In order to establish a improved selection method for the late bolting radish, the Jinjoodaepyong was used as the test variety. Twenty-four hours of illumination with 5,000 lux was regarded as the sufficient day length condition while natural conditions in a PE film house in November as deficient conditions in this study conditions. In combination with the day length conditions, the sufficient low temperature or the deficient low temperature treatment were provided by the different duration of vernalization at 5℃.
The test giants were cultivated under the sufficiency day length and the deficiency low temperature, the deficiency day length and the sufficiency tow temperature, the deficiency day length and the deficiency low temperature, the sufficiency day length and the sufficiency low temperature conditions.
And then, their seeds were seperately harvested from early bolting plants and late bolting ones judged by the number of differentiated leaves before dower bud initiation. The seeds were cernalized at 5℃ for 0, 3 and 5 days respectively and then grown under the conditions of 25℃, and 31 hours day length of 5,000 lux.
The precious generations were also included in these studies.
Accordingly, the selection methods for early and into bolting plants were settled as follows;
1. The sensitive or insensitive plants against the day length are to be selected under the sufficiency day length and deficiency low temperature conditions.
2. The sensitive or insensitive plants against the low temperature are to be selected from the deficiency day length and sufficiency low temperature condition.
3. The sensitive or insensitive plants against both the low temperature and the day length are to be selected from the sufficiency day length and sufficiency low temperature. However, in case of the sensitive plant selection, their selection was apt io become intensive because only a little variation is expressed in the number of differentiated leaves according to the fully promoted reproductive growth.
4. The negative correlation was recognized between the number of differentiated leaves and the elongation of flower stalk.
On the other hand, the positive correlation was recognized between the number of differentiated leaves and the days to anthesis.
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