著者

Takashi Onozaki Takuo Fujimoto

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.QH-049, (Released:2023-04-12)

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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.

著者

Mirai Azuma Takashi Onozaki Kazuo Ichimura

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.OKD-176, (Released:2018-09-27)

被引用文献数

8

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Cut dahlia (Dahlia variabilis) flowers have recently become popular in Japan, but have the disadvantage of only having a short vase life. Here, we sought to clarify which factors are responsible for this by investigating the effects of an antibacterial (CMIT/MIT) treatment and a combined glucose plus antibacterial (Glc + CMIT/MIT) treatment on the vase life of the cut flowers of 10 dahlia cultivars, as well as the bacterial growth kinetics in their vase solutions and the soluble carbohydrate contents of their petals. We found that the CMIT/MIT treatment extended the vase life of ‘Kamakura’, ‘Magic Pink’ and ‘Purple Stone’, all of which had relatively high numbers of bacteria in their vase solutions. By contrast, the Glc + CMIT/MIT treatment significantly extended the vase life of three cultivars and also increased the fresh weight of nine cultivars. A comparison of two cultivars with relatively long and short vase lives (‘Moon Waltz’ and ‘Port Light Pair Beauty’, respectively) showed that a longer vase life was related to a higher carbohydrate content in the petals. Together, these findings suggest that maintaining the carbohydrate level is important for extending the vase life of cut dahlia flowers.

著者

Takashi Onozaki Masahiko Yamada Masafumi Yagi Koji Tanase Michio Shibata

出版者

一般社団法人 園芸学会

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.OKD-080, (Released:2017-04-05)

被引用文献数

7

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Flower vase life of cut ornamental flowers, including carnations, is important in determining their quality and consumer preference for cut flowers. Therefore, we repeatedly crossed and selected promising offspring with long vase life for seven generations, from 1992 to 2008, in order to improve the vase life of carnation (Dianthus caryophyllus L.) flowers using conventional cross-breeding techniques. We investigated flower vase life, ethylene production at natural senescence, ethylene production after ethylene treatment (autocatalytic ethylene biosynthesis), response time to ethylene treatment (ethylene sensitivity), and flower diameter in six carnation cultivars used for initial breeding materials and a total of 123 selected lines from the first to seventh generations. Our results indicate that there was a large genetic variability in the five traits. Significant negative correlations were observed between flower vase life and ethylene production at natural senescence (r = −0.88**), between flower vase life and ethylene production after ethylene treatment (r = −0.90**), and between flower vase life and flower diameter (r = −0.92**). However, there was no correlation between flower vase life and ethylene sensitivity. Thus, the long vase life of selected carnation lines was strongly associated with a decrease in their ethylene production. Our results indicate that variation in flower vase life is not due to differences in ethylene sensitivity, but due to differences in ethylene production. Although flower size is an important floricultural trait for commercial production, crossing and selection for flower vase life resulted in a considerable reduction in flower diameter. The course of mean flower vase life over generations showed that selection was effectively made in the first to sixth generations. Repeatability for the flower vase life was roughly constant (0.3 to 0.4) in the first to sixth generations, but decreased to 0.12 in the seventh generation, suggesting a decrease in genetic variation in the seventh generation.

著者

Koji Tanase Takashi Onozaki

出版者

一般社団法人 園芸学会

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.MI-093, (Released:2015-12-11)

被引用文献数

6

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We investigated differences in flower longevity, ethylene production, and ethylene sensitivity among pot carnation cultivars by quantitative PCR analysis. The flower life of ‘Polaris’ was significantly longer than that of ‘Ariel’ (control cultivar), ‘Orange Duo’, and ‘Lemon Soft’. The flowers of ‘Polaris’ produced little ethylene, and had low expression of the ethylene biosynthesis genes DcACS1 and DcACO1. The transcript levels of senescence-related (SR) genes DcCP1, DcbGal, and DcGST1 increased in petals of ‘Ariel’, ‘Orange Duo’, and ‘Lemon Soft’ at senescence, but were very low in ‘Polaris’. These results suggest that the low ethylene production in ‘Polaris’ is caused by low expression of DcACS1 and DcACO1, as in long-life flowers of the cut carnation cultivars ‘Miracle Rouge’ and ‘Miracle Symphony’. The ethylene sensitivity of ‘Orange Duo’ and ‘Lemon Soft’ was lower than that of both ‘Ariel’ and ‘Polaris’. Petals of ‘Orange Duo’ and ‘Lemon Soft’ wilted, and inrolled more slowly than those of ‘Ariel’ and ‘Polaris’, despite the upregulation of ethylene biosynthesis genes (DcACS1 and DcACO1), DcCP1, DcbGal, DcGST1, and DcEIL3 in petals of all cultivars upon application of exogenous ethylene. These results imply that only the components related to the inrolling of petals are altered in these ethylene-insensitive cultivars.