Aus Rice Research Articles

Profitability and productivity of drought tolerant Aus rice variety Binadhan-19 in some areas of Bangladesh

The present study was conducted in five districts namely Mymensingh, Ranpur, Pabna, Rajshahi and Chapainwabganj in Bangladesh. The objectives of the study were i) to identify the socio-economic characteristics of Aus rice growers; ii) to estimate profitability and productivity of Binadhan-19 in the study areas; and iii) to find out the major preferences and constraints for the variety cultivation. A total of 200 farmers were randomly selected (40 from each location) to collect the data with a pre-designed questionnaire. The distribution of the farmers by age showed that the mean age for Binadhan-19 cultivated farmers was 43 years. In the study areas among the farmer 86% was educated. Farmers average experience was 20 year and income were Tk. 235066 (USD 2611.84) per year. Per hectare average yield of rice was 1.37 ton. It was estimated that, to produce one kilogram of rice, total cost incurred was Tk. 14 where per kg average selling price of rice was Tk. 17. The average gross return and gross margin of rice cultivation were found Tk. 90679 (USD 1007.54)/ha and Tk. 51290 (USD 559.88)/ha, respectively. Per hectare average net return was Tk. 2459 (USD 27.32) which was found to be highest in Chapainwabganj Tk. 29739 (USD 330.43) and lowest in Rangpur Tk. 12692 (USD 141.02) district. BCR on total cost basis was found 1.37. The highest preference was for neat rice 98% and the highest constrain said by the farmer was crop destroy by animal and bird of paddy for early ripening in Binadhan-19 cultivation.

Impact of vermicompost based nitrogen management and plant spacing on the performance of short duration transplant Aus rice (cv. Parija)

An investigation was carried out at the Agronomy Field Laboratory, Bangladesh Agricultural University to inspect the effect of vermicompost based nitrogen management and plant spacing on the yield performance of short duration transplant Aus rice (cv. Parija). The study comprised three spacing viz. 20 cm × 20 cm, 20 cm × 15 cm and 20 cm × 10 cm, and five nitrogen management viz. no nitrogen, 75 kg N ha-1, 55 kg N ha-1 + vermicompost @1.25 t ha-1, 35 kg N ha-1 + vermicompost @2.5 t ha-1 and vermicompost @5 t ha-1. The experiment was laid out in a Randomized Complete Block Design with three replications. At harvest, both the spacing of 20 cm × 20 cm and 20 cm × 15 cm produced the tallest plants, the highest number of total tillers hill-1 and effective tillers hill-1. The highest grain yield (3.59 t ha-1) was recorded in 20 cm × 15 cm spacing which was at par with the grain yield (3.52 t ha-1) in 20 cm × 10 cm spacing. The 20 cm × 10 cm spacing also produced the highest straw yield (4.88 t ha-1) and biological yield (8.40 t ha-1). The lowest grain, straw and biological yields were recorded at the wider spacing of 20 cm × 20 cm. In contrast, the highest grain yield (3.79 t ha-1), straw yield (4.99 t ha-1) and biological yield (8.79 t ha-1) were found in 75 kg N ha-1 which was as good as the yields of 55 kg N ha-1 N+ vermicompost @1.25 t ha-1. The highest number of total tillers hill-1 (14.11) and effective tillers hill-1 (12.67) were found in the interaction effect of 20 cm × 20 cm spacing with 75 kg N ha-1. The interaction between 20 cm × 15 cm and 55 kg N ha-1 N+ vermicompost @1.25 t ha-1 gave the highest grain yield (4.58 t ha-1), straw yield (5.71 t ha-1) and biological yield (10.29 t ha-1). The lowest grain yield (2.03 t ha-1), straw yield (3.49 t ha-1) and biological yield (5.52 t ha-1) were found in the interaction between 20 cm × 20 cm and no nitrogen. Therefore, usage of 20 cm × 15 cm spacing fertilized with 55 kg N ha-1 + vermicompost @1.25 t ha-1 appeared as the promising practice of transplant Aus rice cv. (Parija) cultivation.

Performance of Transplant Aus Rice Varieties under Different Nitrogen Management Practices

