Changes in growth and quality of three mint cultivars at different harvesting periods

This study was conducted to investigate the growth and quality of three mint cultivars. Eau de cologne mint showed the best growth in terms of plant height, number of leaves, and fresh weight. Among quality traits, the chlorophyll content was highest in eau de cologne mint, whereas the vitamin C content was highest in pineapple mint. The nitrate, phosphate, and essential oil contents were higher in eau de cologne mint but the contents of the major essential oil constituents, L-limonene and L-menthone, were higher in apple and pineapple mint. The total yields of all three cultivars gradually increased with increasing harvesting period. The essential oil contents of eau de cologne and pineapple mint increased with increasing harvesting period, but that of apple mint decreased. The menthol contents of essential oil increased in apple and pineapple mint at each harvesting period, and 135 days after transplanting, major changes in oil constituents were detected in apple mint. Eau de cologne mint exhibited the best growth, whereas apple mint, with only slightly poorer growth, had better essential oil constituents.