|JI, XIANGYUN - University Of Georgia|
|FOUNTAIN, JAKE - University Of Georgia|
|LI, HONG - Shanxi University|
|LEE, DEWEY - University Of Georgia|
Submitted to: The Crop Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/2/2016
Publication Date: 11/25/2016
Citation: Guo, B., Ji, X., Ni, X., Fountain, J.C., Li, H., Abbas, H.K., Lee, D., Scully, B.T. 2017. Evaluation of maize inbred lines for resistance to pre-harvest aflatoxin and fumonisin contamination in the field. The Crop Journal. 5:259-264. doi:10.1016/j.cj.2016.10.005.
Interpretive Summary: The contamination of agricultural crops with aflatoxin and fumonisin is a major concern for global food security particularly in developing countries. Breeding for resistance is still considered to be one of the best strategies currently available to lower aflatoxin and fumonisin accumulation in maize. In these experiments, we screened 87 inbred lines for resistance to aflatoxin and fumonisin contamination using a field screening assay for two years. There were 53 inbred lines that had lower levels of aflatoxin accumulation than the resistant control, Mp717. The inbred lines TUN15, TUN61, TUN37, CY2 and TUN49 had the lowest aflatoxin accumulation, and CN1, GT601, TUN09, TUN61 and MP717 were found to have the lowest fumonisin accumulation. TUN61 exhibited the lowest accumulation of both mycotoxins, which has been used in breeding program. Also, this research indicated that high levels of aflatoxin could coexist with high levels of fumonisin in maize, and there was an overall positive correlation coefficient of 0.37. By identifying resistant maize germplasm to both aflatoxin and fumonisin contamination, it would be possible to enhance the resistance of corn hybrids in breeding programs to reduce the contamination of aflatoxin and fumonisin, and allow for further study of the specific mechanisms underlying resistance to both A. flavus and Fusarium spp.
Technical Abstract: Two important mycotoxins, aflatoxin and fumonisin, are among the most potent naturally occurring carcinogens, contaminating maize (Zea mays L.) and affecting the crop yield and quality. Resistance of maize to pre-harvest mycotoxin contamination, specifically aflatoxin produced by Aspergillus flavus and fumonisin produced by Fusarium verticillioides, two globally important mycotoxins, is a goal in breeding programs which screen for these important traits in order to develop resistant commercial hybrids. In this study, we conducted a field evaluation of 87 inbred lines, primarily originating from China and Mexico and not previously screened for resistance, in 2007 and 2008. The objectives were to identify resistant germplasm for breeding and to examine the relationship of resistance to both mycotoxins. Aflatoxin and fumonisin were present in samples harvested from all lines in both years. Concentrations of total aflatoxin ranged from 52.00 ± 20.00 to 1524.00 ± 396.00 µg/kg, while fumonisin ranged from 0.60 ± 0.06 to 124.00 ± 19.50 mg/kg. The inbred lines TUN15, TUN61, TUN37, CY2 and TUN49 had the lowest aflatoxin accumulation, and CN1, GT601, TUN09, TUN61 and MP717 were found to have the lowest fumonisin accumulation. TUN61 exhibited the lowest accumulation of both mycotoxins. This study also confirmed previous observations that high levels of aflatoxin can coexist with fumonisin with 55 maize lines showing a positive correlation coefficient between the concentrations of aflatoxin and fumonisin, and 32 lines showing a negative correlation coefficient. These selected lines, particularly TUN61, may provide sources of resistance to mycotoxin contamination in breeding programs. However, the mechanism of resistance among this germplasm remains to be answered. Future research should also address factors that impact the fungus-plant interaction, such as resistance to herbivory and environmental stress tolerance