Genetic improvement of flower vase life is an important breeding target for ornamental plants. As the vase life of cut dahlia (Dahlia variabilis) flowers is very short, we initiated a conventional crossbreeding research program in 2014 to improve it. We evaluated the vase life of dahlia seedlings during summer (from July to early September) to develop dahlias that grow and bloom under high temperatures and have excellent vase life for Japanese summer conditions. Crossing and selection over five generations greatly improved vase life. The mean vase life increased from 4.4 days in the 1st generation, derived from 22 parental cultivars, to 8.0 days in the 5th generation, a net increase of 3.6 days. Mean vase life increased significantly by 1.6 days from the 4th to the 5th generation, indicating continued improvement. The mean vase life of the 12 lines selected from the 3rd and 4th generations ranged between 6.0 and 15.9 days in distilled water and from 7.8 to 14.6 days in GLA solution (10 g·L⁻¹ glucose, 0.5 mL·L⁻¹ CMIT/MIT [isothiazolinone derivatives], and 50 mg·L⁻¹ aluminum sulfate). Vase life was further extended by 0.5 to 4.0 days using 6-benzylaminopurine (BA) sprays compared to GLA alone. In particular, the 4th-generation line 003-15 vase life was 13.8 to 15.9 days (2.5× that of ‘Kamakura’, a leading white dahlia cultivar in Japan) in distilled water, 12.0 to 14.6 days (1.8× to 2.2×) in GLA, and 13.9 to 15.3 days (1.7× to 1.9×) in GLA+BA in winter and spring. Cut flowers of line 003-15 harvested under high temperatures in July–August and at 28°C with GLA treatment also had long vase life. The pedigree of line 003-15 suggests that genes related to long vase life derived from ‘Micchan’ (with a long vase life) may have accumulated or duplicated in line 003-15. Finally, four selected lines, including 003-15, had high ethylene sensitivity, as 10 μL·L⁻¹ ethylene treatment caused petal abscission in 2.0 to 2.8 days.

花瓶寿命的遗传改良是观赏植物的重要育种目标。作为切花大丽花（ Dahlia variabilis）的瓶插寿命）花很短，我们在2014年启动了常规杂交育种研究计划来改进它。我们评估了夏季（从七月到九月初）大丽花幼苗的瓶插寿命，以开发在高温下生长和开花并在日本夏季条件下具有优异瓶插寿命的大丽花。经过五代的杂交和选择大大提高了瓶插寿命。22个亲本品种的平均瓶插寿命从第一代的4.4天增加到第五代的8.0天，净增加了3.6天。从第 4 代到第 5 代，平均瓶插寿命显着增加了 1.6 天，表明持续改善。第3代和第4代的12个品系在蒸馏水中的平均瓶插寿命为6.0~15.9天，在GLA溶液（10 g·L）中的平均瓶插寿命为7.8~14.6天。⁻¹葡萄糖、0.5 mL·L ⁻¹ CMIT/MIT [异噻唑啉酮衍生物]、50 mg·L ⁻¹硫酸铝）。与单独使用 GLA 相比，使用 6-苄氨基嘌呤 (BA) 喷雾剂的瓶插寿命进一步延长了 0.5 至 4.0 天。特别是，第 4 代品系 003-15 的瓶插寿命为 13.8 至 15.9 天（日本主要白色大丽花品种“Kamakura”的 2.5 倍），在蒸馏水中为 12.0 至 14.6 天（1.8 倍至 2.2 倍）冬季和春季，GLA 为 13.9 至 15.3 天（1.7×至 1.9×），GLA+BA 为 13.9 至 15.3 天。003-15品系的切花在7月至8月高温和28°C条件下采收并经过GLA处理也具有较长的瓶插寿命。品系003-15的谱系表明源自“Micchan”（具有长瓶插寿命）的与长瓶插寿命相关的基因可能已经在品系003-15中积累或复制。最终筛选出003-15等4个品系具有较高的乙烯敏感性，为10 μL·L ^-1乙烯处理导致花瓣在2.0至2.8天内脱落。