Effects of Low Temperature Treatment of Imbibed Seeds of Eustoma grandiflorum (Raf.) Shinn. on Their Germination and Subsequent Bolting.

Effect of Re-drying Seeds after Wet Treatment at 10°C on the Germination and Growth of <i>Eustoma grandiflorum</i> (Raf.) Shinn

“…The numbers of days of priming for onion seeds (Dearman et al, 1986), spinach seeds (Masuda et al, 2005), and parsley seeds (Dursun and Ekinci, 2010) were 10, 7, and 2 days, respectively. On the other hand, in Eustoma, the effective number of days of WT10°C applied to seeds to promote growth was 35 days under dark conditions (Tanigawa et al, 2002). It seems that the difference in duration of WT10°C before RDT may affect the germination rate after RDT.…”

“…This decrease in the germination rate was also observed in Experiment 1 (data not shown). Tanigawa et al (2002) pointed out that WT10°C of seeds accelerated germination. The decrease in the germination rate after RDT may be caused by seeds in which radicle extension has started during WT10°C for 35 days.…”

“…According to Tanigawa et al (2002), the bolting rate of plants transplanted in July 28, 1998, was 100% when WT10°C was applied for 35 days. However, when WT10°C was applied for 21 or 49 days, the bolting rates decreased to 87.5% and 68.8%, respectively.…”

“…To overcome this serious problem, various methods have been developed. One of them is the wet treatment of seeds at low temperature, which is reported to promote bolting of Eustoma seedlings (Kageyama et al, 1990;Ohkawa et al, 1993;Pergola et al, 1992;Tanigawa et al, 2002). Unfortunately, this treatment is limited to growers who have large refrigerators.…”

Improvement of Eustoma grandiflorum (Raf.) Shinn. Cut Flower Quality for Early-Autumn Shipping with Long-Day Treatment Using Light Sources That Delay Flower Bud Formation

“…The main factor inducing rosette formation is found to be high temperatures above 25-28°C experienced in the period from sowing to the developmental stage of two leaf pairs (Azuma and Inubushi, 1988;Harbaugh et al, 1992;Ohkawa et al, 1991). Some useful techniques for avoiding high temperatures when raising seedlings have been developed: all-night cooling at 10-15°C (Kobayashi and Kondo, 1990); all-day artificial cooling at 25°C during the day and 15°C at night (Azuma and Inubushi, 1988;Kobayashi and Tanigawa, 1995); artificial cooling at 10-12°C of rosette seedlings in a cool-store with irradiation (Ohkawa et al, 1996;Takeda, 1995); and artificial cooling at 10-12°C of imbibed seeds (Tanigawa et al, 2002). The success of these cultivation methods has enabled the year-round production of cut flowers of Eustoma cultivars.…”