EVALUATION OF PHENOLOGY, GROWTH, YIELD AND STRESS TOLERANCE INDICES OF SIX WHEAT ( Triticum aestivum L.) VARIETIES GROWN UNDER LATE SOWN HEAT STRESS CONDITION

Abstract

The present investigation was conducted during wheat growing season of 2015-16 in the research farm of Wheat Research Centre, Dinajpur, Bangladesh to study the phenological changes, growth, yield and yield attributes of six wheat varieties under highly heat stress condition. The treatments consisted of two sowing dates viz., optimum sowing (15th November) and late sowing (15th January), and six recently released elite wheat varieties viz., Shatabdi, BARI Gom 26, BARI Gom 27, BARI Gom 28, BARI Gom 29 and BARI Gom 30. The experiment was laid out in split-plot design with three replications. Two sowing dates were arranged in main plots and six wheat varieties were arranged in sub-plots. In the present study, it was noticed that under high temperature stress, the crop completed its life cycle much faster than under normal temperature conditions which ultimately effect on final grain yield of wheat. All varieties in optimum sowing took more time to reach physiological maturity as compared to late sowing. The interaction effect of sowing dates and varieties was significant in respect of plants m-2 , tillers m-2 , LAI, biomass at 45 DAS (g), plant height at harvest, spikelet spike-1 , grains spike-1 , 1000-grain weight, harvest index, biomass at harvest (kg ha-1 ) and grain yield (kg ha-1 ). In optimum sowing (15th November), growth, yield and yield components were higher than late sown heat stress condition. In optimum sowing, significantly higher (5096.00 kg ha-1 ) grain yield was obtained from Shatabdi over BARI Gom 27 (3955.33 kg ha-1 ). However, in late sowing, significantly higher grain yield (1834.33 kg ha-1 ) was obtained from BARI Gom 30 over BARI Gom 27 (1353.00 kg ha-1 ). In optimum and late sowing, significantly higher (13587.33 and 6952.33 kg ha-1 ) biological yield was obtained from Shatabdi over BARI Gom 27 (10805.00 and 5113.00 kg ha-1 ). From the data on phenological variation, growth, yield and yield components as well as stress tolerance indices, it was found that November 15 is the suitable time for wheat sowing in Bangladesh. However, Variety shatabdi, BARI Gom 26, BARI Gom 29 and BARI Gom 30 may be recommended for late sown heat stress condition and may be used for future breeding program to develop heat tolerant variety.