This study was conducted to assess the morpho-physiological and yield performance of grain sorghum genotypes during the period from December 2013 to April 2014. A pot experiment was carried out at the grill house of the Department of Crop Botany, Bangladesh Agricultural University, Mymensingh. Geographically the experimental area is located at 24°75' North latitude and 90°50' East longitudes at the elevation of 18 m above the sea level. The soil of the experiment was collected from the Crop Botany Field Laboratory of Bangladesh Agricultural University, Mymensingh. The collected soil belongs under the agro-ecological zone of Old Brahmaputra Floodplain (Agro Ecological Zone- 9). 2.2. The experimental field was under subtropical climates characterized by heavy rainfall during the month of April to September and scanty rainfall during October to March. The monthly means of daily maximum, minimum and average temperature, relative humidity, total rainfall and sunshine hours received at the experimental site during the study period from December 2013 to April 2014. The seeds of twenty sorghum genotypes were used as the planting materials for this experiment. The twenty sorghum genotypes are as follows: V1=: BD 700, V2 =: BD 701, V3 : BD 702, V4: BD 703, V5 : BD 704, V6 : BD 705, V7 : BD 706, V8 : BD 707, V9 : BD 708, V10 : BD 709, V11 : BD 710, V12 : BD 712, V13 : BD 720, V14 : BD 721, V15 : BD 722, V16 : BD 726, V17 : BD 727, V18 : BD 728, V19 : 725, V20 : BD 729. In this experiment Poly Venyl Chloride pots were used. The diameter of each pot was 21 cm and height was 26 cm. Soils were collected from Crop Botany Field Laboratory of Bangladesh Agricultural University, Mymensingh. The collected soil was well pulverized and dried in the sun. Plant propagules and inert materials were removed from this soil. The dry soil was thoroughly mixed with manure and fertilizers before filling the pots. The pots of the experiment were filled with 9 kg of soils. The weight of 1 ha soil at the depth of 15 cm was considered 3 × 106 kg of soil. According to the rate of fertilizers were calculated as per kg of soil (BINA, 1999). For pot soil required fertilizers were three times than field soil. So, total amount of Urea (2.09g), TSP (0.99 g), MP (0.99 g), Gypsum (0.55 g), ZnSO4 (0.0879 g) and Boron (0.275 g) were mixed with sundry soil in each pot thoroughly. The single factor experiment was laid out in a Completely Randomized Design with three replications. As there were 20 genotypes, the total number of pots used in this study was 60 (20 × 3). Seeds were sown on 15 th December 2013. Ten seeds were sown in each pot and plants were thinned to two plants per pot at 30 days interval. The plants were uprooted carefully for data collection. The crop of each experimental pot was harvested separately at full maturity on 25 th April to 30 th April 2014. The harvested crop of each pot was bundled separately, tagged properly. The bundles were dried in sunshine and brought to a clean floor. Seeds and other plant parts were collected for each pot and were recorded data separately. Experimental data were recorded on two randomly selected plants from each pot at 30, 60, 90 and 120 days after sowing. The selected plants were collected and necessary information was recorded accordingly. Grain and straw yields were recorded pot wise on oven dry basis. The data on the following parameters were recorded: Growth and morpho-physiological characters- Plant height (cm), Number of leaves per plant, Leaf area (cm2), Leaf Area Index, Crop Growth Rate (g m-2 day-1), Total dry matter (g). Yield and yield contributing characters at harvest- Panicle length (cm), Panicle/plant, 1000-grain weight (g), Grain wt. /plant (gm), Grain yield (t ha-1), Straw yield (t ha-1), Biological yield (t ha-1). 2.8.1. Plant height Plant height was measured in centimeter by a meter scale at 30 days after interval from 30 days after sowing up to harvest from the ground surface to the top of the main shoot and the mean height was expressed in cm. Number of leaves per plant was counted at 30, 60, 90 days after sowing and at harvest. The leaves were counted and recorded from each plant. The plant parts such as shoot including leaves and roots were detached and were kept separately in oven at 80±2? for 72 hours. The oven dried samples were weighed for dry matter production. The total dry matter production was calculated from the summation of shoots and roots. No. of panicle plant-1 was counted at the time of harvest. One thousand cleaned dried grains were counted randomly from each sample and weighed by using a digital electric balance at the stage the grain retained 12% moisture and the mean weight were expressed in gram. After harvesting, the grains were removed from the separated panicle and then dried in sun for 2–3 days. Finally, grain weights were taken on individual pot basis at moisture content of 12% and then converted into t ha-1. 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.