Effect of harvesting time on change in oil quality of Mentha piperita L. Chemotypes

Evaluation for essential oil composition and to assess the change in quality of essential oil with age, harvesting time and maturation phase M. piperita clones namely MP-1 to MP12 were taken under study. It was found that nine cultivars with basic chromosome number 2n=72, were best suited under fluctuating environments with respect to oil content and quality as well with more than 70% menthol content.