Evaluation of elite maize inbred lines for reduced Aspergillus flavus infection, aflatoxin accumulation, and agronomic traits

Authors: PEKAR, JACOB - Texas A&M University; MURRAY, SETH - Texas A&M University; ISAKEIT, THOMAS - Texas A&M University; Scully, Brian; Guo, Baozhu; Knoll, Joseph - Joe; Ni, Xinzhi; Abbas, Hamed; WILLIAMS, WILLIAM - Mississippi State University; XU, WENWEI - Texas Tech University

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2019
Publication Date: 10/3/2019
Citation: Pekar, J.J., Murray, S.C., Isakeit, T.S., Scully, B.T., Guo, B., Knoll, J.E., Ni, X., Abbas, H.K., Williams, W.P., Xu, W. 2019. Evaluation of elite maize inbred lines for reduced Aspergillus flavus infection, aflatoxin accumulation, and agronomic traits. Crop Science. 59:2562-2571. https://doi.org/10.2135/cropsci2019.04.0206.
DOI: https://doi.org/10.2135/cropsci2019.04.0206

Interpretive Summary: Aflatoxin is a harmful carcinogenic mycotoxin produced by fungus called Aspergillus flavus, which limits the marketability of corn and lowers the economic value for producers. Despite a number of public breeding efforts, no genotypes have yet been identified that are completely resistant to aflatoxin, only quantitative reductions have been found. Public material bred for decreased susceptibility to aflatoxin in the United States includes a most viable testing program in the U.S. called the Southeast Regional Aflatoxin Trials (SERAT), which has tested 30-40 public breeding sector hybrids for agronomics and aflatoxin accumulation each year since 2003. The SERAT trials have shown that the best public hybrids are more tolerant than current commercial hybrids available to producers; however many, but not all, public hybrids lack the favorable agronomics and realized yield that producers demand. Here we sought to screen a diverse set of released public lines, along with important expired plant variety protection (ex-PVP) commercial lines for both aflatoxin and yield in Texas environments. Many of the released and to-be-released public breeding lines for aflatoxin resistance and all ex-PVP lines have not previously been screened in a common environment. A total of nine environments, beginning in 2012, were used to screen inbred lines for aflatoxin accumulation and yield in the stressful climate of Texas. There were several inbred lines evaluated in this study with potential utility in future studies, such as breeding for resistance and hybrid development for genetically improved resistance.

Technical Abstract: Mycotoxins, produced by the fungus Aspergillus flavus, are harmful to humans and animals and result in large economic losses. Developing and disseminating resistant germplasm is a critical component to reduce or eliminate the accumulation of pre-harvest aflatoxins in maize (Zea mays L.). To combat this global issue, new and historic germplasm were evaluated for use in breeding and the development of hybrid varieties that can be utilized by producers. Ninety-three different inbred lines were evaluated for agronomic traits during the years of 2012 to 2016 in two locations (nine environments) by inoculation with A. flavus. Several inbred lines had lower levels of aflatoxin but had higher yields than the checks. The top seven best inbred lines on average had a back-transformed aflatoxin value of 14.1 ng g-1 and an average yield of 3.2 T/ha-1 while the checks had 185.9 ng g-1 and 2.5 T/ha-1, respectfully. There were several inbred lines evaluated in this study with potential utility in future studies, such as breeding for resistance, segregation population creation, and hybrid development for genetically improved resistance.