Nuclear and other genomes
Most of the genetic material in eukaryotes is located in the nucleus. The mitochondria and/or chloroplast organelles also contain DNA, but only a small number of genes. These genes are inherited maternally.
Therefore, unless specified, genetic and genomic studies refer to the nuclear genome.
Image from Michael Davidson, Florida State University, http://micro.magnet.fsu.edu/cells/plantcell.html