Green Global
Foundation   Journal
...an emerging window for scientific research and publication across the globe

EFFECT OF LOW TEMPERATURE AT DIFFERENT GROWTH STAGES ON PHOTOSYNTHESIS, GRAIN GROWTH AND YIELD OF AMAN RICE VARIETIES (Pages : 13 - 17)

Temperature is one of the most important environmental factors influencing crop growth, development and yield processes. Temperature is becoming the major concern for plant scientists worldwide due to the changing climate. A pot experiment was conducted with five varieties viz., Binadhan-4, Binadhan-7, Binadhan-11, Binadhan-12 and Binasail in pot yard and the plant growth chamber at Bangladesh Institute of Nuclear Agriculture, Mymensingh during July to December 2014 to assess the effects of low temperature (20°C) at different growth stages on photosynthesis, grain growth and yield and to find out the variety tolerant to low temperature. Five temperature treatments viz., Ambient, 20°C at tillering stage, 20°C at panicle initiation stage, 20°C at booting stage and 20°C at flowering stage were imposed for 7 days at each respective growth stage and then plants were allowed to grow at ambient temperature up to maturity. For grain growth studies two temperature treatments, Ambient and 20oC were applied from fertilization to grain maturity. Ten grains were harvested from selected panicles of three plants of each treatment at 3 days interval starting from fertilization to maturity. During grain growth photosynthetic rate, chlorophyll content of flag leaf and dry weights of those grains were recorded. Photosynthetic rate, chlorophyll content of flag leaf, grain dry matter accumulation, the number of total tillers and effective tillers plant-1, filled and unfilled grains panicle-1, 1000-grain weight and grain yield were significantly affected by temperature treatments. Temperature treatments did not affect the number of total tillers plant-1 and panicle length. However, low temperature (20°C) at flowering stage affected grain yield more compared to other temperature treatments and found to be more sensitive. Grain dry matter accumulation gradually increased but photosynthetic rate in flag leaf decreased from fertilization to maturity. The rice varieties achieved physiological maturity at 24 days and chlorophyll content in flag leaves was stable up to 16 days after anthesis. The highest photosynthetic rate, grain dry matter accumulation and grain yield were found in Binadhan-7 under the treatments. So, Binadhan-7 seems to be tolerant to low temperature (20°C) compared to other varieties.Download