Biorational Preservation of Rose (Rosa hybrida L.) Cut-Flower Using Stevia (Stevia rebaudiana B.) and Thyme (Thymus vulgaris L.) Extracts

Rose cut flower is one of the widely grown cut flowers in Kenya. However, most roses have a challenge of short vase life. This study aimed at determining the efficacy of plant extracts from thyme and stevia in preservation of rose cut-flowers. Two rose cut-flower cultivars; ‘radiance and ‘high & sparkling’ were subjected to stevia and thyme extracts each at three levels (0.2, 0.4, and 0.6gL-1). Thyme extracts at a concentration of 0.2 gL-1 significantly (p≤001) extended the vase life of rose cut flower by 3.5 days and floral absorption rates by 10.4% compared to the commercial preservative (chrysal) at the same concentration rates. Application of higher doses (0.4gL-1 and 0.6gL-1) of plant extracts led to shorter vase life (6 days) of rose cut flower and maximum bent neck records at day 8. The response of rose cut flower to the treatments did not vary between cultivars. The results from this study indicate that thyme extracts offer an attractive alternative to the use of chemical floral preservatives for prolonging the vase life and enhancing quality of rose cut flower. The efficacy of extracts is however depended on the concentration level with 0.2gL-1 dosage recording the best results.