Abstract
Six experiments were conducted at Horticulture Research Centre of the Bangladesh
Agricultural Research Institute, Joydebpur during 1990 to 1995 to investigate into the prospects and
possibilities of using growth regulators and nitrogen for early, uniform and off-season production of
pineapple under Bangladesh condition.
Ethrel and CaC2 had significant effect on flower induction and fruit development in pineapple.
Ethrel and CaC2 induced flowering in more than 80% plants in off-season at least six months earlier
than those in the control. NAA did not show any beneficial effect in this regard. There was no
significant difference among different concentrations of the growth regulators. However, ethrel 500
ppm and CaC2 10000 ppm were found better economically.
Ethrel and CaC2 applied in January on 9 to 13-month-old plants induced 95 to 98 per cent of
plants to flower. Size and weight of fruits were increased with increasing age of plants at forcing. The
size of fruits in respect of length and weight ranged from 13.6 to 16.0 cm and 1140.7 to 1611.7g
respectively.
Earliest flowering was obtained by applying any of the growth regulators in May. It took only
13 to 15 days for first appearance of inflorescence from date of forcing. Flowering percentage was
highest in January forcing (98%) with NAA while it was highest in May application of ethrel and CaC2
which induced 100% and 93% of plants to flower respectively.
Crop duration was the lowest (487 days) in plants treated in May while it was the highest (579 days) in
November treated plants.
Ethrel and CaC2 improved fruit quality by increasing TSS, total sugars, ascorbic acid content
and acidity compared to those in NAA treated and control plants. Use of ethrel and CaC2 as flower
inductant in pineapple was profitable in terms of return compared to control plants. Maximum benefit
of using ethrel and CaC2 over control were 196 and 258% respectively.
Application of N@ 15 g per plant as urea fertilizer gave best result in respect of flowering, size
and weight of fruits and fruit yield. Dry matter content, TSS, total sugars and sugar to acid ratio were
increased but acid content decreased with increasing rates of nitrogen application.