Management of applied nitrogen in rice field is one tool that could lead to increase in rice yield, but often ignored by most farmers. The experiment was carried out from April to July 2015 at the Agronomy Field Laboratory of Patuakhali Science and Technology University, Dumki, Patuakhali to find out the influence of different nitrogen management and variety on the yield performance of transplant Ausrice. The study consisted of four levels of nitrogen viz. Control (without N), 30 kg N ha-1, 60 kg N ha-1 and urea super granule @ 52 kg N ha-1 and four Transplanted aus rice varieties viz. KaliHitta, ChaitaBoro, Abdul Hai and Gota IRRI, and was laid out in a split-plot design with three replications. The levels of nitrogen were assigned in the main plot and varieties were allocated in the sub-plots. Nitrogen management, variety and their interactions exerted significant (P ≤ 0.05) influence on plant characters, yield contributing characters and yield of transplanted Aus rice. In the case of nitrogen management, the tallest plant was 161.60 cm, maximum leaf area index(2.97, the highest number of effective tillers hill-115, longest panicle 24.30 cm with the maximum number of filled grains as94.73, 1000-grain weight gave 29.97 g. Grain yield of 2.48 t ha-1 were obtained from USG @ 52 kg N ha-1 and the shortest plant height of 136.90 cm with lowest leaf area index of 1.78, lowest number of effective tillers hill-1 (8.43), shortest panicle (18.84 cm) with the lowest numbers of filled grains panicle-1 (53.18), 1000-grain weight (24.33 g) and grain yield (1.40 t ha-1) were obtained in control (N1=O, kg N ha-1). Among the varieties, ChaitaBoro gave the tallest plant height (151.60 cm) and maximum leaf area index (2.54). While the highest number of effective tillers hill-1 (12.20), longest panicle (22.42 cm) with the maximum number of filled grains panicle-1 (73.50), highest 1000-grain weight (27.41 g) and highest grain yield (2.39 t ha-1) were recorded from Gota IRRI than other varieties. In case of interaction, Gota IRRI Fertilized with USG at 52 kg N ha-1 produced the highest number of effective tillers hill-1 (16.87), panicle length (25.13 cm), number of grains panicle-1 (105.70) and grain yield (3.13 t ha-1). The lowest number of effective tillers hill-1 (8.13), lowest panicle length (17.47 cm) with minimum numbers of filled grains 47.67) and grain yield (1.12 t ha-1) were produced by the interaction of control (N1=O, kg N ha-1) and Kali Hitta. So, cultivation of transplant Aus rice (Gota IRRI) appeared to be the best performance with USG @ 52 kg N ha-1 and recommended to the end users.

Impact of seasonal climatic variability on rice yield in Bangladesh


 In Bangladesh, 75% of the total cultivable area is under rice cultivation producing 25 million tons of rice and plays a vital role in the country’s GDP. The climatic variability is playing an important role in affecting the rice production. In this study, the impact of climatic variability (average maximum temperature (aMaxTemp), average minimum temperature (aMinTemp) and average rainfall (aRainfall)) on rice yield was determined in two different regions (northern and southern) of Bangladesh.The variability of rice yield and climate factors was determined by using the Ordinary Least Square (OLS) method. The data was analyzed over the 44-years period (1971 to 2014) in order to estimate the magnitude of these fluctuations statistically and graphically. We observed that the climate variables had significant effect on rice yield that varies among three rice crops (e.g., Aus, Aman, and Boro rice). We observed that, aMaxTemp has positive effects for Aus and Aman rice yield but negative effect on Boro rice yield. On the other hand, aMinTemp has negative effects on Aus and Aman rice yield but has positive effect on Boro rice yield. The aRainfall has a positive relationship with all rice yields in both the regions.

Management and Utilization Strategy of Water Resources for Rice Production

Declination of available water resources is threatening the dry season crop production in Bangladesh. Sustainable water management is crucial need to meet future food production. This study was aimed to determine futuristic water management strategy for rice cultivation. Both surface and groundwater is getting scarce in north-west region, whereas abundant of fresh surface water creating opportunities to irrigate dry season crops in south-central region. This study has outlined irrigation management for rice cultivation and groundwater utilization in water scarce area of north-west region. More than 75% of annual rainfall occurred during monsoon and crops other than monsoon often faced water shortage. Timely establishment of T. Aus rice on 01 May accounted average 183 mm supplemental irrigation for north-west and south-west region. Transplanting of T. Aman rice before 24 July found the low risk period of drought and gave about 1 t ha-1 yield advantage than late transplanting after 15 October. Supplemental irrigation in drought year gave up to 26% yield advantage than the rain-fed condition of T. Aman rice in experimental plot. Over exploitation of groundwater by famers for crop cultivation makes the groundwater status worsen. Farmers used 38% excess water than the actual requirement for Boro rice cultivation. For that annual groundwater withdrawal was higher than annual recharge causing groundwater level depletion in most of the districts. Groundwater table went below suction limit of shallow tubewell (STW) during dry season and thus it become unable to operate. Improved distribution system with plastic pipe, buried pipe could save about 25% of irrigation water. Alternate wetting and drying (AWD) irrigation method saved 20-25% water than farmer’s practice. Application of these on-farm water management technologies in Boro rice reduced water demand and made the groundwater balance positive as well as reduced the groundwater withdrawal pressure. On the contrary, irrigation with less saline surface water resources in river and canals of south central regions could expand Boro production and increased land productivity. Intervention of low lift pump with plastic pipe distribution in non-saline tidal areas could increase land productivity. Besides, trapped freshwater in to the canals inside the polders and re-excavation of these canals would make crop intensification. Thus, additional food production could help to achieve sustainable development goal and sustained food security. Bangladesh Rice J. 25 (1) : 37-50, 2021

