Articles
EUSTOMA (LISIANTHUS) – ITS PAST, PRESENT, AND FUTURE
Article number
482_61
Pages
423 – 428
Language
Abstract
Eustoma or prairie gentian (Lisianthus) seeds have been commercially available in Japan since 1933. Three Eustoma species naturally occur in the United States of America.
Of the three E. grandiflorum (Raf.) Shinners has the largest flower.
This species has become very popular in Japan, and numerous cultivars have been developed.
The annual increase in production is remarkable and this popularity can be attributed to progress in breeding with new flower colors, diverse forms, excellent vase life and availability of flowers all year round.
Recently, nursery companies use F1 cultivars and distribute plug seedlings only.
Pink-or purple-edged white cultivars are most popular. Eustoma cultivation started in the cool climate zones in order to supply flowers during summer, now cultivation has also spread to warmer region in Japan.
Production from spring to autumn account for 80% of annual output.
New cultural techniques that prevent rosette-formation and advance or retard growth have resulted in a rapid expansion in production in the winter.
Thus Eustoma is now readily availability all year round by using selected cultivars growing in appropriate climatic locations.
In cool areas, seed sowing is done from March to April with flowering from September to October in unheated greenhouse.
By heating and lighting, harvest period can be extended to November.
On the other hand, in warm areas, due to high summer temperatures, seedlings remain in rosettes without bolting.
To overcome this problem, various methods have been used to prevent seedlings from rosetting or, as is currently preferred, to cool artificially the rosetted seedlings.
With the latter method and with suitable cultivars, this precise technique guaranteed success and uniformity of flowering and so ensure its rapid commercial adoption.
Of the three E. grandiflorum (Raf.) Shinners has the largest flower.
This species has become very popular in Japan, and numerous cultivars have been developed.
The annual increase in production is remarkable and this popularity can be attributed to progress in breeding with new flower colors, diverse forms, excellent vase life and availability of flowers all year round.
Recently, nursery companies use F1 cultivars and distribute plug seedlings only.
Pink-or purple-edged white cultivars are most popular. Eustoma cultivation started in the cool climate zones in order to supply flowers during summer, now cultivation has also spread to warmer region in Japan.
Production from spring to autumn account for 80% of annual output.
New cultural techniques that prevent rosette-formation and advance or retard growth have resulted in a rapid expansion in production in the winter.
Thus Eustoma is now readily availability all year round by using selected cultivars growing in appropriate climatic locations.
In cool areas, seed sowing is done from March to April with flowering from September to October in unheated greenhouse.
By heating and lighting, harvest period can be extended to November.
On the other hand, in warm areas, due to high summer temperatures, seedlings remain in rosettes without bolting.
To overcome this problem, various methods have been used to prevent seedlings from rosetting or, as is currently preferred, to cool artificially the rosetted seedlings.
With the latter method and with suitable cultivars, this precise technique guaranteed success and uniformity of flowering and so ensure its rapid commercial adoption.
Authors
K. Ohkawa, E. Sasaki
Keywords
F1 cultivar, seedling, rosette, artificial cooling
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