1994 Volume 63 Issue 3 Pages 653-662
Recently Eustoma grandiflorum (Raf.) Shinn. became popular as an ornamental because of its floral colors and longevity. Although 80% of the crop in Japan in concentrated in the summer season, seedlings sown during the summer form rosettes which limit their production. The research reported here was conducted to seek desirable cultivars for the winter production based on the response to sowing date and growing conditions. Furthermore, the relationship between temperature during stem elongation and growth of lateral buds after cutting was sought.1. Seedlings sown from June to August gave rise to rosette formation, regardless of cultivars, however, direct sowing of coated seeds prevented rosetting.
2. Seedlings sown on July 10 exhibited rosette growth with delayed bolting under high temperature. However they showed normal stem elongation after a few months when kept at 15°C or lower at night. High temperature and long day stimulated bolting and flowering on the seedlings sown on September 11.
3. The scapes on 20%of the bolted plants sown on June 23 had less than half the number of nodes and the length was half that of the flower stalk produced on the same plants the following summer. Differences between the two crops depended on cultivars.
4. To determine the effects of temperature on growth of lateral buds on the main stems, plants were grown at different temperatures from planting to cutting flowers. Growth of lateral buds on plants grown under high temperatures formed rosettes, whereas those grown at 15/30°C (night/day) bolted without having a basal cluster of leaves.