Rice yield responses in Bangladesh to large-scale atmospheric oscillation using multifactorial model

This paper intends to explore rice yield fluctuations to large-scale atmospheric circulation indices (LACIs) in Bangladesh. The annual dataset of climate-derived yield index (CDYI), estimated using principal component analysis of Aus rice yield data of 23 districts, and five LACIs for the period 1980–2017 were used for this purpose. The key outcomes of the study were as follows: three sub-regions of Bangladesh, northern, northwestern, and northeastern, showed different kinds of CDYI anomalies. The CDYI time series in north and northeastern regions exhibited a substantial 6-year fluctuation, whereas a 2.75- to 3-year fluctuation predominated the northwestern region. Rice yield showed the highest sensitivity of LACIs in the northern region. Indian Ocean dipole (IOD) and East Central Tropical Pacific SST (Nino 3.4) in July and IOD index in March provide the best yield prediction signals for northern, northwestern, and northeastern regions. Wavelet coherence study demonstrated significant in-phase and out-phases coherences between vital climatic variables (KCVs) and CDYI anomalies at various time-frequencies in three sub-regions. The random forest (RF) model revealed the IOD as the crucial contributing factor of rice yield fluctuations in the country. The multifactorial model with different LACIs and year as predictors can predict rice yield, with the mean relative error (MRE) in the range of 4.82 to 5.78% only. The generated knowledge can be used to early assess rice yield and recommend policy directives to ensure food security.

Evaluating the impacts of major cyclonic catastrophes in coastal Bangladesh using geospatial techniques

Cyclonic catastrophes frequently devastate coastal regions of Bangladesh that host around 35 million people which represents two-thirds of the total population. They have caused many problems like agricultural crop loss, forest degradation, damage to built-up areas, river and shoreline changes that are linked to people’s livelihood and ecological biodiversity. There is an absence of a comprehensive assessment of the major cyclonic disasters of Bangladesh that integrates geospatial technologies in a single study. This study aims to integrate geospatial technologies with major disasters and compares them, which has not been tried before. This paper tried to identify impacts that occurred in the coastal region by major catastrophic events at a vast level using different geospatial technologies. It focuses to identify the impacts of major catastrophic events on livelihood and food production as well as compare the impacts and intensity of different disasters. Furthermore, it compared the losses among several districts and for that previous and post-satellite images of disasters that occurred in 1988, 1991, 2007, 2009, 2019 were used. Classification technique like machine learning algorithm was done in pre- to post-disaster images. For quantifying change in the indication of different factors, indices including NDVI, NDWI, NDBI were developed. “Change vector analysis” equation was performed in bands of the images of pre- and post-disaster to identify the magnitude of change. Also, crop production variance was analyzed to detect impacts on crop production. Furthermore, the changes in shallow to deep water were analyzed. There is a notable change in shallow to deep water bodies after each disaster in Satkhira and Bhola district but subtle changes in Khulna and Bagerhat districts. Change vector analysis revealed greater intensity in Bhola in 1988 and Satkhira in 1991. Furthermore, over the years 2007 and 2009 it showed medium and deep intense areas all over the region. A sharp decrease in Aus rice production is witnessed in Barishal in 2007 when cyclone “Sidr” was stricken. The declination of potato production is seen in Khulna district after the 1988 cyclone. A huge change in the land-use classes from classified images like water body, Pasture land in 1988 and water body, forest in 1991 is marked out. Besides, a clear variation in the settlement was observed from the classified images. This study explores the necessity of using more geospatial technologies in disastrous impacts assessment around the world in the context of Bangladesh and, also, emphasizes taking effective, proper and sustainable disaster management and mitigation measures to counter future disastrous impacts.

Effects of Prilled Urea, Urea Briquettes and NPK Briquettes on the Growth, Yield and Nitrogen use Efficiency of BRRI Dhan48

Nitrogen is one of the most deficient plant nutrients in Bangladesh soils. The use nitrogenous fertilizer especially urea is a commonly used fertilizer for rice production but its efficiency very low about 30-40% under traditional broadcast method A field experiment was carried out in the Soil Science Field Laboratory of Bangladesh Agricultural University, Mymensingh during Aus rice growing season of 2014 to investigate the effects of prilled urea, urea briquettes and NPK briquettes on the growth, yield, and nitrogen use efficiency of BRRI dhan48. There were six treatments as T1 [check (N0P16K42], T2 [Urea briquette (one-3.4 g) (N52P16K42)], T3 (Urea briquette (one-2.7 g (N78P16K42)], T4 [NPK briquette (one-3.4g)(N51P13K32], T5 [Prilled urea (N78P16K42)] and T6 [NPK briquettes(two-2.4 g briquettes (N78P15K42)]. The experiment was laid out in a Randomized Complete Block Design (RCBD) with six treatments and four replications. Prilled urea was applied in two equal splits application; at 8 days after transplanting (DAT) and the second dose after 38 DAT, while for urea briquettes and NPK briquettes were deep placed (8-10 cm depth) at 8 DAT between four hills at alternate rows. Water samples were collected for every 7 consecutive days and analyzed for NH4-N. The results showed that the NH4-N concentration in floodwater reached to maximum on day 2 in PU treated plots and then decreased with time, while the urea briquettes and NPK briquettes treated plots slowly produced NH4-N over the growth period. The highest grain yield of 4.75 t ha-1 (69% over control) was obtained in the treatment T3 [Urea briquette (one-2.7g) (N78P16K42)]. The treatment T3 also produced the highest straw yield of 5.49 t ha-1. The maximum apparent N recovery and the maximum N use efficiency were found in the treatment T4 [NPK briquette (one-3.4g) (N51P13K32)]. It appeared that the deep placement of urea briquettes and NPK briquettes reduced N-losses and enhanced the recovery of applied N as well as N use efficiency in comparison with PU application.

