Flower fragrance manifests as a specific scent resulting from the synthesis of volatile essential oils. This trait plays a functional role in attracting insect pollinators and serves as an important factor of a variety's ornamental value, determining its consumer appeal in floriculture.
Fragrance intensity is assessed during variety trials using an organoleptic method involving intensity scales or scoring systems, as there are no universally accepted physical or chemical units of measurement. The evaluation takes into account both the presence of the scent and its qualitative characteristics within the scope of the plant's overall ornamental quality.
The expression of the trait depends on environmental conditions, including light intensity, water balance, and soil nutrient availability. The level of aromatic compounds varies depending on the bud development stage and the time of day, and can also be suppressed by agronomic factors, such as excessive nitrogen fertilization.
Genetically, fragrance is a complex trait determined by a set of genes, which often competes with other qualities, such as flower shape or resistance. Breeding may be directed toward prioritizing external parameters; therefore, the degree of fragrance expression is not always a stable characteristic.