2012 Volume 11 Issue 3 Pages 363-369
In the winter culture of cut Eustoma grandiflorum flower production, blasting of flower buds often occurs, resulting in an delay of the harvest time. In experiment I, a four-hour night break using incandescent lamp (IL) was given from planting to harvest. Two genotypes of Eustoma (‘Rosina Rose Pink’, ‘Piccorosa Snow’) showed early flowering with low frequencies of blasting compared with those cultured under a natural day length (NL). In experiment II, ‘Bolero White’ was grown under NL until apical flower budding. Then, 20-h LD with two types of light source, IL and a fluorescent lamp (FL), was given from the apical flower budding to harvest. In addition IL was given in the flower bud formation or mature stage. Lighting with IL did not affect the flowering time of the secondary lateral flower but lowered blasting emergence and elongated the stem at the upper nodes. Furthermore, the peduncle in the 3rd flower shortened by lighting with IL in the flower bud formation stage, but it elongated by the same treatment in the mature flower bud stage. The present results demonstrate that lighting with IL promotes flowering and lowers blasting emergence.