2.1 Site description 2.1.1 Location of the experiment was conducted in the WRC, BARI, Dinajpur over two consecutive years (2013-14 and 2014-15) in wheat-growing seasons (Nov. to April). The geographical position of the area is between 25º 44.574" N and 88º 40.344" E, and 40 m above sea level. The Agro-Ecological Zone (AEZ) of the area is the Old Himalayan Piedmont Plain (AEZ1). This zone has the largest wheat area and also produces the largest amount of wheat in the country. 2.1.2 Soil characteristics in the experimental field Soils of the experimental sites were analyzed before sowing wheat. The pre-seeding total soil N was 0.06%, indicating a deficiency in soil N. Soil available K was 0.18 meq 100 g-1 soil, and available P, S, Zn and B were 18.5, 5.5, 0.79 and 0.15 µg g–1 soil, respectively. Based on the critical level of these plant nutrients, K, S, Zn and B were low, but P was high. Soil pH was 5.3 and organic matter was 1.3%. 2.1.3 Temperature, humidity and rainfall in 2013-14 and 2014-15 Weather data on weekly average temperature, humidity and rainfall in both years were recorded regularly by the HOBO U12 Family of Data Loggers (MicroDAQ.com) at the meteorological station, at Dinajpur WRC. 2.2 Experimental design and treatments The experiment was conducted in a completely randomized block design with three replications. Treatments were three seeding rates (100, 120 and 140 Kg ha-1) and five elite existing wheat varieties (‘BARI Gom 24’, ‘BARI Gom 25’, ‘BARI Gom 26’, ‘BARI Gom 27’ and ‘BARI Gom 28’). The unit plot size (3×3 m) consisted of 15 rows, each 3 m long, and a row-to-row distance of 20 cm and a block-to-block distance of 1.5 m. 2.3 Experimental procedure and crop management 2.3.1 Variety, seeding rate, sowing time, seed treatment and insecticide In both wheat seasons, all varieties were sown in lines by hand on November 21. Seeding rate was as indicated for each treatment. Before sowing, seeds of all varieties were treated with a popular fungicide, Provax-200 WP, which contains carboxin and thiram (marketed by Hossain Enterprise CC Bangladesh Ltd., in association with Chemtura Corp., USA). Furadan 5G (containing Carbofuran, marketed by FMC International S.A. Bangladesh Ltd.) was broadcasted at 10 kg ha-1 for controlling soil-borne insects. 2.3.2 Fertilizer, irrigation, mulching and weeding Fertilizer N, P, K, S, Zn and B, respectively, at 100, 27, 40, 20, 10 and 1 kg ha-1 was applied as recommended by the WRC. During final land preparation, two-thirds of N and a full amount of the other fertilizers were applied as basal. The remaining N fertilizer was applied immediately after the first irrigation, namely 18 days after sowing (DAS), while second, third and fourth irrigations were applied at 50, 73 and 88 DAS. Mulching was done at 28 DAS and hand weeding at 45 DAS. 2.3.3 Data collection Initial plants m-2 was recorded at 12 DAS, while number of tillers m-2 was recorded at 30, 40 and 50 DAS. The crop was harvested on 28 March in 2014 (for the 2013-14 season), and 30 March 2015 (for the 2014-15 season). GY, biomass yield (BY), and yield-related attributes were recorded from a 2.5 × 2.6 m area from the center of each plot. Samples from the harvested area from each plot were bundled separately, tagged and manually threshed on a threshing floor. Bundles were thoroughly dried in bright sunshine before their weights were recorded. Data on plant height (cm), productive tillers m−2, spike length (cm), spikelets spike−1, grains spike−1, 1000-grain weight (g; TGW), GY (kg ha−1) and BY (kg ha−1) were recorded. GY and TGW were recorded at 12% moisture content (Hellevang, 1995), while BY at harvest was recorded on a sun-dry basis.