日長，補光強度，遮光時期および最低夜温がシュッコンカスミソウ ‘アルタイル’の形態異常花序発生に及ぼす影響

As occurrence of abnormal inflorescence in Gypsophila paniculata ‘Altair’ is caused by environmental conditions, effects of day length, supplemental lighting strength, shading period and minimum night temperature on occurrence of abnormal inflorescence were investigated. Abnormal inflorescence was classified into four types : normal, pattern 1 (Short-flower stalk), pattern 2 (Coalescent two-flower stalk) and pattern 3 (Looping and irregular-flower stalk). Neither of 12h, 16h, 20h or 24h day length by fluorescent lamp, nor 24h by incandescent lamp affected occurrence of abnormal inflorescence. Effects of four levels of light intensity (fluorescent lamp : PPFD 1μmol・m−2・s−1, incandescent lamp : PPFD 3μmol・m−2・s−1, metal halide lamp : PPFD 14μmol・m−2・s−1 and high-pressure sodium lamp : PPFD 48μmol・m−2・s−1) were examined in 16h photoperiod. Occurrence of abnormal inflorescence was not affected by different light intensities, neither was it affected by shading period. Occurrence of abnormal inflorescence at 15°C was however significantly reduced compared to that at 8°C. In particular, patterns 2 and 3 at 15°C were significantly reduced compared to those at 8°C. There was a strong negative correlation between average night temperature from starting the treatment to flower budding (7.1°C, 9.0°C, 9.2°C, 11.6°C and 16.4°C) and incidence of pattern 3 (13.1%, 8.7%, 7.1%, 1.1% and 0.7%). Therefore, as average night temperature increased, occurrence of abnormal inflorescence decreased. The results show that low night temperature may be the main factor inducing occurrence of abnormal inflorescence.