Crop Diversification in Rice—Based Cropping Systems Improves the System Productivity, Profitability and Sustainability

Cropping systems in the Level Barind Tract (LBT) of Bangladesh are highly diverse, as Transplanted (T.) Aman and Boro (T. Boro) rice are a common practice in the area. Although. T. Aman is generally cultivated in the rainy (monsoon) season, but the T. Boro rice is the intensive irrigation-based winter rice with high establishment costs as a result of exhaustive tillage and high labours for transplanting of seedlings. Furthermore, pumping of a large amount of irrigation during T. Boro cultivation declines the level of groundwater, which is not environmentally friendly nor cost-effective. Therefore, the replacement of the T. Boro rice from the cropping pattern in the LBT area is the major concern of policymakers. In this context, a replicated three to four crop-based cropping systems (CS) field trial was conducted in LBT of Gaibandha, Bangladesh for consecutive three years (2018–2020) to evaluate productivity, profitability and sustainability of the multiple crop-based cropping systems. Among these CS, existing three crops based CS, CS1: T. Aman–Potato–T. Boro (introduction of the local potato in the existing cropping system) were compared with four crops based CS2: T. Aman–Potato–Cucumber–T. Aus (Introduction of high yielding potato, cucumber and T. Aus as an improved cropping system). After two years of observations, significantly higher system productivity (rice equivalent yield; REY) was found in the improved CS2 than that of existing CS1 in both years (two years’ average 49% or 11.1 t ha−1). As a result of the introduction of the high yielding potato, cucumber and T. Aus rice instead of the T. Boro rice. The CS2 was also found profitable as compared to the CS1 in terms of higher gross margin (by 74%), net return (double) and benefit-cost ratio (BCR) (1.69 vs. 1.44) due to higher gross return with slightly higher (by 28%) production cost. It is due to farmers received higher prices for potato, cucumber and two rice crops in the improved CS2 than the existing CS1. On the other hand, protein and energy output was lower (by 17% and 9%, respectively) in the CS2 than the existing CS1, due to the less content of protein and energy value in the vegetable cucumber. The results of the study revealed that crops diversification in the existing T. Boro based CS with high yielding potato, cucumber, and T. Aus rice, improved the system productivity, profitability and sustainability; which lead to improve the food security of the increasing population and also reduce the adverse effect on the environment.

Effect of different age of seedlings on the growth and yield performance of transplanted Aus rice variety

An experiment was conducted in the Agriculture Field Laboratory, Noakhali Science and Technology University (NSTU) to evaluate the effects of age of seedlings on the yield and growth performance of transplanted Aus (T. Aus) rice variety from April 2019 to July 2019. The experiment was carried out assigning four age of seedlings (T1 = 22-day old, T2 = 24-day old, T3 = 27-day old, T4 = 30-day old) and two rice varieties (V1 = BRRI dhan83, V2 = BRRI dhan65). The experiment was laid out in a Randomized Complete Block Design with three replications. In case of variety, the highest plant height (102.108 cm), the highest grain yield (2.643 t/ha), and the highest harvest index (32.317%) were obtained in BRRI dhan83 where the lowest plant height (87.804 cm), the lowest grain yield (2.431 t/ha) and the lowest harvest index (32.068%) were obtained in BRRRI dhan65. The age of seedlings had significantly affected total tillers/hill, effective tillers/hill, panicle length in T. Aus rice variety. The highest plant height (98.16 cm), straw yield (6.122 t/ha), the maximum number of effective tillers/hill (15.347) were obtained in 24 days old seedlings. The highest grain yield (2.634 t/ha) was obtained from 27 days old seedlings, and the highest harvest index (33.88%) was obtained from 22 days old seedlings. The lowest grain yield (2.429) was obtained from 24 days old seedlings, and the lowest panicle length (13.753 cm), harvest index (30.467%), and the minimum number of effective tillers/hill (13.753) were obtained from 30 days old seedlings. The lowest straw yield (5.075 t/ha) and plant height (93.16 cm) were obtained from 22 days old seedlings. In case of interaction, the highest plant height (104.667 cm) and the harvest index (34.86%) were observed in BRRI dhan83 at 27 days old seedlings. The highest straw yield (5.805 t/ha) was observed in BRRI dhan65 at 30 days old seedlings. The maximum number of effective tillers/hill (18.519) was observed in BRRI dhan83 at 24 days old seedlings. The highest grain yield (2.94 t/ha) was observed in BRRI dhan83 at 22 days old seedlings. The lowest plant height (80.67 cm) was observed in BRRI dhan65 at 27 days old seedlings. The minimum number of total tillers/hill (17.01) was observed in BRRI dhan83 at 22 days old seedlings; lowest panicle length (20.78 cm), the minimum number of grains/panicle (68.07) were observed in BRRI dhan65 at 24 days old seedlings; 1000 grains weight (22.76 g), the lowest grain yield (2.18 t/ha) were observed in BRRI dhan83 at 24 days old seedlings; the lowest straw yield (4.54 t/ha) was observed in BRRI dhan65 at 22 days seedlings old and lowest harvest index (29.09%) were observed in BRRI dhan65 at 30 days old seedlings. Based on the above results, it may be concluded that almost all of the yield and yield contributing characters of T. Aus rice performed best under the interaction between age of seedlings 22 days old seedlings and the variety BRRI dhan85.

