Bangladesh Rice Research Institute Research Articles

Assessing Impact of BRRI Released Modern Rice Varieties Adoption on Farmers’ Welfare in Bangladesh: Application of Panel Treatment Effect Model

This study assesses the impact of Bangladesh Rice Research Institute (BRRI) released modern wet (Aman) season rice variety adoption on farmers‟ well-being in Bangladesh. Bangladesh Integrated Household Survey (BIHS) data collected by IFPRI were used for this study. The study applied difference-in-difference treatment effect and difference-in-difference quantile treatment effect models using unbalanced panel data to achieve the set objectives. Analysis revealed that BRRI released wet (Aman) season rice technology has a robust and positive effect on small farmers‟ welfare in Bangladesh as indicated by the level of increases in per capita household real income, increases in real aman rice income, and also increases in yield and decreases both in poverty gap and squared poverty gap over time. The marginal and near landless farmers have not gained significantly through adopting BRRI released modern variety over non-adopters in terms of all the indicators except aman rice yield. However, only yield of BRRI released modern wet (Aman) season rice technology has positive and significant impact on the marginal and near landless farmers. As such, BRRI variety adoption seemed to be conducive in increasing the level of yield of marginal and near-landless farms but it hardly helps them to overcome the poverty level, unless other equity-enhancing policy measures are undertaken. Overall, there was large scope for enhancing adoption of BRRI released rice variety in order to reduce the poverty level in rural areas. The current rice policy (rice self-sufficiency) appears to be supportive to help Bangladesh rice sector for achieving food security in the country.
 Bangladesh Rice j. 2019, 23(1): 1-11

Factors Affecting Adoption of BRRI Released Aus Rice Varieties in Mymensingh District

This study was carried out to evaluate the performance of BRRI cultivars, identifying criteria and constraints as well as factors influencing the intensity of BRRI cultivars adoption in <i>Aus</i> season on the farm households in Mymensingh district. The data were collected through structured questionnaires from a total of 390 randomly selected rice farmers from thirteen Upazila of Mymensingh district. The study employed descriptive statistics and Tobit censored regression to determine the adoption and yield status; and adoption intensity determinants. In addition to a total of thirteen FGDs and expert panel interview was conducted to verify the collected data. The results show that 82.04 percent of the area in Mymensingh district was cultivated with rice variety developed by Bangladesh Rice Research Institute (BRRI) with an average yield of 4.05 t/ha during the <i>Aus</i> season. The findings of the Tobit censored regression indicate that schooling, distance to the local market, training, price variation, taste and preference, amount of cultivated varieties, yield variability were the significant factors of the intensity of BRRI varieties adoption in <i>Aus</i> season. The study's results suggested that breeders should also emphasize the choice of farmers while developing varieties. In addition to developing new rice varieties, BRRI, Department of Agricultural Extension (DAE), Bangladesh Agricultural Corporation (BADC) and other seed producing organizations need to work together to provide the farmers with good quality seeds of BRRI varieties, which will increase the total production of the country, thus helping to ensure food safety.

Morphological Characterization and Diversity of T. Aman Rice Germplasm of Bangladesh

Fifty-four T. Aman rice landraces were studied for 11 morphological and yield contributing characters at Bangladesh Rice Research Institute during T. Aman 2016 season. The largest variation was observed for yield per hill with 53.6% CV, followed by 1000 grain weight (29.9), number of effective tillers per hill (22.8), culm diameter (18.8), leaf width (18.4), leaf length (18.1) and days to maturity (6.7) respectively. The longest leaf was recorded as 82.2 cm and that of culm diameter as 7.57 mm, grain length as 7.2 mm and LB ratio as 3.48. The shortest days to maturity (110 days) was observed in Kajal lata and plant height (86.6 cm) in Haijam. Indursail possessed the longest panicle (31.6 cm) and the highest yield per hill (24.3 g). Based on D2 values, all the germplasm were grouped into 15 clusters using Mahalonobis D2 statistic. The maximum numbers of germplasm (7) were grouped into the clusters IV with VI, whereas clusters III and XIII contained the minimum (1). The highest intra-cluster distance (1.0) was found in cluster II and the lowest (0.0) in clusters III and XIII, respectively. The inter-cluster D2 values ranged from 19.2 to 0.6 indicating wide range of diversity among the germplasm. Cluster XIII showed the highest leaf length (82.2 cm) and culm diameter (6.5 mm), cluster IX the highest effective tillers per hill (13), cluster II the lowest days to maturity (117), cluster XV the highest grain length (6.1 mm) and cluster I the highest grain LB ratio (2.97), while cluster VIII showed the highest yield per hill (22.0 g), panicle length (28.8 cm) and 1000 grain weight (25.2 g), respectively. Finally, the germplasm under clusters VIII may be selected for crossing with the germplasm from clusters XIII, IX, II, XV and I for developing high yielding varieties with improved panicle length, effective tillers per hill, growth duration and grain type.&#x0D; Bangladesh Rice j. 2018, 22(2): 13-22

