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United States Department of Agriculture

Agricultural Research Service

Research Project: Aflatoxin Genetic Resistance in Maize

Location: Corn Host Plant Resistance Research

Project Number: 6406-21000-013-13
Project Type: Specific Cooperative Agreement

Start Date: Sep 30, 2012
End Date: Sep 17, 2014

Objective:
The objective of this project is to further validate new inbred lines displaying high and stable resistance to A. flavus and aflatoxin accumulation in new environments, and test which will be adapted to African growing conditions and disease pressures. Germplasm and genes will be sent to maize breeders in ongoing breeding programs to develop resistant varieties for developing world farmers within three years. In addition to adaptation, specific and general combining ability will be tested, and information on performance of the lines in hybrid combinations in different environments will be made publically available to maize breeders and small seed companies in Africa.

Approach:
Considerable work has already been done in the mapping of aflatoxin and A. flavus resistance in maize, and breeding lines that show stable and consistent resistance are currently available for this project. Breeding lines from the CHPRRU will be field tested in various hybrid combinations and to form new synthetics to enhance resistance to aflatoxin accumulation in existing African maize germplasm. In the first year, a design II mating scheme will be used to generate hybrids with the CHPRRU donor lines. The resulting hybrids will be evaluated in multiple locations under naturally occurring A. flavus infection in the second growing season of the first year to generate information on combining ability of the lines for yield and resistance to aflatoxin production; ears from the hybrids will be tested for aflatoxin levels using an ELISA assay. The information will be useful to form synthetics, identify the best donor lines for African breeding programs, and select potential crosses that can be backcrossed to an adapted lines to generate source populations to develop new generation of inbred lines with much higher levels of resistance to aflatoxin accumulation. The hybrids will also be evaluated under controlled drought stress during the second year. Synthetics will be formed in the third year, which can be used directly as cultivars for farmers in parts of the world where aflatoxin poisoning has been an ongoing and serious problem, or can be used by breeders to extract new resistant inbred lines with good agronomic performance and local adaptation, via Marker Assisted Selection using markers linked to resistance genes from the CHPRRU. The synthetics will be field tested and varieties released after the third year.

Last Modified: 7/31/2014
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