Impacts of Climate Factors Influencing Rice Production in Bangladesh

This study aims to study the climate change pattern, assess the situation of climate change, finding the influences of climate change on the production of rice, estimating a model between climate change and rice production in Bangladesh. Ordinary Least Squares (OLS), Generalized Least Squares (GLS), Feasible Generalized Least Squares (FGLS) were used in this study to compare the results. This study included all 64 districts of Bangladesh with a time span from 2011 to 2018. It included panel data of the production of Aus rice, Aman rice, Boro rice as well as HYV of each rice (Aus, Aman, Boro) of 64 districts of Bangladesh for agricultural data, temperature, rainfall and humidity of 64 districts for climate data. This study estimates the stochastic production function formulated by Just and Pope (1978, 1979), which allows the effect of inputs on the mean yield to differ from that on yield variance. The results showed that increased climate variability, climate extremes; in particular, exacerbate risk on Rice production in Bangladesh. Rice yields are sensitive to rainfall extremes, with both deficient and surplus rainfall increasing variability. For 1% increase in annual total rainfall, Mean Yield will decrease by 0.139%, 0.141%, 0.132% in OLS, GLS and FGLS method respectively, if other variables remaining the same. For 1% increase in annual average percentage of humidity, Mean Yield increases by 1.352%, 1.340%, 1.362% in OLS, GLS and FGLS method respectively, if other variables remaining the same. for 1% increase in HYV area, Mean Yield increases by 0.831% in OLS, GLS and FGLS method, if other variables remaining the same. Additionally, climate inputs, non-climate input, high yielding variety seeds are found to increase average yield.

Yield and morpho physical characters of some modern aus rice varieties at Khagrachari

Aus, aman and boro are three rice cultivating seasons in Bangladesh. Among these aus is the least cultivated and grown in comparatively small scale due to prevailing drought and less availability of surface water for irrigation. Modern varieties of aus rice cover a significant area of the country conversely local cultivars cover a small area. Aus rice requires much fewer inputs than aman and boro. Due to continuous declination of groundwater level, nowadays more emphasis is given on the extension of aus cultivation throughout the country. The present field study tested yield and morphological attributes of six developed aus rice varieties viz. Binadhan-14, Binadhan-19, BRRI dhan43, BRRI dhan48, BRRI dhan55 and BRRI dhan65 to characterize yield, maturity and phenological properties. The field trial was set at Satvaiyapara of Khagrachari during 2018 following Randomized Complete Block design with dispersed plots. All data were collected at harvest and analysed statistically by Statistix 10. Findings revealed that statistically highest grain yield was produced from BRRI dhan55 (4.49 t/ha) and BRRI dhan48 (4.48 t/ha); the lowest by BRRI dhan65 (3.06 t/ ha). The yield of Binadhan-19 (4.37 t/ha) and Binadhan-14 (3.87 t/ha) was intermediate. In case of maturity, Binadhan-19 (99.33 days) had the shortest life duration and BRRI dhan48 (113.67 days), the longest. The greater portion of the farmers was keen to grow Binadhan-19 and Binadhan-14 instead of BRRI dhan43 and BRRI dhan48 mainly for its short duration, optimal yield, long and slender quality grain. Binadhan-19 might be a promising aus variety in the Khagrachari hill tracts for gaining favourable yield within a short time. Therefore, further studies are needed in jhum cultivation with local cultivars for more significant comparison and acceptability to the rice farming community.