Moisture Stress and Different Rates of Nutrients on Growth and Yield of Rice

The experiment was conducted at the Bangladesh Rice Research Institute (BRRI) Gazipur farm during Boro 2003-04 seasons to observe the moisture stress effects in relation to nutrient rates on growth and yield of rice. The treatments were three moisture stresses (NS= Always saturated condition i.e. 1-2 cm standing water; VPS= Withholding water at the vegetative phase i.e. 15 days after transplanting (DAT) to maximum tillering stage; RPS=Withholding water at the reproductive phase i.e. PI to flowering stage) and three fertilizer doses (F0= No fertilizer; HD= Half of the optimum dose and OD= Optimum dose i.e. 120-60-40-10-2 kg ha-1 of N, P2O5, K2O, S and Zn respectively). The treatments were applied in high yielding variety BRRI dhan29. The result showed that irrespective of nutrient rates, drought stress decreased plant height, tiller number and shoot dry weight. Unstressed plants (NS) produced the highest grain yield (3.14 to 6.51 tha-1) followed by vegetative phase stressed (VPS) plants (2.73 to 4.50 tha-1). The reproductive phase stressed (RPS) plants produced the lowest grain yield (2.54 to 4.20 t ha-1). Regardless of water stress, application of optimum dose (OD) of nutrients produced the highest grain yield followed by half dose (HD) of nutrients. No fertilizer treatment (F0) produced the lowest grain yield. Due to water stress, the highest grain yield reduction occurred in OD (22-32%) followed by HD (12-19%) and the lowest in F0 (4-15%).&#x0D; Bangladesh Rice j. 2018, 22(2): 23-30

Performance of Prilled Urea and Urea Super Granule by Applicators on Yield and Nitrogen Use Efficiency in Boro Rice

A field experiment was conducted on validation of prilled urea (PU) and urea super granule (USG) applied by applicators on yield and nitrogen use efficiency during Boro 2014 season at Bangladesh Rice Research Institute (BRRI) farm, Gazipur (AEZ 28). Six treatment combinations of different N doses and methods of N application were tested to compare urea-N application by PU and USG applicator for rice yield, N uptake and N use efficiency over urea broadcasting. Application of N as PU or USG through applicator has same effect on grain yield, N uptake and N use efficiency compared with urea broadcasting. Statistically similar grain yield were observed with N application as PU or USG @ 78 kg N ha-1 by applicator which was comparable with urea broadcasting @ 135 kg N ha-1. The N concentration and uptake in both panicle initiation (PI) and maturity stage were higher in USG deep placement than PU deep placement by applicators but the difference was not significant. Although agronomic use efficiency (AUE) of N was slightly higher in PU than USG applied by applicators but the recovery efficiency (RE) of N was higher in USG than PU.&#x0D; Bangladesh Rice j. 2018, 22(2): 63-69

