Which factor does NOT influence chemotypes?

The correct answer is the harvesting method, as it does not directly influence the chemotype of a plant. Chemotypes refer to the different chemical compositions that can occur within a species due to genetic and environmental factors.

Soil, altitude, and climate are critical factors that can affect the plant's growth conditions, which in turn can lead to variations in the plant's secondary metabolites, thus influencing its chemotypes. The soil type can affect nutrient availability, pH, and water retention, all of which can alter the chemical profile of the plant. Altitude can impact temperature and light levels, affecting the growth rate and chemical production within the plant. Climate, through temperature and weather patterns, can also significantly influence the way a plant develops and its resulting chemical composition.

In contrast, the method used for harvesting a plant does not change its genetic makeup or the environmental conditions during growth; it simply refers to when and how the plant is collected. Therefore, it does not have an effect on the plant's chemotype. Understanding these factors is essential for recognizing how various environmental and genetic aspects can create diversity within plant species, particularly in aromatherapy and essential oil production.