Experimental site and duration: In Bangladesh, The experimental site was the Horticulture farm of Sher-e-Bangla Agricultural University, Dhaka, Bangladesh, and the research was conducted from April 2006 to July 2006. The experimental location was lies in 23074” N latitude and 90035” E longitude with an elevation of 8.2 meters from sea level.
Plant material and soil The authority of Bangladesh Agricultural Development Corporation (BADC), Dhaka, Bangladesh supplied the cucumber local variety ‘Baromashi’ seed for the experimental purpose. The soil of the experimental site was slightly acidic (pH: 5.4-5.6) belonging to the Modhupur Tract which had medium high land.
Experimental design The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications. An area of 12 m x 8 m was divided into 9 equal blocks. The experiment consisted of four treatments (Control: untreated plant, T1: maleic hydrazide 200 ppm, T2: ethephon 300 ppm and T3: NAA 18 ppm). Each block had six pits and each treatment was replicated with three replications.
Cultural practices The experimental land was plowed on 23 March 2006 with the power tiller and then it was sun dried for 4 days. The recommended dose of fertilizers was applied and mixed thoroughly with the soil and weeds and stubble were removed manually. The pit size was 30 cm in length, 30 cm in width and 20 cm in depth. Irrigation and other necessary cultural practices were done regularly. Plants staking and vine management were done randomly for the proper growth and development of the cucumber plant. Malathion 57 EC and Ripcord were applied as per the manufacturing company’s recommendation. Furadan 10 G was applied @ 5 gm/pit during pit preparation.
Preparation of plant growth regulators (PGRs) solution Three different plant growth regulators were used in this experiment. “Crops Care” (NAA 4.5%), “Ripen-15” 42.5% ethephon and maleic hydrazide powder were used to prepare NAA 18 ppm, ethephon 300 ppm and maleic hydrazide 200 ppm solutions respectively. The solutions were prepared through the following procedures: a. Maleic hydrazide 200 ppm (T1): To make maleic hydrazide 200 ppm solution, 0.2 gm of maleic hydrazide powder was mixed with 2ml NH4OH solution. Then 2 ml surfactant was added with the solution for increasing the additive value. Then the solution was made up to 1000 ml by adding distilled water and shacked well. b. Ethephon 300 ppm (T2): For preparing ethephon 300 ppm solution, 0.705 ml “Ripen-15” was added with 2 ml of surfactant and then the solution was made up to 1000 ml by adding distilled water and shaked well. c. NAA 18 ppm (T3): NAA 18 ppm solution was made by adding 0.40 ml “Crops Care” with 2 ml of surfactant and the solution volume was made up to 1000 ml by adding the distilled water and shaked properly.
Application of treatments Plant growth regulators (PGRs) were applied in three installments. The first spray was done at 2 to 4 true leaves stage of seedlings with the hand sprayer on 26th April 2006. After seven (07) days of the first spray, the 2nd spray was done. And final spray (3rd spray) was done 10 days after the second spray to the leaves and twigs of cucumber plants with a knapsack sprayer. Data collection Six cucumber plants were randomly selected from each treatment from this research and following data were taken. Stem length (cm) Stem length was taken with the help of measuring tape in centimetre from the ground level to tip of the main stem from each plant. Data were taken for three times for each treatment and mean value was calculated. Number of primary and secondary branches per plant Primary and secondary branches were counted at the last harvest from each plant of the treatment and mean value was calculated. Mean value was calculated by the following formula -
Number of primary branches = Total number of primary branches/6.
Number of secondary branches = Total number of secondary branches/6.
Node number for 1st male and female flower Node number of each plant of every treatment was counted with the first appearance of the male and female flower. This data was taken three times and the mean value was calculated. Days required to 1st male and female flower The number of days required for first flower initiation from the sowing date for both male and female flower was recorded for every plant and average was calculated. Days taken to 50% flowering per plot Fifty percent flowering of both male and female flower recorded manually from sowing date. Data were recorded with three replications and then the observations were calculated. Total number of male and female flowers per plant The total number of the male and female flower of each plant was counted from first flower appearance and it was taken at three days intervals. The total number of male and female flowers was recorded from each treatment. Number of fruits per plant The total number of fruit of six plants was counted from the first harvest to the last harvest. After that the number of fruits of each plant was recorded by the following formula Total number of fruits/plant= Total number of fruits from six plants of each treatment/6. Fruit length and girth Fruit length and girth were taken with the help of measuring tape in centimeter. Girth i.e. breath of fruit was measured at the middle portion of fruits from each plot and their average was taken. The average length of the same fruits was also taken. Yield of fruits All matured fruits from every harvest of plants of each treatment were considered for the total yield. After that, the average yield of every plot was measured by an electric balance. The yield per hectare was calculated considering the area covered by the six plants. Statistical analysis MSTAT software was used to analyze the collected data for finding the significant variation of different parameters. F test (variance ratio) was performed to identify the variance of each data. The differences between the treatment means were evaluated by the LSD test at 1% or 5% probability.