• Sweetpotato: A Sleeping Giant
• Controlling Potato Late Blight
• Integrated Control of Bacterial Wilt
• Control of Potato Viruses
• True Potato Seed (TPS)
• Natural Resources and the Environment
• Outlook for 2000

CIP’s project-based research management approach, which devolved decision-making to CIP project teams, marked its second year in 1999. The new approach gave project leaders greater knowledge of day-to-day operations and—through their interaction with colleagues at national research organizations in developing countries—provided a natural mechanism for bringing CIP’s research partners into the process at an early stage.

Space does not permit a thorough description of all of CIP’s research achievements during 1999—which will be published in detail in the 1999–2000 Program Report. The most significant results, summarized below, show the progress CIP has made in meeting the research milestones established as Center goals for the 1998–2000 period.

Sweetpotato: A Sleeping Giant

Recent updates in commodity analysis show the crop recovering some of the glory it lost with the demise of its role as a food supplement during World War II. Global production has increased steadily over the past five years, and CIP’s recent analysis indicates that in the near future sweetpotato will contribute more to the global food system as a source of starch and animal feed in Asia. It will also grow in importance as a source of vitamin A in Africa. The Center has designed specific materials to meet these objectives in both target markets.

Our work with commercial processors indicates that dry-matter increases of 25 percent or more will place sweetpotato in a highly competitive position against major sources of cereal-based starch and animal feed. Breeding for high dry-matter content in sweetpotatoes has been very successful at CIP. Improved germplasm that produces sweetpotatoes with 38 percent dry matter (versus the typical dry matter level below 30 percent) and disease resistance has been distributed and is now used in national breeding programs or evaluated on its own. Twenty-one promising clones are currently being tested in farm trials, and a group of high dry-matter and root-rot nematode-resistant clones developed by CIP in Indonesia are being used widely by Chinese breeding programs. CIP partners have also released a new cultivar in India.

These breeding programs have also been successful in incorporating molecular methods. The first amplified fragment length polymorphism (AFLP) linkage map was developed for an important African traditional cultivar, and transgenic plants have been produced that express the soybean trypsin-inhibitor gene, which may provide resistance to the sweetpotato weevil—the crop’s most damaging pest worldwide.

Postharvest utilization of sweetpotato in Asia centers on the increased use of starch, flour, and vines for animal feed as well as new uses for fresh roots. An improved procedure for processing the starch of sweetpotato roots has been developed, and a new process for fermenting sweetpotato vines has increased protein content by 21 percent while reducing costs by half.

The most significant outcome, however, is the successful use of sweetpotato to address vitamin A deficiency in sub-Saharan Africa. Market research indicates that, with the right texture and flavor, orange-flesh sweetpotatoes are acceptable to sub-Saharan African consumers and can provide beta-carotene, the dietary precursor for vitamin A production. These varieties will be made more attractive to African farmers by incorporating resistance to weevils.

This market-oriented breeding work is accompanied by important improvements in crop management designed to further reduce product cost. CIP is collaborating in a global project to study sweetpotato decline caused by viruses. CIP has supplied virus antibodies as well as improved NCM-ELISA detection kits to worldwide collaborators to ensure the use of consistent techniques.

This work is stimulated by the outstanding results achieved in collaborative work with Chinese colleagues, which indicated a substantial economic impact from the diffusion of virus-free sweetpotato planting material in Shandong Province. Between 1994 and 1998, this material was disseminated to about 80 percent of the province’s total sweetpotato area. Since then, the material has also been distributed in other important sweetpotato-producing provinces in China. As a result of this work, sweetpotato yield in China has increased by 30 percent (versus 3 percent worldwide). The estimated internal rate of return for this research and extension program is 202 percent, with a net present value of US$550 million.

Important results have been gleaned from CIP’s IPM research in Cuba, Uganda, and Indonesia. Implementation of biological control–based integrated pest management (IPM) of the sweetpotato weevil in Cuba decreased storage root damage from more than 50 percent to less than 5 percent, while increasing yield by 30 percent. Results from a pilot project in Uganda indicated that farmers will only adopt IPM components if they generate short-term cash income. And monitoring and evaluation activities in Indonesia showed the potential impact of Farmer Field Schools for IPM of sweetpotatoes. Preliminary results indicate increased net return due to higher yields and lower production costs. Results will be validated in 2000.

Controlling Potato Late Blight

Late blight of potato is a devastating disease worldwide. In developing countries, the lack of a winter period and the continuous presence of host plants create the ongoing disease pressure belied in late blight’s name. Disease onset can be immediate after emergence. Under these conditions, the disease does not spread from isolated infection points, as in Europe and North America, but emanates en masse over large areas, moving at a devastating speed. Resource-poor farmers in East Africa, South and East Asia, and the Andean region are least likely to be able to afford the inputs necessary to control the disease with fungicide. Reaching and helping these farmers is the objective of CIP’s late blight project. The strategy is to fight the disease by providing farmers and extensionists with control practices that can be customized for local conditions.

CIP is also developing and distributing potato germplasm with long-lasting resistance against all forms of the pathogen, learning more about the pathogen itself, and working directly with farmers to help them understand the disease. In 1999, CIP’s resistant potato clones were distributed to many countries and performed well. Three late blight–resistant CIP-based varieties were released in Uganda and two in Peru.

