Location: Corn Host Plant Resistance Research2013 Annual Report
1a. Objectives (from AD-416):
The objectives of this proposal are: (1) to evaluate aflatoxin, yield, and agronomic traits of the new high yielding TAES experimental hybrids for a second year; (2) to conduct large scale strip tests of S2B73BC x BC300 and S1W x CML343 for yield, aflatoxin level, and agronomic traits in TX; (3) to develop and advance new lines toward producing low-aflatoxin corn hybrids; and (4) to participate in SERAT tests. The results from this research will help the seed industry to commercialize the new germplasm and lead to the release of new inbred lines and hybrids with multiple stress tolerance and adaptation to Texas and southern states.
1b. Approach (from AD-416):
Corn hybrids developed by Texas Agricultural Experiment Station and other widely grown hybrids will be grown at locations in Texas and Mississippi under different degrees of drought stress. At some locations the hybrids will be inoculated with Aspergillus flavus. Data will be recorded on flowering date, plant height, lodging, and other agronomic traits. Mature ears will be hand harvested and rated for ear mold and insect damage. Grain will be analyzed for aflatoxin contamination. The proposed research will help to identify multiple stress resistant corn and provide the germplasm and information needed by the seed industry to develop and commercialize hybrids with resistance to aflatoxin contamination.
3. Progress Report:
Aflatoxin contamination of corn by Aspergillus flavus is a chronic problem in the southern United States where a hot and dry environment stresses plants and increases aflatoxin production. Aflatoxin is particularly serious in drought-susceptible hybrids grown under dry and hot environments. Ear damage by corn earworm also increases aflatoxin accumulation. Producers need new corn hybrids that are adapted to the southern United States and resistant to aflatoxin contamination. The objectives of this study were to develop multiple-stress tolerant corn inbred lines and hybrids to reduce aflatoxin contamination and to produce near-isogenic lines (NILs) for validating aflatoxin resistance quantitative trait loci (QTL). One hundred twenty experimental corn hybrids were evaluated for yield and aflatoxin contamination in several locations in Texas (Dumas, Halfway, Lubbock, College Station, Corpus Christi, Uvalde, and Weslaco) and one location in Mississippi. These hybrids were produced from crosses among Mp715 derived lines, lines derived from a crosses between corn and teosinte, and other advanced lines developed at Texas A&M AgriLife Research Center in Lubbock, Texas. The Mp715 derived lines were developed from breeding crosses involving Mp715, a line with resistance to aflatoxin contamination developed by ARS scientists in the Crop Science Research Laboratory at Mississippi State, Mississippi. Hybrids were entered into the Southeastern Regional Aflatoxin Test (SERAT). The hybrids were evaluated for resistance to aflatoxin contamination, corn earworm damage, and yield at several locations across the southern United States. Results from these tests have shown that several experimental hybrids developed at the Texas A&M AgriLife Research Center not only yielded well but also had significantly lower levels of aflatoxin accumulation than the commercial check hybrids. These lines with tolerance to multiple stresses are ready for public release. Research efforts on reducing pre-harvest aflatoxin contamination were presented at a field day attended by breeders with seed companies. Several lines that have low levels of aflatoxin accumulation and excellent agronomic characteristics are being prepared for release. One of the inbred lines has been licensed to a seed company and is now used as a parental line of a commercial hybrid. This hybrid is currently widely grown in the southern United States. The hybrid produces high grain yield, has excellent grain quality, and low levels of aflatoxin contamination. Additional hybrids made with this line will be launched in the near future.