A marker closely linked to the gene of interest for an agronomic trait will be used for
The principle of metabolic engineering and inheritance explains that exogenous gene introduction and pathway extension enable trait improvement. Hence foreground selection fits best because it demonstrates metabolic extension and combinatorial biosynthesis, as documented in authoritative sources on genetics and biotechnology.
Ref: Pierce, Genetics: A Conceptual Approach, 6th Edition, Chapter 3, discusses genotype-phenotype correlation and inheritance patterns providing framework for genetic transmission and metabolic engineering.