Mapping of Quantitative Trait Loci for Resistance to Aflatoxin Accumulation in a Resistant Corn Inbred Line Mp715.

Title: Mapping of quantitative trait loci for resistance to aflatoxin accumulation in a resistant corn inbred line Mp715

Ramesh Dhakal and Prasanta K. Subudhi

School of Plant, Environmental and Soil Sciences, LSU, 207 Sturgis Hall, Baton Rouge

 

Abstract

Aflatoxin contaminated corn is a serious health hazard for both humans and animals. Aflatoxin accumulation in corn continues to be a perpetual problem in all southeastern corn growing states where drought and higher temperature prevails during cropping season. Identification and development of resistant inbred lines is the sustainable way to reduce aflatoxin contamination.. Mapping of quantitative trait loci (QTL) for resistance to aflatoxin accumulation in maize kernels from resistant germplasm and markers associated with them can be helpful to speed up the breeding program. An F_2:3 mapping population developed from the cross between Mp715 and B73 was evaluated in a replicated field experiment in 2012 and 2013. MP 715 is a resistant inbred line where as B73 is susceptible and widely used for developing inbred lines for hybrid development. Genetic linkage map was constructed using 137 simple sequence repeat (SSR) markers covering whole genome. There were five to seven QTLs for aflatoxin resistance identified in both years.  These QTLs were located on chromosomes 3, 4, 5, 8, 9, and 10 with contribution ranging from < 1.0 to 9.2% toward resistance reaction. Highly significant correlation was observed between husk cover and aflatoxin content in both years indicating important role of close husk cover in reducing aflatoxin accumulation. Few major QTLs responsible for close husk cover were identified in both years. Therefore, it should be possible to use molecular markers associated with this trait to develop aflatoxin resistant inbred lines through marker-assisted breeding.