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Poster: Biology & Disease Mgmt: Postharvest Pathology & Mycotoxins


Influence of corn GMO traits for insect control on aflatoxin and fumonisin contamination in Texas
T. ISAKEIT (1), T. Isakeit (1), S. Murray (2), J. Pekar (2) (1) Texas A&M University, U.S.A.; (2) Texas A&M University, U.S.A.

Contamination of corn with aflatoxin and fumonisin is a chronic problem throughout most of Texas. Insect damage to ears can be a predisposition factor, so controlling insects using GMO traits could be a management tool. The objective of our field experiments was to evaluate the impact of three different GMO traits in one parent hybrid (N78S) on mycotoxin contamination. Hybrids were planted in two-row, 22 ft-long plots in a randomized, complete block design near College Station in 2014 and 2015 and were inoculated with either Aspergillus flavus or Fusarium verticillioides or both. Overall, in 2014, the Viptera-trait hybrid expressing Cry1Ab and Vip3Aa20 Bt proteins accumulated less aflatoxin (28 parts per billion (ppb) average, range 1-84 ppb) than hybrids that expressed only Cry1Ab (161 ppb, range 38-340 ppb), or no Bt proteins (175 ppb, range 54-410 ppb). Fumonisin was significantly (P=0.05) reduced in the Viptera-trait hybrid (0.3 parts per million, ppm) compared with the other hybrids (5.5 ppm and 7.5 ppm). In 2015, there was greater drought stress at flowering, which increased overall aflatoxin levels. The Viptera hybrid had the lowest average aflatoxin, 147 ppb, compared with the other hybrids (346 ppb and 274 ppb). The average fumonisin was 3 ppm with the Viptera hybrid, compared with the other hybrids (9.5 ppm and 12 ppm). These results show that in some years, the insect-control traits in some GMO hybrids will not be sufficient to reduce aflatoxin.