Effect of Planting Time on Sheath Blight Disease of Rice in Bangladesh

Sheath blight (ShB) caused by Rhizoctonia solani is one of the major disease of rice (Oryza sativa L.) in Bangladesh. Effect of planting time on ShB disease of BRRI dhan49 was observed at the experimental plots of Bangladesh Rice Research Institute, Gazipur. Two field experiments were conducted to develop management strategy for controlling ShB during T. Aman 2010-11 seasons. Four planting dates viz. 15 July, 30 July, 15 August and 30 August were imposed to record the effect of planting time on incidence and severity of ShB disease on BRRI dhan49. Significant differences on the Relative Lesion Height (RLH) among the treatments were observed during both 2010 and 2011 seasons. For both the seasons, the highest RLH was recorded in plots transplanted on 15 August (62.1% in 2010 and 61.2% in 2011) because of the remaining high temperature, rainfall and humidity and the lowest in plots transplanted on 30 July (19.4% for both). Similarly, the maximum severity score was recorded in 15 August transplanting (7) and the minimum in 30 July (1) respectively. Percent disease index (PDI) was also varied significantly among the treatments for both the seasons. During both the years, the maximum PDI was recorded in 15 August (76.5 and 75.2% respectively) and the minimum in 30 July transplanting (20.4 and 20.1 respectively). However, the highest number of filled grains panicle-1 was counted in 30 July (151), followed by15 July transplanting (145) during 2010. But, it was the highest in 30 July (141), followed by 15 August transplanting (136) during 2011. Again for both the seasons, the lowest filled grains panicle-1 was recorded in 30 August transplanting (116 and 127). Similarly for both the years, the maximum grain yield was observed in 30 July (6.29 and 5.82 t ha-1 respectively), followed by 15 July (5.67 and 5.17 t ha-1) and the lowest in 30 August transplanting (3.80 and 4.27 t ha-1 respectively). However, 1000 grain weight was 20 g in each date of transplanting during both the seasons. Finally, Integrated Disease Management (IDM) packages need to be developed by using appropriate planting time, cultural practices and fungicides to control ShB disease of rice.&#x0D; Bangladesh Rice j. 2018, 22(2): 55-62

Valuation of Weather Manifested Rice Cultivation in Bangladesh: A Way Forward

Good crop yield entirely depends on good management practice and quality management of crops allied with authentic weather forecasting can reduce risk, crop damage, cost of production and increase the yield as well. Bangladesh Rice Research Institute (BRRI) had aimed this study for quantifying the financial benefit of forecasting and validating micro climatological factors and their impacts on paddy production through experimentation and arranging for weather based agro meteorological advisory service delivery to the farmers applying the tools of ICT. A next-generation meso-scale numerical weather prediction system, WRF (Weather Research and Forecasting) model was used for generating atmospheric simulations based on real data (observations, analyses or idealized conditions). Field experiment was conducted in the areas of five different agro microclimatological conditions for Boro rice production, namely; Gazipur, Habiganj, Rajshahi, Barishal and Satkhira. Then the experimental fields were managed according to the weekly management advisory based on weather forecasts. Results obtained suggest that the application of weather predictability accrued a comparative rice yield benefit of 9-12% and a 3–5% reduction in the cost of cultivation. Countrywide application of agro-meteorological advisory service may pave the way for averting adverse climatic effects on agriculture.

Extent of Adoption of Bangladesh Rice Research Institute (Brri) Recommended Boro Rice Varieties

Extent of Adoption of Bangladesh Rice Research Institute (Brri) Recommended Boro Rice Varieties

Manipulation of Chemical Properties in Soil under Wetland Rice through Industrial Effluents

A laboratory experiment was conducted in Soil Science Division of Bangladesh Rice Research Institute (BRRI) during 2010-11 aimed to determine the effects of different industrial effluents on some soil chemical properties under long-term industrial wastewater irrigated rice field. Effluents irrigation created some differences in soil pH, electrical conductivity and organic carbon. The pH in all soil depth was higher with wastewater irrigated rice field. Irrigation with wastewater increased in all the effluents irrigated rice fields; the electrical conductivity (EC) was remarkable higher with all soil depth than the control field. In all the rice fields soil (Control + effluents irrigated fields), the organic carbon content (%) started to decrease sharply with the increase in soil depth. Organic carbon content was slightly higher with wastewater irrigated rice soils. Exchangeable cations (Ca, Mg, K and Na), trace elements (Zn, Fe, Mn and Cu) and heavy metals (Pb, Cd, Cr and Ni) were increased through irrigation with wastewater in rice–rice cropping pattern.