CIP scientists also made significant progress in 1999 in the use of molecular tools to identify new sources of resistance and to facilitate transfer of the resistance to acceptable clones. At least one gene that may confer resistance has been isolated in a related species and cloned for creating transgenic plants carrying the resistance.

Increased knowledge of the late blight pathogen’s ecology and evolution—gained through epidemiological and genetic studies in Latin America and Africa—is offering greater understanding of its newer forms as well as its emerging resistance to fungicide. This knowledge is critical in determining which control components should be used at each particular site.

Farmers are benefiting directly from CIP’s efforts through the establishment of Farmer Field Schools, which were launched in seven countries in 1999 and now reach hundreds of farmers and their families. Farmers learn what causes late blight, a disease that is often attributed to excessive rainfall, sun, or mystical causes. They learn how to recognize the disease in its early stages and how to choose and use the best control methods for their local conditions. In the process, they further research progress by providing new information to scientists.

Integrated Control of Bacterial Wilt

The ELISA kit developed in 1998 to detect the bacterial wilt bacterium in potato tubers has been distributed to 24 countries, where it is used for seed certification and for quarantine and research purposes to support integrated disease management. In Southwest Asia, Farmer Field Schools are being used to orient farmers to aspects of integrated disease management for control of bacterial wilt and production of good quality seed. More than 200 farmers have attended the schools. The improved ELISA diagnostic tool also allowed increased emphasis in 1999 on characterizing germplasm for possible resistance. In Peru, 57 advanced clones were identified as having some resistance to bacterial wilt as well as desirable agronomic features. Eleven clones had less than 20 percent tuber latent infection. In wild species, accessions of 4 out of 8 species found to be resistant to wilt (S. acaule, S. circaeifolium, S. limbaniense, and S. sawyeri) did not harbor the bacteria in plant stems after greenhouse inoculation with race 3 of the pathogen.

Control of Potato Viruses

Many years of cooperation with The Sainsbury Laboratory (Norwich, UK) have laid the framework for improving clonal seed for resource-poor farm communities. A gene for resistance to potato virus Y has been located, isolated, and cloned for inserting into potato varieties through transformation. The Ry gene—known as the "resistance gene"—is unique in that it is naturally occurring in a species closely related to potato. A similar gene for resistance to potato virus X (PVX) has already been transferred to PVX-susceptible varieties through transformation. These varieties are now being evaluated to see if their resistance is sufficient to protect them against the virus. This development is of particular interest to poor farmers who depend on locally produced or stored seed tubers. Virus resistance will fortify these clonal seed sources and enable them to maintain resistance in the years ahead. This work may also reduce the need for seed producers to migrate to upper watershed areas in attempts to avoid the virus vectors. Such an effect would help protect important water-regulating mountain ecologies in tropical regions.

True Potato Seed (TPS)

Stable and consistent true potato seed hybrids are now available and being tested in many parts of the world. TPS offers alternatives to farmers without access to conventional high-quality seed tubers. It is also being used more and more as a rapid response technology for disaster mitigation and food production. In 1999, for example, CIP provided TPS on an emergency basis to North Korea and to the Caribbean countries devastated by Hurricane Mitch.

Unlike conventional seed tubers, TPS can be shipped easily and in small volumes, and management techniques can be taught quickly to farmers. Rapid food production is the result. CIP anticipates that the use of TPS for disaster mitigation and recovery will increase.

Natural Resources and the Environment

CIP’s work in natural resources and the environment has focused on a few main objectives: developing tools for improving watershed analysis and the evaluation and planning of land-use systems; identifying the role of crop–livestock systems; limiting damage from seed production and chemical pest control in high-mountain ecologies; and developing technologies, policies, and approaches for enterprise development in market-oriented production and post-production activities. In the commodity area, this focus leads to rigorous research in the area of crop biodiversity to reduce dependence on toxic chemicals for crop production and to explore the potential use of biological processes for crop management. In general, CIP’s natural resource management (NRM) work stresses the development and application of tools that identify the potential to reduce losses and protect the quality of the resource base (see NRM at CIP).

In 1999, our work in the Andes continued to develop minimum data sets to improve natural resource conservation in the Andes, an approach that has been welcomed by natural resource management experts. In addition, two software prototypes for integrated assessment of agroecosystems were developed: a decision-support system for agriculture (the "tradeoff model") and an integrated multiscale assessment system ("SIMSRIG") based on GIS, remote sensing, and process-based models. The main constraints related to productivity, poverty reduction, and the use of natural resources in CONDESAN’s benchmark sites were identified. As a part of CONDESAN’s systems approach, quinoa varieties with tolerance to frost and drought in Andean production systems were developed. Further progress was made in identifying commercial markets for processed Andean root and tuber products such as arracacha sweets and freeze-dried olluco.

In the area of conservation and characterization of potato genetic resources, CIP’s efforts to collect and safeguard Solanum species continue with 17 previously unavailable taxa of Peruvian Solanum collected in 1999. In conservation work, biodiversity surveys in communities in central Peru indicate a serious problem with genetic erosion of native potato cultivars. Communal seed banks are now being established to stem the erosion. Characterization and evaluation of native genetic materials continues. Twenty-three potato cultivars were identified as "drought-adaptive" and 15 native potato cultivars were identified as having desirable culinary qualities.

Outlook for 2000

There is no doubt that the research highlighted above is closely in line with the milestones CIP set for its 17 projects. While we expect further adjustment and consolidation in our research program during 2000, the results described above lay a solid foundation for applying technological change at the community level.