Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/13/2003
Publication Date: 10/13/2003
Citation: Brooks, T.D., Williams, W.P., Windham, G.L., Abbas, H.K. 2003. Molecular characterization of resistance to aflatoxin accumulation in Mp313E [abstract]. 16th Annual Aflatoxin Elimination Workshop Proceedings. p. 51.
Technical Abstract: Aflatoxin is a carcinogenic and toxic compound produced by the fungus Aspergillus flavus that can be found at detrimentally high concentrations in maize grain. Screening procedures have led to the discovery of sources of resistance to aflatoxin accumulation in maize, but poor associated agronomic characteristics and complex inheritance have limited transfer of resistance to elite inbreds. This study was undertaken to identify quantitative trait loci (QTL) associated with reduced aflatoxin accumulation and aid in transfer of regions containing them. 210 F2:3 families derived from a cross between the resistant inbred Mp313E and the susceptible inbred B73 were evaluated in replicated trials in four environments for resistance to aflatoxin accumulation. Families were also genotyped using simple sequence repeat (SSR) markers to develop a genetic map for QTL analysis. Composite interval mapping (CIM) was used to identify 3, 2, 5, and 3 QTL regions within the tests MSU2000, Stone2000, MSU2001, and MSU2002, respectively. QTL tended to be additive in nature with the Mp313E parent contributing to reduced aflatoxin concentration in all but one case. Two QTL regions were significant in at least three environments. QTL-3, represented by marker bnlg371, was located on chromosome two and accounted for 7% to 18% of variation in aflatoxin levels depending on environment. QTL-5, represented by marker bnlg2291, was located on chromosome four with explained variance ranging from 8% to 16%. This QTL has been noted in earlier studies while QTL-3 is new. Identified QTL confirm important regions influencing aflatoxin accumulation previously identified and present new ones of equal effect.