Identifying Climatic Variables with Rice Yield Relationship and Land Cover Change Detection at Sylhet Region

The study is conducted to determine the correlation between climatic parameters and rice yield. The present study is also undertaken to analyze the land cover change in Sylhet district between 2013 and 2018 using LANDSAT-8 images. Local climate and rice yield data are collected from BMD (Bangladesh Meteorological Department) and BRRI (Bangladesh Rice Research Institute) and BBS (Bangladesh Bureau of Statistics). ArcGIS 10.5 and SPSS software are used to show the vegetation condition and correlation coefficient between rice yield and climatic variables respectively. It is revealed from the result that rainfall is negatively correlated with Aman and Boro (local and HYV) rice whereas temperature and relative humidity showed a positive correlation with local Aman and Boro rice. On the other hand, relative humidity showed a strong linear relationship with HYV Boro rice. Finally, both temperature and relative humidity have substantial effects on yields in the Boro rice. Furthermore, vegetation condition is observed through NDVI and found the moderate-high vegetation in 2013. After that NDVI value is fluctuating which evidently signifies the rapid vegetation cover change due to a flash flood, flood and other climate changing aspects. Additionally, Forested and high land vegetation’s are endangered rapidly. Some adaptation strategies should be followed to minimize the effects of natural calamities for improving better vegetation condition.

Effect of Seed Rate on Seedling Quality for Mechanical Rice Transplanting

A study was conducted in the Farm Machinery and Postharvest Technology Division, Bangladesh Rice Research Institute (BRRI), Gazipur in the irrigated dry season (Boro) of 2012-13. It was aimed at identifying the optimum seed rate of different graded rice variety for mat type seedlings preparation and suitable seedling adjustment option of the rice trans planter to maintain required number of seedlings dispensed per stroke by the rotary picker of the trans planter. Walk behind type 4-rows rice trans planter (DP 480) was used to conduct the study. The experiment was followed as two factorial completely randomized design (CRD) with three replications. Three categories of rice variety as short and bold grain (cv. BR3), medium and slender grain (cv. BRRI dhan28) and extra-long and slender grain (cv. BRRI dhan50) were considered as main factor whereas seed rate of 100, 120, 130, 140, 150 and 160g pertray (280×580×25 mm) were considered as sub-factor. Irrespective of rice category, seedling emergence decreased with the increase of seed rate. Seedling emergence decreased from 77 to 56, 74 to 57 and 77 to 54% in BR3, BRRI dhan28 and BRRI dhan29 respectively with the increase of seed rate from 100 to 160g per tray. Seed rate did not affect the seedling height significantly whereas it was varied with the rice verities only and BRRI dhan50 produced higher seedling length. However, number of leaf, stem thickness and shoot dry weight decreased and root-shoot ratio increased significantly with the increase of seed rate. The highest shoot dry weight was observed in BR3 followed by BRRI dhan50. Seedling strength also decreased with the increase of seed rate. The highest seedling strength (0.043 mg cm-1) was observed for the seed rate of 100g of BR3 and the lowest (0.020 mg cm-1) for the seed rate of 160g of BRRI dhan28. The number of seedling increased and percentage of missing hills decreased with the increase of both the seed rate and seedling adjustment option of the rice transplanter irrespective of variety. In case of BR3, seedling dispensed per stroke and percentage of missing hills varied from 4.3 to 5.7 and 6.8 to 7.8 for the seed rates of 140, 150 and 160 g of seeds tray-1 for 5 to 7 seedling adjustment option of the rice transplanter respectively. Seedlings per stroke and percentage of missing hills of BRRI dhan28 for the seed rate of 130, 140 and 150 g of seeds tray-1 was found almost same for 5 to 7 seedling adjustment options of the rice transplanter (4.2 to 6.3 and 5.7 to 9.8). However, there was minimum difference of seedlings per stroke and percentage of missing hills among 120, 130 and 140 g of seeds tray-1 for the option of 4 to 7 (4.0 to 5.6 and 3.9 to 7.8 respectively) for BRRI dhan50. It can be concluded that 140 g of seeds tray-1 for short and bold grain (BR3) and 130 g of seeds tray-1 for medium and slender grain (BRRI dhan28) under the seedling adjustment options of 5 to 7 and 120 g of seeds tray-1 for extra-long and slender grain (BRRI dhan50) under the seedling adjustment options of 4 to 7 may be used for desired seedlings per hill and minimum missing hills along with good quality of seedling.&#x0D; Bangladesh Rice j. 2018, 22(1): 9-23

Weather Condition, Seasonal Variation and Ball Development Pattern in Relation to Rice False Smut Disease in Bangladesh

