ARS | Publication request: Assessing Germplasm Enhancement of Maize (Gem) Project Germplasm As a Source of Resistance to Aflatoxin Accumulation in Grain

Submitted to: Meeting Abstract
Publication Type: Abstract
Publication Acceptance Date: October 25, 2004
Publication Date: October 25, 2004
Citation: Clements, M.J., Windham, G.L., Williams, W.P., Maragos, C.M., Blanco, M.H., Goodman, M.M. 2004. Assessing germplasm enhancement of maize (GEM) project germplasm as a source of resistance to aflatoxin accumulation in grain [abstract]. Proceedings of the 4th Fungal Genomics, 5th Fumonisin Elimination and 17th Aflatoxin Elimination Workshop. p. 2004.

Technical Abstract: Although publicly available corn (Zea mays L.) inbreds with superior resistance to aflatoxin accumulation have been identified, agronomic performance of these sources as inbred lines per se and in hybrid combination is generally poor. Breeding populations and inbred lines per se developed through the USDA Germplasm Enhancement of Maize (GEM) project are derived from crosses of temperate and tropical or subtropical germplasm with the goal of widening the germplasm base of commercial hybrid corn in the U.S. Lines available to GEM cooperators and/ or released to the public through GEM have been selected for agronomic performance; however, they have typically not been evaluated for resistance to aflatoxin accumulation in grain. The objective of this study is to assess GEM breeding crosses and GEM lines for resistance to aflatoxin accumulation in grain, and for agronomics that are suitable for hybrid corn production in the southern U.S. All experiments were planted in replicated, inoculated trials at Mississippi State University in 2003 and 2004. Aflatoxin concentration in grain among 87 GEM lines and experimental checks ranged from 9 to 2147 ng g-1 in 2003. Aflatoxin concentration was lowest from the resistant check, inbred Mp313E. Aflatoxin concentration in grain from four GEM lines (02GEM00281, 02GEM00276, 02GEM00277, and 02GEM00279) did not differ significantly (P>0.05) from Mp313E. All four of these lines had moderate maturity for the southern U.S., and severity of Aspergillus ear rot that did not differ significantly (P>0.05) from Mp313E in 2003 and 2004. Aflatoxin concentration in grain among 19 GEM breeding crosses and experimental checks ranged from 38 to 1087 ng g-1 in 2003. Aflatoxin concentration was lowest from the resistant check, hybrid Mp313E x Mo18W. Aflatoxin concentration in grain from five breeding crosses (01GEM80064, 01GEM80058, 98GEM80076, 01GEM80062, and 95GEM80061) did not differ significantly (P>0.05) from Mp313E x Mo18W. All five of these breeding crosses had severity of Aspergillus ear rot that did not differ significantly (P>0.05) from Mp313E in 2003 and 2004. All five of these breeding crosses have moderate maturity for the Southern U.S. GEM lines in this study will be evaluated for agronomic characteristics and resistance to aflatoxin accumulation in grain as testcrosses developed with commercial inbreds Holden's LH195 and LH210 in 2005. All GEM lines also are being evaluated for resistance to leaf feeding by southwestern corn borer (Diatraea grandiosella Dyar). Ear to row and recurrent selection programs are currently underway with several of the most promising lines and breeding crosses.