|WILLCOX, MARTHA - International Maize & Wheat Improvement Center (CIMMYT)|
|DAVIS, GEORGIA - University Of Missouri|
|BETRAN, JAVIER - Syngenta|
|Holland, Jim - Jim|
Submitted to: Molecular Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/26/2012
Publication Date: 4/9/2013
Citation: Willcox, M., Davis, G., Warburton, M.L., Windham, G.L., Abbas, H.K., Betran, J., Holland, J.B., Williams, W.P. 2013. Confirming quantitative trait loci for aflatoxin resistance from Mp313E in different genetic backgrounds. Molecular Breeding. 32(1):15-26.
Interpretive Summary: The fungus Aspergillus flavus (Link:Fr) causes ear rot of maize (Zea mays L.) and produces aflatoxin, which is toxic to humans and animals. Reducing aflatoxin in maize can be done via plant breeding, and the identification of genes that give resistance to maize against the fungus. These genes are identified by genetic mapping, and they can then be used to improve susceptible maize lines. We must first test that the genes from one resistant maize lines will behave in the same way in a new maize line and provide the same levels of resistance to all maize they are crossed into, and in all environments that the maize lines are grown in. This study is an attempt to find if the same genes or chromosomal regions from a resistant maize line, Mp313E, that gave resistance against the fungus when crossed with one susceptible maize line (B73) gives resistance when crossed with another susceptible maize line (Va35). Many of the same genes and regions were identified, as well as some new ones. We also tested the lines with these genes or regions in many environments, and found that some behave the same, but some do not, when grown in very different environments. These results will help guide future breeding efforts with Mp313E in making resistant maize inbred lines.
Technical Abstract: The fungus Aspergillus flavus (Link:Fr) causes ear rot of maize (Zea mays L.) and produces the toxic metabolic product aflatoxin. One particularly effective method to control the fungus is via host plant resistance, but while several resistant breeding lines have been identified, transferring the resistance genes from these lines into elite cultivars has been less effective than needed. A high number of genes involved with resistance, each with a small effect, and some only found under certain environmental conditions, has hampered resistance breeding. The identification of markers linked to genomic regions associated with resistance would aid in this effort. The goals of this study were to identify and characterize Quantitative Trait Loci (QTL) conferring resistance to aflatoxin accumulation from resistant maize donor Mp313E in a background of the susceptible inbred line Va35 and compare them to the QTL identified from Mp313E in a background of B73; and to test the stability of the QTL identified in Mp313E x Va35 in multiple environments by remapping the phenotypic tails of the Mp313E x Va35 mapping population in new locations. Sixteen different QTL were found in this study, 11 of which were also found in different environments using the phenotypic tail subset mapping population, and 5 of which were also reported in the Mp313E x B73 mapping population. This indicates that many of the QTL are stable over the environments and genetic backgrounds tested, which will make them more valuable in breeding efforts