Breeding and characteristics of new cultivars ‘Eternity Peach’ and ‘Eternity Shine’ in the dahlia Eternity series with long vase life

Abstract

The vase life of cut ornamental flowers is important breeding target in determining their quality and consumers’ preference. As the vase life of cut dahlia (Dahlia variabilis) flowers is very short, we initiated a research breeding program in 2014 to improve it. We chose 22 commercial cultivars as initial breeding materials, and repeatedly crossed and selected promising offspring with long vase life for three generations, from 2014 to 2018. Third-generation selected line 828-18, which has beautiful gradation flower color with a pink and white center, and line 937-C58 (‘Namahage Cute’ × second-generation selected line 628-48) with deep pink flowers were judged to be the most suitable as new cultivars with long vase life. We registered these cultivars with Japan's Ministry of Agriculture, Forestry and Fisheries and released them as ‘Eternity Peach’ and ‘Eternity Shine’. These two new dahlia cultivars had genetically determined long vase lives of 6.4 to 12.3 days (1.2 to 2.2 times the vase life of a standard cultivar, ‘Kamakura’) in distilled water, 9.1 to 12.1 days (1.4 to 2.0 times the vase life of ‘Kamakura’) in GLA (10 g·L⁻¹ glucose, 0.5 ml·L⁻¹ kathon CG, and 50 mg· L⁻¹ aluminum sulfate) under 23 ℃, 12-h photoperiod, and 70% RH conditions in 2020 and 2021. Moreover, flower of ‘Eternity Shine’ had low sensitivity to ethylene (no petal abscission upon 10 µL·L^-1 ethylene treatment in 2020 test). Cut flowers cultivated at five locations nationwide with different cultivation seasons in 2020 and 2021 also showed similar long vase life, clearly indicating that the long vase life of our three cultivars were not due to the environment but the characteristics of cultivars.