Low temperature effect on flower and fruit development of 'Tainung No 17' pineapple

Pineapple is one of the most important commercial fruits of Taiwan. Natural flowering occurs in late November to February and can result in a period of oversupply of pineapple fruit. Forced flowering is a way to prevent oversupply but its effect becomes unstable in the winter season. The purpose of our research was to find out the effect of low temperature on forced flowering of 'Tainung No 17' pineapple during the winter season. The results showed that cold treatment(12 degrees C-8 h/3 degrees C-16 h for 3-5 days) at 6, 12, 17, or 22 days after flower forcing resulted in low flowering rate, malformation on fruits, low starch content, low titratable acidity and low total soluble sugar. On the other hand, plants which received cold treatment at 33 and 50 days after flower forcing showed no significant difference from the control in terms of fruit formation (shape and crown), starch content, titratable acidity and total soluble sugar. The overall results of this study indicated that chilling sensitive stage was within 22 days after flower forcing. Cold treatments during this stage caused low flowering rate and poor fruit development and quality.