Interactive Effect of Weeding Regimes, Rice Cultivars, and Seeding Rates Influence the Rice-Weed Competition under Dry Direct-Seeded Condition

Dry direct-seeded rice (Oryza sativa L.), a climate-smart and resource-efficient (labor and water) rice production technology is gaining popularity in many parts of Asian countries; however, weeds are the major constraints for its early establishment and optimum productivity. Chemical weed management is effective, rapid, and also decreases weed management costs in dry direct-seeded rice (DSR) system; however, chemical use for weed management have a negative effect on the environment and also have human health hazards. Therefore, integrated weed management (IWM) is the best option for the sustainability of rice production under the DSR system. Improving competitiveness against weeds, weed-competitive rice cultivars, and high seeding rates were found to be the most promising IWM strategies in DSR. In this context, a field study was conducted to evaluate the weed competitiveness of rice cultivars and seeding rates on the performance of aus rice in dry direct-seeded systems in Bangladesh. Three inbred rice cultivars (CV), namely “BRRI dhan26”, “BRRI dhan48”, and “BRRI dhan55”, and one hybrid cultivar, “Arize” were tested in a seeding rate (SR) of 20, 40, and 80 kg ha−1 under two weeding regimes (WR) of weed-free and partially-weedy. Rice grain yield was strongly affected (p < 0.01) by the interactions of WR, CV, and SR. In weed-free conditions, the yield of all three inbred cultivars was increased up to SR of 40 kg ha−1 and for the hybrid cultivar, up to SR of 20 kg ha−1, and with further increment of SR, there was no yield advantage. Conversely, under partially weedy conditions, the yield of three inbred cultivars increased up to SR of 80 kg ha−1; however, for the hybrid cultivar, this increment was up to SR of 40 kg ha−1 and thereafter, no yield gain. In weedy conditions, the higher SR compensates for the yield losses by increasing the competitiveness of rice with weeds. Across SR, the hybrid cultivar had a significantly (p < 0.01) higher weed competitive index (WCI) than all the inbred cultivars and the highest SR always had a higher WCI.

Origin and evolution of aus type fragrant rice (Oryza sativa L.) : A review

Diversity in wild forms and landraces of a crop in a region is an indicator and the core tenet of determining its centre of origin. Jeypore tract of Odisha with diverse rice forms is considered as the earliest, independent rice domestication region of aus ecotype. The aus group of Asian cultivated rice is a distinct population with unique alleles for biotic and abiotic stress tolerance and high genetic diversity even in its fragrant accessions, detected at the molecular level. Annual wild rice Oryza nivara is considered as the progenitor of aus rice. The aus type fragrant rice is the original crop of Indian sub-continent, domesticated in hill areas by primitive tribes, around 4500 years ago. The Chinese japonica rice which came to India later, inherited chloroplast and nuclear genome from wild aus rice and the resulting hybrids formed the aromatic group. Loss or gain of phenotypic characters is the common feature of evolution. The aus landraces possessing characters such as black hull, red pericarp, poor panicle features, low grain yield, associated with wild rice species have evolved into cultivated forms from the intermediate stages of domestication. Considering the archeological evidences, genetic inferences and correlations of different investigations relating to aus type fragrant rice, Jeypore tract is regarded as the place of origin and evolution of this small but significant group of fragrant rice.

DEVELOPMENT OF ALTERNATE CROPPING PATTERN AGAINST TOMATO-FALLOW- T. AMAN RICE IN MEDIUM HIGH LAND OF DINAJPUR

The experiment was carried out at the research field of Agricultural Research Station, BARI, Dinajpur during Mid December to end of November for two consecutive years (2017-18 and 2018-19) to develop an economically sustainable and profitable cropping pattern over existing pattern. Three alternate cropping patterns Tomato-T. Aus-T. Aman, Tomato-Summer onion-T. Aman, Tomato-Indian Spinach-T. Aman were introduced against the existing cropping pattern Tomato–Fallow–T. Aman rice. The experiment was carried out in RCB design with three replications. The highest REY (35.91 t/ha) was recorded from the cropping pattern Tomato-Indian Spinach-T. Aman followed by Tomato-Summer onion-T. Aman (31.26 t/ha) and Tomato-T. Aus-T. Aman (29.04 t/ha). The lowest REY (24.48 t/ha) was obtained from the cropping pattern Tomato-Fallow-T. Aman (Farmers practice). The gross return and gross margin were higher in the alternate cropping patterns compared to existing cropping pattern due to additional yield of T. Aus rice, Summer Onion and Indian Spinach. Therefore, farmers in Dinajpur region of Bangladesh could follow alternate cropping pattern in their medium high land where lands remain fallow after harvesting of Tomato for higher crop productivity and profitability.

