INFLUENCE OF HARVEST INDEX ON THE VASE LIFE OF FIVE Rosa hybrida CULTIVARS

Abstract

One of the main problems in marketing of cut flowers is the lack of floral opening because the appropriate state of maturity for harvesting is unknown. The objective of this study was to determine the optimal harvest index in order to enhance the opening and vase life of floral stems of seven Rosa hybrida cultivars kept in water or Chrystal Clear® solution. Sixteen floral stems were harvested with three harvest indexes for their analysis in the laboratory, and they were separated into two groups; one was placed in tap water (T1) and another in Chrystal Clear® solution (T2). The experimental unit was two floral stems placed in a vase with 270 mL of water or solution. The vases were distributed randomly in a room with illumination of 10 umol m^-2 s^-11, photoperiod of 12 h and temperature of 23±3 °C. The stems were cut on the fourth day, the water in group T1 was changed, and group T2 was kept without changing the solution. The initial and final diameter of the flower was evaluated, as well as the water absorption rate, live weight and vase life. The stems of cv. Polar Star presented the greatest floral opening, and the buds of ‘Samurai’ and ‘Freedom’ had the smallest opening. The ‘Engagement’ and ‘Topaz’ stems in the three harvest indexes presented floral opening above 70 %. The other cultivars should be harvested with an index of at least two. ‘Polar Star’ had the longest vase life (12.4 d) and the shortest was found in ‘Freedom’ and ‘Samurai’ (7.3 d). The Chrystal Clear® solution did not modify the floral opening; however, it did increase the fresh weight, vase life and improved the appearance. The harvest index to obtain the higher fresh weight and better performance in vase life is index two.