011 Springer Science+Business Media, LLC.

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