Abstract

We completed consensus disease QTL maps for rice and maize, identified regions of the maize genome that show shifts in allele frequency under recurrent selection, and made progress towards the development of near-isogenic lines for disease QTLs in maize.

Issue

The most environmentally friendly and sustainable way to manage most crop diseases is through the use of quantitative disease resistance. Identification and analysis of chromosomal regions that provide durable and broad-spectrum disease resistance will enhance our understanding of host-pathogen interactions and allow for better disease management. Northern corn leaf blight and gray leaf spot are important diseases of corn both in the United States and in Africa, where we work. We hope to provide fundamental insights into the nature of resistance and to help farmers avoid losses.

Response

Our research program has four main components that are aimed at identifying, characterizing, and using genes for quantitative disease resistance in cereal crops. These are: consensus mapping of existing bodies of data of relevance to disease resistance; identification of outstanding sources of resistance alleles in crop germplasm, including populations subjected to recurrent selection; development of genetic stocks, with a focus on near-isogenic lines; and utilization of superior alleles in practical breeding programs, particularly in Africa. We have made significant progress in each of these areas.

Impact

While field-level impact has not yet been achieved from our genetics program, we have been able to clarify some basic questions with regard to disease resistance and have facilitated the effectiveness of two applied programs with which we collaborate. Our paper bringing together a large body of evidence on disease resistance in rice was accepted in GENETICS and was hailed by collaborators at The International Rice Research Institute as a milestone with important practical implications. Together with a graduate student, I have spent time in Kenya to support our collaborators there. This has facilitated their marker-based genetic studies.

Funding Sources

• Private (e.g., commodity groups, foundations, companies)

Topic Description

• International agriculture

Collaborators

• Margaret Smith's group, Cornell.
• Steve Kresovich, IGD, Cornell.
• Peter Balint Kurti, USDA-ARS, North Carolina State University.
• Jane Ininda, Jedidah Danson and James Gethi, Kenya Agricultural Research Institute, Kenya.

Key Personnel

• Ying Wei, research support specialist, Plant Pathology-Ithaca, Cornell.
• Randy Wisser, grad student, Plant Breeding and Genetics, Cornell.
• Chia-Lin Chung
• graduate student, Plant Pathology-Ithaca, Cornell