Identification of Gene Markers in Aflatoxin-Resistant Maize Lines Developed Through the IITA-USDA-SRRC COLLABORATION
Food and Feed Safety Research
2013 Annual Report
1a.Objectives (from AD-416):
1. Use the kernel screening assay (KSA) to screen seed of best segregating materials from International Institute of Tropical Agriculture (IITA) for aflatoxin-resistance, and to identify closely-related lines.
2. Conduct field trials of the six TZAR inbreds (as inbreds and hybrids) already developed and released by the IITA-Southern Regional Research Center (SRRC) collaborative project.
3. Conduct proteome analysis on the six TZAR inbred lines to identify resistance-associated proteins (RAPs)/potential markers.
1b.Approach (from AD-416):
Use kernel screening assay (KSA) to screen International Institute of Tropical Agriculture (IITA) bred materials for aflatoxin accumulation to assist in their advancement through the collaborative breeding program. Conduct resistance field trials in southern U.S. to evaluate inbreds released through the program. Use 2 D gel electrophoresis to identify resistance-associated proteins (RAPs) in IITA-Southern Regional Research Center (SRRC) lines to discover potential gene markers. Once identified, characterize RAPs biochemically and physiologically using state-of-the-art techniques to further determine their potential as markers.
Field experiments to evaluate aflatoxin resistance of TZAR inbred lines (progeny of cross of closely related parents or from forced self-pollination) as single cross hybrids (offspring of sexual cross) were conducted over the past season at Mississippi State University, MS in collaboration with the ARS Corn Host Plant Resistance Research Unit at that location. Single cross hybrids of five of the six lines had been made by ARS-GEM (Germplasm Enhancement of Maize Project) at Raleigh, NC and had been previously tested at Lubbock and College Station, Texas, and at ARS-Mississippi State (MSU), MS. Single cross hybrids of these lines were developed using stiff stalk (LH132) or non-stiff stalk (LH51) phenotypes (composite of the plant's observable characteristics or traits) in the cross. LH51 (NSS) and LH132 (SS) are adapted to the Raleigh area. Results of the Mississippi State trial were similar to previous trials at this location and the two Texas locations and were very encouraging. TZAR lines demonstrated resistance to aflatoxin accumulation, especially TZAR 103 and TZAR 106. Yields observed in these two lines also were among the highest of the 41 lines tested in this trial at Mississippi State. Further testing will be conducted after new single cross hybrids are developed this year using tester lines that are locally adapted to the Mississippi and Louisiana regions. Comparative proteomics (comparison of the total protein complement) of the TZAR lines and is being planned and will be conducted with collaboration from an Louisiana State University (LSU), Baton Rouge, LA, Plant Pathologist and an LSU graduate student in that department.