Experimental site: The field experiment was carried out at the experimental field of Bangladesh Institute of Nuclear Agriculture (BINA), Mymensingh, Bangladesh during November, 2012 to March, 2013. The soil of the experiment area was silty loam and belongs to the old Brahmaputra Flood Plain (AEZ-9) Alluvial Tract. The selected site was a medium high land and the pH of the soil was 6.67 with organic matter content of 1.05%. The experimental area was situated in the subtropical climatic zone, characterized by heavy rainfall, high humidity, high temperature and relatively long day during kharif season (April-September) and low rainfall, low humidity, low temperature and short day period during rabi season (October-March). Rabi season is favorable for tomato cultivation. The total rainfall of the locality was 414.7 mm during the experimental period.
Experimental materials and design: Experiment was two factorial where two tomato cultivars viz., Binatomato-4 and Binatoamto-5 were collected (Bangladesh Institute of Nuclear Agriculture, Mymensingh, Bangladesh) and used as factor B, on the other hand five defoliations viz., 0, 3, 6, 9 and 12 leaves removal out of 16 leaves at the beginning of flowering as factor A. The experiment was laid out in pot yard in a Randomized Complete Bock Design (RCBD) with four replications. The soil in the plots were well mixing with the given amounts of urea, triple superphosphate, muriate of potash, gypsum and cowdung at the rate of 3.70, 2.15, 1.30, 0.80 and 150 g per pot corresponding to 300, 160, 140, 40 and 10000 kg ha–1, respectively. Earthen pots of 30 cm diameter and 35 cm height were used for the experiment. The pots of the experiment were filled with 12 kg of soils. The seeds of each genotype were sown in the seed bed on November. Two seedlings were sown in each pot on 30 November, 2012. Finally, they were thinned to one seedling after 20 days of transplanting. The seed beds were prepared in iron sheet (50×60 cm). After sowing, the seeds were covered with light soil. Proper care was taken to raise healthy seedlings. Earthen pots of 30 cm diameter and 35 cm height were used for the experiment. The pots of the experiment were filled with 12 kg of soils. Plant protection measures were taken at 55 and 70 Days After Transplanting (DAT) against fruit and shoot borer by spraying Kormil 72 MZ WP @ 0.25%. To prevent the plants from fungal infection, Dithane M-45 was applied @ 2 g L–1 at 15 days interval. After 30 DAT, each plant was staked with bamboo sticks to keep them erect and to protect from damage by storm and high speedy winds.
Data collection and statistical analysis: Fruits were harvested at 5 days intervals during maturity and ripening stage. The maturity of the crop was determined on the basis of red color of fruits. At harvest, yield and plant characters like plant height (cm), number of branches per plant, number of leaves per plant, number of flowers per plant, number of flowers per cluster, number of fruits per cluster and number of fruits per plant were measured from each selected plants. Number of effective flower clusters and non-effective flower clusters per plant were counted of the sampled plant at 80 DAT. Moreover, leaf area of two plants in treatment was measured by automatic leaf area meter and average leaf area per plant and the straw yield was recorded by drying (80°C±2) for 48 h and calculated from summation of leaves, stem and roots weights were taken in an electronic balance. Besides these, few parameters were calculated by the following formula:
The collected data were analyzed statistically following the analysis of variance (ANOVA) technique and the mean differences were adjudged by Duncan’s Multiple Range Test (DMRT) using the statistical computer package program, MSTAT-C.