Rice false smut (RFSm) is an international disease. The effect of the disease has become seriously evident in Bangladesh since 2010. The disease is predominant in the country in the ‘T. Aman’ rice growing season. Its occurrence in other rice growing seasons not well studied and recorded. Information on driving weather variable(s) causing the disease epidemic is scanty and not ground-truthed. This study, conducted in the experimental farm of the Bangladesh Rice Research Institute, Gazipur, Bangladesh, attempted to fill those information gaps. The association of disease incidence and weather parameters such as relative humidity, cloud hour and rainfall, was inconsistence except for the daily average temperature. High disease incidence occurred when the average temperature during panicle emergence period ranged between 22-27°C; any temperature below or above the range linearly decreased the disease incidence. RFSm disease was recorded in the study area in all the months, except for in February and March. The distribution in the incidence of disease in the three rice growing seasons followed the order of ‘T. Aman’ &gt; ‘Aus’ &gt; ‘Boro’; it was ~ six times less in ‘Aus’ and ~ eight times less in ‘Boro’ season, compared to ‘T. Aman’ season. New balls formed on infected panicles in batch by batch. High number of such batches formed in ‘T. Aman’ season. The final status of the disease in an infected crop was the accumulation of incidence of the disease in each batch. This study provided key epidemiology on the development of RFSm in nature and it is concluded such information on the disease under local conditions would be the key to designing management options.&#x0D; Bangladesh Rice j. 2018, 22(1): 57-64

Nutrient Mineralization and Soil Biology as Influenced by Temperature and Fertilizer Management Practices

High soil temperature due to climate change may influence nutrient mineralization and soil biology. An incubation study was conducted at Bangladesh Rice Research Institute to determine the effect of temperature (28°C and 45°C) on nutrient mineralization and soil microbial population of two different soils (terrace and saline soil) having different nutrient management practices (chemical fertilizer and integrated nutrient management). Terrace soil was clay loam and saline (6 ds m-1) soil was sandy loam in texture. Total N and organic C content was significantly high in terrace soil compared to saline soil. High temperature (45°C) enhanced C mineralization by 33% in integrated nutrient management (INM) of terrace soil and 41% in chemical fertilizer treatment in saline soil. The NH4+-N mineralization was increased by 3 fold in saline soil at 45°C as compared to the same at normal temperature of 28°C. Temperature and nutrient management options also significantly influenced phosphorus (P) and potassium (K) mineralization. High temperature significantly enhanced P mineralization in INM compared to chemical fertilizer amendment. In terrace soil, at 28°C temperature K mineralization was high in chemical fertilizer amended soil as compared to INM treatment. Temperature and nutrient sources affected soil bacterial population significantly compared to fungi, and actinomycetes. Phosphate solubilizing bacteria (PSB) were more resistant to high temperature compared to free-living N2 fixing bacteria. In general, high temperature and nutrient management practices affected C, N, P, K mineralization and soil biology; although mode of action varied and depending on soil types and nutrient management practices.

Effect of Missing Nutrient Elements on Grain Yield of Wet Season Rice in Bangladesh

Background and objective: Long-term fertility study is one of the important factors to monitor changes in yield because of different nutrient management options and cropping systems involved in Asian regions. Many short-term and long-term fertilizer trials were conducted for intensive irrigated rice cropping patterns mostly to provide fertilizer rate, but did not considered sustainable soil management for soil health. The objective of the present study was to examine the effect of missing nutrient elements for a long time on rice yield, photosynthetic rate and residual soil fertility. Materials and Methods: The experiment was initiated on a permanent layout at the Bangladesh Rice Research Institute (BRRI) farm, Gazipur during 2000 to 2008 in wet season. Seven treatments in randomized complete block design with four replications were imposed. Grain yield was determined at physiological maturity from three 5 m2 areas within each plot followed by bagging and threshing. Photosynthetic was measure by Li Cor 6400 (USA) machine during study period. Soil sample was analyzed for following standard methods. Results: It was found that grain yield was in decreasing trends for the missing elements that were similar with BR 11 and BRRI dhan 31. On an average, grain yield reductions were 11.6, 7.0, 10.6, 1.1 and 3.4 percent for -N, -P, -K, -S and -Zn, than complete fertilizer treatment (NPKSZn) respectively. Under no fertilization, the ability of soil was to produce 2.9 t·ha-1 of BR11 and 3.1 t·ha-1 of BRRI dhan 31 respectively. Photosynthetic rate of rice plant was always higher in complete fertilizer treatment (NPKSZn) than missing of any nutrient element. The decrease in photosynthetic rate was more pronounced with N missing than others for both the rice varieties. Conclusion: It is concluded that balance chemical fertilizers (NPKSZn) are to be used for sustained and/or increased rice production and to maintain soil fertility.

