In a group of rose plants, some individuals have light yellow flowers and others have dark yellow flowers. In this group, the gene for the flower color trait has two alleles. The allele for dark yellow flowers (f) is recessive to the allele for light yellow flowers (F).
A certain rose plant from this group has the homozygous genotype ff for the flower color gene.
Based on this information, what is this plant's phenotype for the flower color trait?