Mirza Hasamuzzaman
Dept. of Agronomy, Sher - e - Bangla Agricultural University, Dhaka, Bangladesh
Masayuki Fujita
Dept. of Biosciences, Faculty of Agriculture, Kagawa University, Kagawa, Japan
M N Islam
Dept. of Soil Science, Sher - e - Bangla Agri cultural University, Dhaka, Bangladesh
K U Ahamed
Dept. of Agricultural Botany, Sher - e - Bangla Agricultural University, Dhaka, Bangladesh
Kamrun Nahar
Dept. of Agricultural Botany, Sher - e - Bangla Agricultural University, Dhaka, Bangladesh
Salinity, Rice, Stress, Growth, Yield.
Research field of Sher-e-Bangla Agricultural University, Dhaka, Bangladesh
Crop-Soil-Water Management
The experiment was conducted at Sher-e-Bangla Agricultural University, Dhaka, Bangladesh, during Aman season (August to December, 2008). Geographically, the experimental area was located at 24º75´ N latitude and 90º50´ E longitude at the elevation of above 18 m of sea level. The soil of the experimental pot was silty - loam having noncalcarious properties. Earthen pots were used in this experiment. The size of the pot was 30 × 20 cm. The soil was collected from 0-15 cm depth. The collected soil was well pulverized and dried in the sun and decomposed cowdung was mixed with the soil. A basal dose of triple super phosphate (TSP), muriate of potash (MP) and gypsum were used as the source of phosphorus, potassium and sulphur applied at the rate of 180 kg ha-1, 100 kg ha-1 and 20 kg ha-1, respectively (1ha = 3× 10 6 kg fresh soil) at the time of final pot preparation. Urea @ 150 kg ha-1 was applied as 3 equal splits. There were 4 different rice varieties used in the experiment - BR11, BRRI dhan41, BRRI dhan44 and BRRI dhan46 which were collected from Bangladesh Rice Research Institute (BRRI). Seeds and rice plant were subjected to exposure in different salinity concentration of 0, 30, 60, 90, 120 and 150 mM NaCl. The experiment was carried out in a Randomized Complete Block Design (RCBD) with 3 replications as factorial arrangement. Seeds were allowed for germination in petri dishes having the different salinity concentration. Pregerminated seeds were sown in wet nursery bed and care was taken to raise the seedlings in seedbed. Each thirty - day - old seedling w as transplanted in a separate puddled pot with different salinity concentration. Seedling in some hills died off, and these were replaced by gap filling after one week of transplanting with the seedling from the same source. Intercultural operations were done as required . About 5 - 6 cm water layer was maintained in the pot until the crop attained maturity. Water was added regularly as per assigned salinity concentrations. After providing an exposure of salinity treatment for a period of one and two weeks, number of dead leaves per plant, were counted and percent increase in mortality of leaves were calcula ted comparing the plants growing under non - saline conditions (0 mM NaCl). Relative water content in shoot was determined with following equation:
RWC = {(Fresh weight - Dry weight)/(Turgid weight - Dry weight)}X 100
Fresh weight of the plants were measured and the plants were dried at 105ºC for 24 h until they reached constant weight for the determination of dry weight. To determine the turgid weight, samples were soaked in distilled water for 4 h at room temperature (approximately 20ºC) and then turgid weight was measured (Fletcher et al., 2006). Leaf area was measured at maximum tillering stages. The leaf area was measured with an automatic leaf area meter (Model AAM, Hayshi Denkoh Co., Tokyo, Japan). Leaf area index was measured as follows:
LAI = Total leaf area/Ground area
Different yield components were recorded at maturity. Grain yield was recorded from each plant and then converted to tons per hectare. Grains were weighed at 14% moisture. Data were analyzed following Analysis of Variance (ANOVA) technique and mean differences were adjusted by the multiple comparison test (Gomez and Gomez, 1984) using the statistical computer based programme MSTAT-C v.2.1. (Russell, 1994) Means were compared by using DMRT test.
International Journal of Integrative Biology (A journal for biology beyond borders), IJIB, 2009,Vol.6,No.2, 85, ISSN 0973-8363
Journal