Quantitative Trait Loci Contributing Resistance to Aflatoxin Accumulation in the Maize Inbred Mp313E

Aflatoxin is a carcinogenic and toxic compound produced by the fungus Aspergillus flavus (Link:fr) that can be found at detrimentally high concentrations in maize (Zea mays L.) grain. Screening has led to the discovery of sources of resistance to aflatoxin accumulation in maize, but associated poor agronomic characteristics and complex inheritance have limited transfer of resistance to elite inbreds. A set of 210 F 2:3 families derived from a cross between inbred lines Mp313E (resistant) and B73 (susceptible) was 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 quantitative trait loci (QTL) analysis. Composite interval mapping (CIM) was used to identify 2, 3, 5, and 3 QTL within the tests at Stoneville (2000) and Mississippi State (2000, 2001, 2002), respectively. The QTL were primarily additive in nature, with Mp313E contributing to reduced aflatoxin concentration in all but one case. Two QTL regions were significant in at least three environments. The afl3 locus, represented by marker bnlg371, was located on chromosome two and accounted for 7 to 18% of variation in aflatoxin levels depending on environment. The afl5 locus, represented by marker bnlg2291, was located on chromosome four, with explained variance ranging from 8 to 18%. This QTL has been noted in earlier studies whereas afl3 is new. Identified QTL confirm important regions influencing aflatoxin accumulation previously identified and present new ones of equal effect.

[1]  Z. Zeng.  Precision mapping of quantitative trait loci. , 1994, Genetics.

[2]  G. Payne,et al.  Aflatoxin in maize , 1992 .

[3]  G. E. Scott,et al.  Evaluation of field inoculation techniques for screening maize genotypes against kernel infection by Aspergillus flavus in Mississippi. , 1989 .

[4]  R. Doerge,et al.  Permutation tests for multiple loci affecting a quantitative character. , 1996, Genetics.

[5]  G. E. Scott,et al.  Registration of Mp420 Germplasm Line of Maize , 1992 .

[6]  J. Hanway,et al.  How a corn plant develops [Iowa] , 1982 .

[7]  K. W. Campbell,et al.  Evaluation of corn genotypes for resistance to Aspergillus ear rot, kernel infection, and aflatoxin production , 1995 .

[8]  A. Hallauer,et al.  Quantitative Genetics in Maize Breeding , 1981 .

[9]  P. Cregan,et al.  A Low-Cost, High-Throughput Polyacrylamide Gel Electrophoresis System for Genotyping with Microsatellite DNA Markers , 2003 .

[10]  G. E. Scott,et al.  Registration of Mp313E Parental Line of Maize , 1990 .

[11]  W. Williams,et al.  Inoculation Techniques Used to Quantify Aflatoxin Resistance in Corn , 2003 .

[12]  R. Jorgensen,et al.  Ribosomal DNA spacer-length polymorphisms in barley: mendelian inheritance, chromosomal location, and population dynamics. , 1984, Proceedings of the National Academy of Sciences of the United States of America.

[13]  W. Williams,et al.  Registration of Maize Germplasm Line Mp715 , 2001 .

[14]  Bruce S. Weir,et al.  Constructing Genetic Maps by Rapid Chain Delineation , 1994 .

[15]  G. E. Scott,et al.  Sources of Resistance in Maize to Kernel Infection by Aspergillus flavus in the Field , 1988 .

[16]  T. Rocheford,et al.  Quantitative trait loci for low aflatoxin production in two related maize populations , 2003, Theoretical and Applied Genetics.

[17]  Douglas L. Park,et al.  Perspectives on aflatoxin control for human food and animal feed , 1993 .

[18]  M. Castegnaro,et al.  Carcinogenic risk assessment of mycotoxins , 1998 .

[19]  W. Shier,et al.  Aflatoxin and fumonisin contamination of commercial corn (Zea mays) hybrids in Mississippi. , 2002, Journal of agricultural and food chemistry.

[20]  R. Doerge,et al.  Significance thresholds for QTL interval mapping tests , 1996, Heredity.

[21]  J. Irwin,et al.  Independent Inheritance of Genes Conditioning Resistance to Phytophthora Root Rot from Diploid and Tetraploid Alfalfa 1 , 1987 .

[22]  W. Williams,et al.  Aspergillus flavus Infection and Aflatoxin Accumulation in Resistant and Susceptible Maize Hybrids. , 1998, Plant disease.