IMPROVED METHOD OF CALCULATING THE ORNAMENTAL VALUE OF FLOWERS BASED ON PETAL DISCOLOURING MEASURED IN CIEDE2000
A method to quantify the ornamental value (OV) of a flower of garden rose (Rosa ×hybrida) was created, based strictly on measurements. Here OV means the capacity to produce a uniform colour effect. The blooming time of flowers was distributed into 23 phenological sub-stages from the immature bud to the falling of petals. CIEDE2000 standard chromatic differences (ΔE00) were calculated between the petal colours of each stage and stage 6 the optimal state of the flower. The ornamental value of a colour is OVc=15-ΔE00. The OV of a stage is OV=Av%×OVc, where Av% is the relative visible surface of the flower as a percentage of the surface of stage 6. The total OV of a section of stages is OVt=Σ(Av%×(15-ΔE00)×ls), where ls is the length of each stage measured in days. The OVt should be calculated for three different sections of subsequent flowering stages: a) the whole life of the flower (2-9 stages), b) the life of the flower before dead-heading (2-7.5 stages), and c) the middle (5.5-7) stages. In 2012, the method was further improved by the interpolation of the colour parameters at the non-measured stages. This new method is presented with an example of 10 red floribunda and polyantha rose cultivars. According to the OVt scores, 9 of the examined 10 cultivars are highly attractive to stage 7.5, but two of them have low ornamental value if the whole life of the flower is taken into consideration. According to the scores, these two cultivars need deadheading while the others dont need this process. According to the results, this OV calculation gives objective results, and is also suitable for determining the extent of maintenance the cultivars require.
Boronkay, G. (2015). IMPROVED METHOD OF CALCULATING THE ORNAMENTAL VALUE OF FLOWERS BASED ON PETAL DISCOLOURING MEASURED IN CIEDE2000. Acta Hortic. 1064, 205-210
Rosa, rose, chromatic difference, floribunda, polyantha, CIE Lab, CIE LCh