Tofazzal Hossain

Alleviation of drought stress in maize by exogenous application of gibberellic acid and cytokinin

The study was conducted to investigate the ameliorative roles of GA3 and CK on adverse effects of drought in maize. Drought stressed maize plants were applied with GA3 and CK at 50, 100, and 150 mg L−l as foliar spray at the vegetative and the reproductive stages. Plant height, internode length, stem diameter, leaf chlorophyll index, and dry matter production were significantly affected by drought. In most cases, GA3 and CK significantly improved the depressed plant traits, but in varying degrees depending on the growth stage encountering hormones, and their types and concentrations. Both GA3 and CK were found to be very effective in alleviating drought-imposed adverse effects on maize at the vegetative phase. Such alleviating effects varied depending on the concentration of the hormones. Application of CK at 150 mg L−l was excellent resulting in a 106% yield advantage compared to drought stress and 79.9% increase relative to well-watered controls. Conversely, GA3 at 50 mg L−l performed well showing 78.8% increase in grain yield. However, both GA3 and CK had very little effect on improving the depressed growth and yield attributes in maize at the reproductive phase. The relative yield advantages for the hormones were mainly attributed to improving the cob and seed-bearing capacity of drought-stressed maize plants.

Evaluation of the physiological quality of wheat seed as influenced by high parent plant growth temperature

To examine the effect of high temperature during seed development and maturation on seed quality of wheat, seeds of four heattolerant and two heat-sensitive wheat genotypes obtained normal and high temperature growing conditions were tested for quality. High parent plant growth temperature during seed development and maturation resulted in poor seed quality. The effect of parent plant growth temperature on seed germination and speed of germination was inconsistent between heat tolerant and heat-sensitive wheat genotypes. Seed vigor as indicated by seed density, conductivity of seed leachates, seedling dry weight, production of normal seedlings, seed reserve utilization efficiency, and seedling emergence were reduced in all wheat genotypes due to higher parent plant growth temperature but heat-sensitive wheat genotypes were affected more than the heat-tolerant genotypes.

Response of radish to varying levels of irrigation water and fertilizer potassium on clay terrace soil of Bangladesh

A field experiment was conducted in the rabi (dry) season of 1998–99 on a clay terrace soil of Bangladesh, in order to study the effects of irrigation and potassium (K) fertilization on the yield, total water use, and water use efficiency of radish. Both irrigation and K application were found to be indispensable for increasing the yield of radish, due to their individually significant impact on the yield. The interaction effect of irrigation and K application was insignificant, but the highest yield of 30.1 Mg ha−1 was obtained under the highest levels of irrigation and K application (four irrigations with 160 kg K2O ha−1) as the positive effects of both treatments on the radish yield. From the economic viewpoint, the yield of 29.9 Mg ha−1 under four irrigation levels with 120 kg K2O ha−1 gave the highest net benefit. The total water use in this case was 101 mm, having the water use efficiency 297 kg ha−1 mm−1. Based on the acceptable economic yield, high water use efficiency, and the maintenance of proper soil fertility, four irrigation levels and K application at the level of 120 kg K2O ha−1 proved to be the best combination for the sustainable radish cultivation in Shallow Red–Brown Terrace Soil of Bangladesh.

Variation of Wheat Cultivars in Their Response to Elevated Temperature on Starch and Dry Matter Accumulation in Grain

Three wheat cultivars, namely, BARI Gom 25, BARI Gom 26, and Pavon 76, were sown in experimental field of Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, in Bangladesh, on 18 November, 2013. Two temperature regimes, namely, normal (23°C in open field) and elevated (6 ± 1°C higher compared to open field mean air temperature in polythene chamber) temperature, were created immediately after anthesis to investigate the response of wheat cultivars to heat stress. Elevated temperature cuts back the duration of grain filling by 5 days in BARI Gom 25 and BARI Gom 26 and 10 days in Pavon 76. Starch synthesis was also cut back by the same duration in respective cultivars under elevated temperature condition. Results indicate that failure of conversion of sugar to starch rather than limited supply of sugar under high temperature condition was responsible for shortening of grain filling duration in all wheat cultivars. However, the response of elevated temperature on grain starch and main stem grain dry matter was less profound in BARI Gom 25 and BARI Gom 26 compared to Pavon 76 indicating their better tolerance to elevated temperature.