Abstract
The experiment was conducted in two consecutive crop seasons (2015-16 and 2016-17) at Regional Agricultural Research Station (RARS), Hathazari, Chattogram during Rabi season (November to March) with 3 duplicate laid out Randomized Complete Block Design (RCBD) to compare the rehearsal of high-placed outcome, early maturing and heat tolerant varieties under increasing temperature. BARI released early maturing wheat varieties were used for optimum sowing time and heat tolerance as an adaptive mechanism suffering from terminal heat stress. Six heat-tolerant early maturing wheat varieties were (BARI Gom 25, BARI Gom 26, BARI Gom 27, BARI Gom 28, BARI Gom 29, and BARI Gom 30). The highest crop output was gained from BARI Gom 30 (4.33 t/ha) followed by BARI Gom 26 (4.06 t/ha) in a couple of years. The lowest yield was found from BARI Gom 27 (2.66t/ha) followed by BARI Gom 29 (3.53 t/ha), BARI Gom 28 (3.36 t/ha), and BARI Gom 25 (3.13 t/ha) both years. Crop output of wheat and amount of spike showed significant difference and rest of the parameters were insignificant. The earliest maturing variety was BARI Gom 30 and produced a maximum crop yield than others. BARI Gom 30 showed a maximum benefit-cost ratio (BCR) of 1.73 and BARI Gom 27exhibited the lowest benefit-cost ratio (BCR) of 1.06. This result of the experiment showed that early high yielding variety and the best adaptive variety was BARI Gom 30 among the six varieties in Chattogram.