Effect of Crop Establishment Method and Nutrient Management on Yield and Yield Attributes of Short Duration T. Aman Rice

A field trial was conducted at Agronomy Farm of Bangladesh Rice Research Institute to find out the effect of crop establishment method and nutrient management on yield performance of BRRI developed short-duration Aman rice var. BRRI dhan62 during July to October 2016. The trial comprised of four crop establishment methods viz., M1 = BRRI recommended puddle transplanting, M2 = System of rice intensification (SRI) method (9-days old seedling transplantation), M3 = Sprouted seed in line sowing and M4 = Sprouted seed in broadcasting and three nutrient management levels viz.,N1 = BRRI recommended nutrient management, N2 = Soil test-based nutrient management, N3 = Control. The study was conducted in a factorial Randomized Complete Block Design with three replications. The result showed that planting methods had significant effects on the yield of rice. The SRI method along with BRRI recommended fertilizer dose produced the maximum grain yield of 4.49 t ha-1 which was statistically similar with that produced in SRI method day- and soil test-based nutrient management combination. The highest gross margin (Tk. 36,308.00 ha-1) and cost benefit ratio (2.06) were observed in direct seeding of sprouted seed in line sowing method along with BRRI recommended fertilizer dose. So, direct seeding of sprouted seed in line could be a suitable planting method due to reduction of 26.0% production cost associated with seedling raising and transplanting operations.&#x0D; Bangladesh Agron. J. 2018, 21(1): 117-123

Sensitivity of Annual Weeds Against Metolachlor + Bensulfuron - Methyl Herbicide in Transplanted Rice

&#x0D; Field trials were conducted at Bangladesh Rice Research Institute (BRRI), Gazipur during aman, 2014 and boro, 2014-15 to evaluate the efficacy of metolachlor + bensulfuron methyl 20% WP on weed suppression of transplanted rice. Metolachlor + bensulfuron methyl 20% WP @ 150, 190 and 230 g ha-1 were applied and pyrazosulfuran ethyl @ 125 g ha-1, weed free and unweeded control were the treatment variables. Visual observations indicated that this herbicide possesses high selectivity and not toxic to rice plants. The results revealed that the major weed flora associated with the transplanted rice was mainly comprised of two grasses, two sedges and three broadleaf in aman and two grasses, two sedges and two broadleaf in boro season. The most dominant weeds were Cyperus difformis, Echinochloa crus-galli, Scirpus maritimus and Monochoria vaginalis in both the growing seasons. Application of metolachlor + bensulfuron methyl 20% WP @ 190 g ha-1 was most effective to suppress weeds in both the seasons resulting in increased grain yield more than 40% as compared to unweeded control. Therefore, metolachlor + bensulfuron methyl 20% WP@ 190 g ha-1applied at one to two leaf stage of weed effectively controls the weed infestation in transplanted rice.&#x0D; Bangladesh Agron. J. 2018, 21(1): 61-70&#x0D; &#x0D;

Grain yield, growth response, and water use efficiency of direct wet-seeded rice as affected by nitrogen rates under alternate wetting and drying irrigation system

ABSTRACT The present investigation aimed to determine the effectiveness of different nitrogen (N) rates on grain yield, growth, and water use efficiencies of direct wet-seeded rice and to create a relationship of N rates with growth parameters and dry matter production at different stages. The experiments compared six rates of nitrogen (0, 40,80,120,160, and 200 kg ha–1N) replicated thrice in randomized complete block design in two conjunctive years of 2009–2010 and 2010–2011 at Bangladesh Rice Research Institute farm, Gazipur.The highest grain yield of 7.85 and 7.22 t ha−1 was observed in N200 treatment in 2009–2010 and 2010–2011, respectively. The relationship (R 2) of total dry matter with leaf area index , leaf area duration, and crop growth rate indicated strong association during booting stage to achieved maximum dry matter during harvest. Water use efficiency varied 87–91% in different N levels.