Identification of Ideal Trial Sites and Wide Adaptable T. Aus Rice Genotypes Suitable for Bangladesh

GGE biplot study is an effective tool for many crops including rice to identify mega-environments, ideal trial site and suitable genotypes for general and specific adaptation. An attempt was made to find promising T. Aus rice genotypes having suitable grain quality, better agronomic parameters and ideal test location for T. Aus rice growing areas. In this study, a total of 11 promising genotypes along with two popular cultivars BR26 and BRRI dhan48 were tested across six locations; Cumilla, Gazipur, Rajshahi, Rangpur in T. Aus 2016 and 2017 whereas Habiganj and Kushtia only in T. Aus 2017 season. From GGE biplot study, BRRI RS, Rajshahi (E8) was the most discriminating and ideal location for evaluating T. Aus rice genotypes in Bangladesh condition while BRRI RS, Cumilla 2016 (E1) showed the least discriminating ability and the least representative location. From two years combination data, BR9011-19-1-2 (G6) recorded the highest average grain yield (5.11±0.68 t ha-1) but BR9011-46-2-2 (G2) was the most stable genotype having grain yield (4.97±0.62 t ha-1) and other stable genotypes with above average yield were BR9011-67-4-1 (G5), BR9011-34-3-2 (G1), BRRI dhan48 (G13), BR9039-28-3-2 (G9) and BR9039-9-1-3 (G8) indicated that these genotypes adapted to favourable environments. BR26 (G12) was found highly variable and less stable across the test environments. In addition, agronomic trait (plant height, growth duration) and grain quality traits were also considered for suitability and wider adaptation in T. Aus growing areas in Bangladesh. BR9011-46-2-2 (G2) and BR9011-19-1-2 (G6) were the better genotypes in most of the locations but, considering all of the parameters, the newly developed rice breeding line BR9011-67-4-1 (G5) has been identified as suitable genotype to release as a new variety for sustainable T. Aus rice production in Bangladesh.
 Bangladesh Rice j. 2019, 23(2): 77-85

Global Warming and Sea Level Rising: Impact on Agriculture and Food Security in Southern Coastal Region of Bangladesh

Climatologically, the entire southern coastal belt of Bangladesh is most vulnerable than the other parts of the country due to its spatial geo-morphological settings. Global warming and sea level rise are already observed and predicted to be occurred more with time. These bring real negative consequences on the agricultural production and food security, and livelihood for the people live in the coastal areas. Therefore, the study was conducted to analyze the effect of global warming and sea level rise on the agriculture and food security in southern coastal areas of Bangladesh. Both primary and secondary sources of information were collected. Stakeholder consultation, direct field visits and interview of climate affected people in the coastal region were carried out for collecting information on land-use and cropping patterns and adaptation measures to be taken to boost crop production against global warming and sea level rise. By the middle and end of the twenty first century, global annual mean temperature is predicted to be increased about 1.5oC and 2.5oC, respectively. These projected warming will lead to about 14, 32 and 88 cm sea level rise by 2030, 2050 and 2100, respectively which would cause inundation of about 8, 10 and 16 percent of total land masses in Bangladesh. Most of the coastal parts and associated islands of Khulna and Barisal divisions and western part of Chattagram division lie within one meter from sea level where incursion of saline water is common. It is predicted that these areas will be inundated and unsuitable for crop production due to upcoming sea level rise. The predominant crop in entire coastal belt is transplanted Aman with sporadic occurrences of Aus rice. The land in Boro rice season either loosely occupied by mungbean, grass pea, cowpea, groundnut, soybean, potato, sweet potato, chili etc or remained fallow until the following monsoon. A systemic analysis of all of the cyclones that originated from the Bay of Bengal since 1961 indicated that most devastating cyclones formation occurred from last quarter of April through May and from middle of October to November just prior to the harvest of Boro and Aman crops, respectively. Therefore, Boro and Aman rice harvests are mostly unpredictable every year posing great threat to the food security of the coastal people. These areas are criss-crossed by innumerable water canals or channels especially in Barisal and Khulna divisions which can be utilized for Boro rice cultivation in dry season despite some levels of salinity. Cultivation of salt-tolerant crop varieties could mitigate such hindrances. Introduction of saline tolerant Boro rice in coastal cropping patterns and/or advancing the harvesting times by a fortnight in both Aman and Boro rice seasons to avert cyclonic havoc not only ensure food security but also turn the entire coastal belt into a food surplus region.

