The experiment was carried out at the Plant Physiology Field of Horticulture Research Center, Bangladesh Agricultural research Institute (BARI), (23.99287 E), 90.41127 E)Gazipur during October 2017 to May 2018 to investigate the influence of planting based temperature on physio-morphological characters and yield potentiality of tomato varieties in different sowing time. The experiment consisted of 8 sowing time i.e. October 30 (T1), November 15 (T2), November 30 (T3),December 15 (T4), December 30 (T5), January 15 (T6), January 30 (T7), February 15 (T8) were considered as factor A and two open pollinated tomato varieties viz., BARI Tomato -16 (V1), BARI Tomato- 17 (V2) considered as factor B. The experiment was laid out in RCBD (factorial) with three replications. The unit plot size 2.00 m2 (2.00m x 2.00 m) with 20 plants. Therefore, each unit plot occupied 10 plants. Thirty day-old seedlings (4 leaf stage) were transplanted on 30 October, 2017 with a spacing of 50 × 40 cm. Cowdung @ 10 t, and Nitrogen (N), Phosphorous (P), Potassium (K), Sulphur (S), Zinc (Zn), Boron (B) were applied @ 200, 30, 125, 10, 4, and 1.5 kg/ha. The entire quantity of cowdung and P from TSP, S from gypsum, Zn from Zinc sulpate and boron from boric acid (medicated) and half of K from MoP will be applied during land preparation. The remaining half of K and entire N were applied in 3 equal installments at 20, 40 and 60 days after transplanting. Fruit harvest started at January 15, 2018 and continued to May 15, 2018. The data were recorded on pant height, number of primary branches/plant, no. of inflorescences/plant, no. of fruits/ inflorescence, no. of fruits/plant, individual fruit weight (g), fruit length and fruit width, chlorophyll content in leaves (CCI value), photosynthetic yield (Fv/Fm), dry matter accumulation of plant, fruit yield, fruit yield/plant; per plot yield was then converted to per hectare yield. Data on CCI (Chlorophyll Content Index) was taken by Chlorophyll Content Meter (Model: CCM-200, Opti-sciences, USA). The changes in fluorescence yield reflect changes in photochemical efficiency and heat dissipation. The polyphasic rise of fluorescence transients was measured by an ADC Infrared Gas Analysis plant Efficiency Analyzer (PEA, Handsatech Instruments Ltd., King’s Lynn, UK). The initial fluorescence (F0), maximum fluorescence (Fm) were analyzed and quantum efficiency of open photosystem II centres-quantum yield (Fv/ Fm) was calculated. The leaf discs were previously adapted to the dark for 20 minutes. The fluorescence data were collected every day at 10.00 am to 2.00 pm from initial to end of the experiment. Fo is the amount of light absorbed initially to raise the fluorescence from a low level to maximum value Fm after dark adaptation. Fv = Fm - F0 which is the variable. Ratio of Fv/Fm is a dark adapted test used to determine maximum quantum yield. This ratio is also an estimate of the maximum portion of absorbed quanta used in PSII reaction centers. The analyses were done following the software STATISTICA, Version 5 (Statsoft France, 1997). The significance of the difference among the means was evaluated by the Least Significant Difference Test (LSD) at 5% level of probability. The meteorological information (monthly) collected from Agro meteorological Division, BARI, Gazipur during 1st October, 2017 to April 2018.