To increase the selection efficiency for new cultivars in cut roses during breeding programs, phenotypes of seedlings in two cross combinations, C1 (Rosa hybrida ‘Yellow King’ x ‘Aladin’) and C2 (R. hybrida ‘Evelien’ x ‘Sunny Isle’), were investigated. Although most seedlings showed classic-type flower shapes, some (0.4% - 0.7%) had tomato-shaped flowers, especially at the young plant stage (6 months old). The variation in petal color was high, and pink and pink-mixed flowers were dominant, accounting for 72% in C1 and 76% in C2 at the mature plant stage (13-month-old plants). However, the seedlings had changes in the expression of petal color at different growth stages. The number of petals at the young plant stage had a strong positive correlation with those at the mature plant stage in C1 (r = 0.84***) and C2 (r = 0.73***). Sizes of flowers and petals increased with the growth of the seedlings, and their traits at the young plant stage had positive correlations with those at the mature plant stage in both C1 (r = 0.32***) and C2 (r = 0.39***). Prickle expression on stems was mostly in level 5 at the young plant stage and then dispersed to various classes at the mature plant stage, which increased the variation and coefficient of variation. To select seedlings for new cultivars through breeding processes, breeders should consider the growth stage for targeted traits.

Abstract
Introduction
Materials and Methods
    Plant materials
    Flower characteristics
    Statistical analysis
Results and Discussion
    Phenotypic variation of seedlings in cut roses
    Correlation for flowering traits between youngand mature seedlings in cut roses
References

• Je Yeon Yeon(Natural Science Research Institute, University of Seoul)
• Min Ji Kim(Department of Environmental Horticulture, University of Seoul)
• Yeong Chan Shin(Department of Environmental Horticulture, University of Seoul)
• Gyeong Rok Yang(Floriculture Research Division, National Institute of Horticultural and Herbal Science)
• Wan Soon Kim(Natural Science Research Institute, University of Seoul/Department of Environmental Horticulture, University of Seoul) Corresponding author