Breeding and characteristics of new dahlia cultivars ‘Eternity Moon’ and ‘Eternity Sunset’ with long vase life

Abstract

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 four generations, from 2014 to 2021. Fourth-generation selected line 909-4, which has white flower color, and third-generation selected line 916-34, whose flower color gradually changes from bright red to apricot color after harvest 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 Moon’ and ‘Eternity Sunset’. These two new dahlia cultivars had genetically determined long vase lives of 8.4 to 12.1 days (1.5 to 2.2 times the vase life of a standard cultivar, ‘Kamakura’) in distilled water, 8.8 to 11.9 days (1.5 to 1.9 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°C, 12-h photoperiod, and 70% RH conditions in 2021 and 2022. Cut flowers cultivated at five locations nationwide with different cultivation seasons in 2021 and 2022 also showed similar long vase life, clearly indicating that the long vase life of our two cultivars were not due to the environment but the characteristics of cultivars.