Location: Corn Host Plant Resistance Research2011 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
For the second year, 300 testcrosses produced by crossing a diverse group of germplasm lines with Va35 were evaluated for aflatoxin accumulation, corn earworm damage, and days to mid-silk. This work was conducted in cooperation with ARS at Mississippi State (6406-21000-011-00D) and a cooperator at Texas A&M University (6406-21000-011-10S). Grain samples from all locations and both years were analyzed for aflatoxin concentration at Mississippi State: some germplasm lines appear to be potentially useful sources of resistance to aflatoxin contamination. After genotyping by high throughput sequencing is completed and the results are analyzed, new genes or groups of genes associated with resistance to aflatoxin contamination should be identified. Experimental hybrids were developed from a breeding cross containing Mp715, which is a known source of resistance developed and released by ARS at Mississippi State (6406-21000-011-00D). Aflatoxin concentration was significantly different among the hybrids. The low-aflatoxin hybrids also produced grain yields comparable to the commercial checks across test locations. Evaluations continue to determine which of the newly developed lines will be released as sources of resistance to aflatoxin contamination. One study involving 35 experimental hybrids of Mp715-derived lines was conducted for a second year in Lubbock and Corpus Christi in Texas and Mississippi State, Mississippi, in 2010. Another study involving 50 crosses of teosinte-derived lines was conducted in four locations in Texas and in Mississippi State, Mississippi, in 2011. The goal is to identify low-aflatoxin corn inbred lines with good agronomic traits. Backcross populations are being developed from crosses between resistant lines, Mp313E, Mp715, Mp717, and susceptible lines, PHW65 and PHW79. These populations will be used to confirm quantitative trait loci (QTL) associated with resistance to aflatoxin accumulation. Activities were monitored through a meeting of cooperating scientists at a workshop on diseases of corn, conference calls, e-mails, written reports, and phone calls.