Quantitative Trait Loci Mapping of Heavy Metal Accumulation and Resistance in Crop Plants

Abstract

Industrial revolution and anthropogenic activities have enhanced the spread of many heavy metals to different environmental sites from the earths’ crust. Environmental pollution caused by toxic heavy metals is a major threat to human health. There are different sources by which plants get exposure to heavy metals, such as fertilizer and pesticides application in fields, mining industries and groundwater. Heavy metals induce damages in plants at physiological, biochemical and molecular level, either directly or indirectly by generation of reactive oxygen species or free radicals. In order to reduce the toxicity of the these heavy metals in plants different strategies can be used, either by application of specific fertilizer, selection of heavy metals tolerant plants or through genetic engineering. Analyzing the genetic and molecular mechanisms that are involved in heavy metals tolerance is expected to enhance the development of heavy metals tolerant plants, and mapping of quantitative trait locus (QTL) associated with their accumulation and resistance is helpful to improve the heavy metal resistance in plants. A QTL that is responsible for controlling heavy metals resistance in plants can be used for marker-assisted selection in selecting low heavy metal content plants or tolerant plants in a breeding program. In this chapter, we focus on mapping QTL for the selection of agronomic traits for improving the heavy metals resistance in breeding program.