Effect of growing media on mat type seedling raised for mechanical rice transplanting

Mechanical transplanted seedling must meet the requirements of standard seedling block with uniform distribution of seedlings and inter-twisting roots for rolling. This study was conducted to identify the effect of growing media on mat type seedling raised for mechanical transplanting at Bangladesh Rice Research Institute (BRRI), Gazipur during the period of 2012–2014 covering two dry and cold seasons (Boro) and one wet season (Aman). Seedling were raised on plastic tray using sandy loam and clay loam soil mixed with decomposed cow-dung, mustard cake, rice straw organic fertilizer, rice bran, poultry litter and vermicompost at the rate of 0.0, 10, 20, 30 and 40%. Rolling quality of the seedling mat decreased and seedling height increased with the increased of mixing rate of organic fertilizer except rice bran and mustard cake. Averaged across three seasons, 10 to 30% cow-dung, rice straw organic fertilizer, vermicompost, 10% poultry litter and 20 to 30% rice bran with both types of soil was found suitable for seedling mat and seedling height. However, seedling varied among the organic fertilizers with both types of soil in the order of cow-dung &amp;gt; rice bran &amp;gt; vermicompost &amp;gt; poultry liter &amp;gt; rice straw organic fertilizer &amp;gt; mustard cake. Clay loam soil showed better performance on rolling quality over sandy loam soil.

Genetic variability and character association of quantitative traits in jhum rice genotypes

Thirty jhum rice genotypes of hilly origin were studied for genetic variability, correlation and path analysis under medium high land of Bangladesh Rice Research Institute, Gazipur, Bangladesh. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications for the period of March to July (Aus season), 2016. Analysis of variance revealed significant difference among the genotypes for all the characters studied. The PCV values were greater than GCV, revealing little influence of environment in character expression. High values of heritability along with high genetic advance were observed for filled grain and plant height. Such outcomes suggested predominance of additive gene action in gene expression for these characters. Grain yield showed positive association with number of effective tiller and thousand grain weight at genotypic in conjunction with phenotypic level. Most of the traits had significant genetic variability besides, plant height and panicle length exhibited positive direct effect together with positive correlation with yield. Thousand grain weight possessed negative direct effect but highest positive significant correlation with yield.SAARC J. Agri., 16(1): 193-203 (2018)

Relationship between precipitation and rice production in Rangpur district

An experiment was carried out to reveal the precipitation pattern and to find out the interrelationship between precipitation and production of rice in Rangpur district. Rangpur division is more favorable for rice production. Monthly and yearly precipitation data (1983-2013) were collected from Bangladesh Meteorological department (BMD), Agargaon, Dhaka; Bangladesh Agricultural Research Council (BARC), Farmgate, Dhaka and rice production data were collected from Bangladesh Rice research Institute (BRRI); Department of Agricultural Extension (DAE), Rangpur, Bangladesh. From the analyzed precipitation data, it was clearly found that in 1984, 1985, 1987, 1999 and 2005, there were heavy precipitations and resulting flash flood. The average precipitation of Rangpur was higher (1344 mm) in 1987 than 1984, 1985, 1999 and 2005. In Rangpur district, rice production was the highest in the year of 1983, 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1995, 1996, 1997, 1998, 2001, 2002, 2003, 2004, 2007, 2008, 2009, 2010, 2011, 2012 and 2013 and lower in the year of 1984, 1985, 1987, 1994, 1999, 2000, 2005, and 2006 on the basis of total annual precipitation. Rice production reduced main two reasons such as, heavy precipitation causes flash flood and lower precipitation causes drought stress condition. Both are threat-full for higher rice production. The results show that more precipitation in the years of lowest rice production period, heavy precipitation responsible for deduction of rice production area because of flooding and drought and also shows that normal/ minimum precipitation favorable for rice production at Rangpur district. From this study, it is concluded that the irregular precipitation of period (1984, 1985, 1987, 1994, 1999, 2000, 2005, and 2006) was not satisfactory for rice production due to heavy and/or excessive lower precipitation that resulting flood and/or in part of Rangpur district of Bangladesh. The analysis exposed that precipitation was one of the most important factors for higher amount of rice production in Rangpur district.Progressive Agriculture 29 (1): 10-21, 2018