Adaptation of Promising Rice Genotypes for Broadcast Aus Season

Rice cultivation in Aus season is eco-friendly and essential for sustainable food security of Bangladesh utilizing rain water rather than extracting underground water. Four rice genotypes (BR6855-3B-12, BR6855-3B-13, BR6848-3B-12 and BR6976-2B-11-1) along with check variety BRRI dhan43 were evaluated at farmers’ field during broadcast Aus season. The objectives were to investigate the adaptability of the rice genotypes and find out promising genotype(s) for Broadcast Aus rice. The experiment was conducted at farmers’ field in eight agro-ecological zones of Bangladesh. Randomized complete block design (RCB) was used with three replications. Standard and uniform management practices were followed for all the locations. Data were taken on grain yield, days to 80% maturity, plant height, panicles m-2, 1000-grain weight, grains panicle-1, spikelet sterility (%), Phenotypic acceptance at vegetative and maturity stage, pest incidence; feedback of farmers and extension personnel. Genotypes, environments and interaction of genotypes by environments had significant effect on grain yield, yield components and agronomic parameters. Analysis of variance indicated that there were significant differences between the check (control) and improved genotypes except the genotype BR6976-2B-11-1 which was similar with the check BRRI dhan43 for all parameters. Correlation analysis was also performed to establish extent of association between yield and major yield components. Grain yield positively and significantly correlated with the agronomic parameters except spikelet sterility. Across the locations, BR6848-3B-12 produced significantly the highest grain yield (4.88 t ha-1) at Feni while the lowest grain yield (1.58 t ha-1) was obtained in BR6976-2B-11-1 followed by BRRI dhan43 (1.64 t ha-1) at Kushtia. BR6848-3B-12 showed yield advantage of 1.0 t ha-1 over the check variety BRRI dhan43 with similar growth duration (104 day). AMMI stability value, yield stability index and GGE Bi-plot model indicated that BR6855-3B-12 is the most adaptable, suitable and stable genotype for broadcast Aus rice across the locations, and finally it is released in 2017 as BRRI dhan83 for broadcast Aus season.
 Bangladesh Rice j. 2019, 23(2): 35-48

Impacts of cyclone and flood on crop and fish production in disaster prone coastal Bhola district of Bangladesh

This study assessed the impact of climate change induced disaster on crops and fisheries production at Bhola Sadar and Monpura upazila of Bhola district, Bangladesh during January to June 2018. The study was gathered primary data from primary observation (PO), questionnaire survey (QS), focus group discussion (FGD), and key informant interview (KII). Secondary data were collected from Upazila Agricultural Office and Upazila Fisheries Office of Bhola Sadar and Manpura upazila and moreover, climatic data were collected from Bangladesh Meteorological Department. Results of the study found that trend analysis indicates overall annual maximum temperature increased for Kharif-I, Kharif-II and Rabi season. Average annual minimum temperature also increased for Kharif-I season but decreased for Kharif-II and Rabi season. Study also found that for all cropping season average relative humidity was increased. Annual average rainfall exhibited decreasing trend for Kharif-I and Rabi season but increased for Kharif-II season in (1990-2019) time period. The Aus, T. Aman, Boro and Mung bean was dominant cropping pattern in Kharif-I, Kharif- II and Rabi season in Bhola district. Overall, Aus rice production in Kharif-I season increased but in 2009, 2013 production was decreased because of cyclone Aila (2009) and Cyclone Mahasen (2013). T. Aman production hampered due to Cyclone Sidr (2007) and flood (2014) in Kharif-II season. In Rabi season Boro rice production lessen because of low rainfall and salinity intrusion. Overall, Mung bean production increase but in 2008 and 2009 production become hampered due to late cultivation because of Cyclone Sidr (2007). Fish production rate increase in Bhola specially Hilsha fish because of non-climatic factor like raid in non-fishing time, banned current net but fish production in pond become diminished due to infrequent natural disaster. Practicing of salt and flood tolerant varieties, floating bed vegetable cultivation, and mixed cropping system (mainly for Rabi season), enhanced expedition activities against catching mother Ilish in prohibition period, dredging in the heart of the river which can eventually reduce vulnerabilities and increase crop and fish production in the Bhola region.
 Int. J. Agril. Res. Innov. Tech. 10(1): 40-55, June 2020

Effect of nitrogen management and seedling raising methods on the productivity of Aus rice under tidal ecosystem of Bangladesh

The low productivity of Aus rice in the tidal ecosystem of Bangladesh is mainly due to the difficulties in nitrogen (N) management under high tidal water along with unavailability of irrigation water during the onset of rice cultivation. Our present study demonstrated how the productivity of Aus rice could be improved using appropriate seedling raising methods and N management practices. The study was laid out in split plot design consisting two factors viz., seedling raising methods (wet seed bed and dry seed bed) and N management practices (six N treatments) in three replications. Results indicated that both the seedling raising methods and N management practices had significant effect on all the yield contributing characters of transplanted Aus rice under tidal condition. Specifically, the combination of seedlings raised in wet seed bed and fertilized with urea super granule (USG) at 10 days after transplanting (DAT) i.e., N3W showed the best values for plant height (110.33cm), number of effective tillers hill-1 (14.60), days required 50% flowering (53.00 DAT), days to maturity (84.33 DAT), panicle length (23.37 cm), number of filled grain panicle-1 (88.13), 1000-grain weight (43.17 g), grain yield (4.62 tha-1), straw yield (6.07 tha-1), biological yield (10.67 tha-1), and harvest index (43.17%). However, in considering the productivity/ grain yield, besides N3W, the whole urea application at land preparation along with wet seed bed (N1W) and USG application along with dry seed bed (N3D) also produced statistically similar results (p<0.01) and thus all these three combinations may be practiced for improving productivity and ensuring horizontal expansion of Aus rice in the tidal ecosystem of Bangladesh.