ABSTRACT
This chapter focuses on the study of the genetic basis of phenomena such as heterosis and genotype by environment interaction, and on the use of marker technology for enhancing plant breeding efficiency. During the 1970s and early 1980s, several pioneering studies were conducted in maize that focused on associating marker genotypes with quantitative trait performances. Heterosis has been a major contributor to the success of the commercial maize industry and is often an important component of the breeding strategies of many crop and horticultural plants. Although there is little evidence for quantitative trait locus (QTL) by environment interaction in most investigations of traits such as grain yield in maize, these studies usually have been conducted under near optimum growing conditions. Molecular-marker technology has been demonstrated to be effective for identifying and mapping QTLs in maize, as well as in many other plant species, and for studying phenomena such as heterosis and genotype by environment interaction.
