Location and duration: The experiment was conducted at the research field of Crop Physiology and Ecology Department, Hajee Mohammad Danesh Science and Technology University, Dinajpur-5200, Bangladesh under the Agro-ecological zone 1 (Old Himalayan Piedmont Plain) during March to May, 2018.
Experimental design, layout and treatments: The experiment was laid out in a randomized complete block design with three replications. The selected land area was divided into three equal blocks that represent replication. Each block was divided into eight plots where eight treatment combinations were randomly allotted. The unit plot size was 2.0 m × 2.0 m. The distances between plot to plot and block to block were 0.5 and 1.0 m, respectively. The treatments included two factors: 1) two growing conditions: i) control (no gibberellic acid) and ii) foliar application of gibberellic acid (300 ppm GA3) and 2) four cucumber varieties (Shohag, Sarothi, Sufala-1 and Shila).
Pit preparation, seed sowing and intercultural operations: There was one pit in every plot and the area of each pit was 25 cm × 25 cm. The pits were prepared with necessary manures and fertilizers according to cucumber cultivation manual (BARC 1997). Three seeds were sown in each pit at 1.5 to 2 cm depth and when the seedlings attained 10-15 cm height and hard enough then one healthy seedling was selected to keep in each pit and others were thinned out. Necessary intercultural operations such as weeding, stalking, vine management, irrigation and plant protection measures were taken when and as needed.
Preparation and application of GA3: To make 300 ppm solution of GA3, 300 mg of GA3 was dissolved in 10 ml of ethanol and was added with 1% Tween 20 in order to improve the spray retention. Then the solution was made up to 1000 ml by adding distilled water and shacked well to get 300 ppm. The prepared solution was applied in four installments. First spray was done at 2 to 3 leaves (fully expanded) stage of seedlings. The remaining three sprays were done at 7, 14 and 21 days after 1st spray to the leaves and twigs of the plants with a hand sprayer.
Data collection: Data were recorded on growth, flowering, and fruit yield attributes such as vine length, internodal distance, number of tendrils plant-1 , number of primary branches plant-1 , number of leaves plant-1 , days taken to first male and female flowering, days taken to 50% flowering, total number of male and female flowers plant-1 , number of fruits plant-1 , individual fruit weight, fruits yield plant-1 and fruit yield (t ha-1 ).
Statistical analysis: The data were analyzed by partitioning the total variance with the help of a computer using STATA program (Small stata 12.0) and the mean differences were adjusted by the Tukey’s Test at 5% level of probability.