Farmers need to grow crops that will produce reliable, profitable, and healthful harvests with a minimum of detrimental or expensive inputs. Genetic resources provide the safest and most economical source of protection from the specific pests, diseases, and abiotic stresses that challenge food security.

However, scientists face a major obstacle in their efforts to use genetic resources to solve production constraints due to inadequate knowledge of the ways in which different sources of desired traits, and the genes they carry, interact to control crop performance. Indeed, most traits that are critical to agriculture are controlled by complex gene networks, which are in turn affected by the environment.

The discovery of new genes, and the development of more precise information and tools to guide their use, is thus a critical step toward continuing improvements in crop protection and productivity. Once better understood, traits controlled by single or multiple genes from close or more distant genetic resources can be incorporated into new varieties by a combination of conventional and biotechnological methods. This project seeks to bring genetic resources to bear on potato and sweetpotato production needs by confirming and characterizing new sources of needed traits, and developing information, stocks, and tools to optimize their use in breeding through classical and molecular genetic approaches.

GOALS. The project is devoted specifically to broadening the genetic base of resistance to late blight, viruses, and bacterial wilt in improved potato varieties and enhancing the efficiency of producing edible and profitable yields of root and tuber crops.

The project emphasizes the use of molecular tools and information to support genetic improvements. Strategic research, largely in collaboration with national partners and using multidisciplinary approaches to ensure appropriate evaluation methods, will help to identify, describe, and enhance access to new genetic diversity, and achieve rapid advance toward breeding goals and the development of adapted resistant varieties.

Sources of resistance will be catalogued, characterized, and enhanced to optimize their impact on crop improvement. Carbohydrate gene networks controlling yield and quality will also be explored and manipulated to benefit sweetpotato and potato productivity, postharvest utilization, and nutritional and market value. The project will continue to develop CIP’s advanced breeding population for virus resistance, and the identification of stable potato varieties for lower input crops that meet traditional and new utilization needs and opportunities in developing countries.

OUTPUT. This project serves as a source of new diversity, elite selections, and molecular tools for root and tuber crop breeding and variety development. Some of the specific outputs of the project include:

• identification and characterization of sources of priority traits
• genetic information, unique constructs, and enhanced stocks for use in potato and sweetpotato breeding programs
• location on gene maps of neutral markers, genes for resistance to potato late blight and viruses, productivity and quality factors, and development of molecular tools and strategies for their efficient use in breeding programs
• development of improved populations, elite progenitors of resistance to late blight and potato viruses, and advanced clones for use in breeding and production in developing country contexts
• identification and dissemination of advanced clones with resistance to bacterial wilt
• enhanced capacity of research programs to recognize and manipulate genetic diversity by conventional and biotechnological approaches

Genetic transformation provides complementary strategies for crop improvement.

The technologies developed and knowledge acquired will facilitate genetic improvement of root and tuber crops. National programs will have increased probabilities of selecting and releasing diverse, adapted resistant varieties through collaboration with this and other CIP projects.

IMPACT. Project activities will lead to advances in research methods, trained researchers, efficiencies within crop improvement programs, and greater recognition of the value of national and international public goods (e.g. genetic resources). The broader genetic base of resistance resulting from project activities will contribute to reducing pesticide use, increasing and stabilizing potato yields in tropical highlands and subtropical lowlands, and expanding the potato farming areas in tropical highlands. Through inputs to various other CIP projects and national programs, the project will have major impact in developing countries worldwide.

• Financial benefits may be of the order of US$530/ha in areas affected by each target disease or pest.
• Low-income farmers can expect yield increases of more than 15%, and seed-importing countries may enjoy lower seed costs.
• The use of potent progenitors of needed traits and more precise selection tools will enhance the efficiency of potato and sweetpotato breeding programs.
• The use of varieties with better quality and adaptability to marginal environments will help enhance potato production and assure the sustainability and competitivity of sweetpotato- and potato-based farming and utilization systems.
• The incorporation of new genetic materials into breeding programs and crop varieties will contribute to the conservation of biodiversity and the resilience of production systems.

For more information, please contact Meredith Bonierbale, Germplasm Enhancement and Crop Improvement Division Leader, Apartado 1558, Lima 12, Peru, or at m.bonierbale@cgiar.org