Development of new dahlia cultivars ‘Eternity Peach’ and ‘Eternity Shine’ with long vase lives

Improvement of flower vase life is an important breeding target in determining quality and the ability to satisfy consumer preferences. 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 we repeatedly crossed and selected promising offspring with long vase lives for five generations, from 2014 to 2021. Third-generation line 828-18, which has beautiful gradation flower color with a pink and white center, and line 937-C58 (‘Namahage Cute’ × second-generation line 628-48) with deep pink flowers were judged in 2022 to be suitable as new cultivars. We registered them and released them as ‘Eternity Peach’ and ‘Eternity Shine’ in 2023. These two new cultivars have genetically determined long vase lives of 8.0 to 10.7 days (1.4× to 2.0× that of ‘Kamakura’, a leading white dahlia cultivar in Japan) in distilled water, 9.5 to 11.4 days (1.4× to 1.8× ‘Kamakura’) in GLA solution (10 g L^-1 glucose, 0.5 mL L^-1 CMIT/MIT (isothiazolinone derivatives), and 50 mg L^-1 aluminum sulfate), and 10.1 to 11.6 days (1.4× to 1.6× ‘Kamakura’) in GLA solution + 6-benzylaminopurine spray, under 23°C, 12-h photoperiod, and 70% RH. Cut flowers of ‘Eternity Shine’ grown under high temperatures in July-August and at 28°C with GLA treatment also had a long vase life. Moreover, cut flowers of ‘Eternity Shine’ had high transportability. After long-distance transport, ‘Eternity Shine’ kept its ornamental value over 10 days.