BRRI Dhan29 Research Articles

On-Farm Evaluation of Production Potential and Economics of Four Crops Based Cropping Pattern

A field experiment was conducted at multi-location testing (MLT) site, Barura under On-Farm Research Division (OFRD), Bangladesh Agricultural Research Institute, Cumilla during 2014-16 to determine the productivity and profitability of cropping patterns, viz. Boro (var. BRRI dhan28)-T.Aus (var. BRRI dhan48)- T. Aman (var. BRRI dhan49)-Fallow (existing cropping pattern) and Boro (var. BRRI dhan28)-T. Aus (var. BRRI dhan48)-T. Aman (var. Binadhan-11)-Mustard (var. BARI Sarisha-14) as improved cropping pattern. The results showed that improved cropping pattern provided higher amount of grain and by-product yield. The highest mean REY (18.08 t ha-1), PE (54.61 kg ha-1 day-1), LUE (90.68 %) and SYI (77.12%) was obtained from improved cropping pattern Boro-T.Aus-T. Aman-Mustard and the lowest (14.30 t ha-1 in 2014-15 and 13.98 t ha-1 in 2015-16) from farmers existing cropping pattern. The highest gross return (Tk. 274800 ha-1 in 2014-15 and Tk. 276600 ha-1 in 2015-16), gross margin (Tk. 113950 ha-1 in 2014-15 and Tk. 106750 ha-1 in 2015-16) and BCR (1.70 in 2014-15 and 1.66 in 2015-16) were obtained from improved four crops based cropping pattern (Boro-T. Aus-T. Aman-Mustard). Two years results showed that four crops could be grown one after another in a sequence in the farmers field of Cumilla region for achieving higher system productivity and economic return. Bangladesh Agron. J. 2021, 24(1): 101-108

Additive Main Effect and Multiplicative Interaction (AMMI) model analysis for yield performances and G×E Interaction in multi environmental trial of aromatic fine rice in Bangladesh

The problem of genotype-environment interaction (G×E) in interpreting multilocus trial analyses and predicting genotype performance can be mitigated by applying Additive Main effect and Multiplicative Interaction (AMMI) model analysis. The model AMMI was used in the present study to determine the effect of genotype, environment, and their interaction, to determine the extent of G×E interaction and to identify the factors contributing to G×E interaction for the best yielding aromatic fine rice genotype grown in four different districts in Bangladesh. Analysis of variance showed that the effect of genotypes, environments, G×E interactions were highly significant for plant height, days to maturity, panicles length, grain yield. Result showed grain yield had highly significant differences for environmental traits like (soil properties, phenological, genotypes) with their interactions which indicated that environments were different and changeability with the genotypes. Large variations in total P, Fe and rainfall identified as the main cause of the observed interaction. Here, Genotype BRRI Dhan34 had the highest mean grain yield values over four locations, respectively. In AMMI model, among four locations Dinajpur with Nilphamari were the majority responsive environments and Dinajpur was the most adjacent responsive location. Therefore, location Dinajpur with BRRI Dhan34 genotype could be considered as a better combination for higher grain yield among the ten aromatic fine rice genotypes.

Arsenic Accumulation in Rice Grain as Influenced by Water Management: Human Health Risk Assessment

Rice is a staple food for humans and a key source of soil arsenic (As) transfer to the human food chain. As a result, it is critical to develop ways for reducing As accumulation in rice. A pot experiment with seven different water management practices was done to examine the impacts of water management on rice (cv. BRRI dhan28) growth, yield, and As accumulation in rice grain. Any health risk due to As accumulation in rice grain was also determined. The soil used in the experiment was artificially contaminated with As and the source of As was sodium arsenate (Na2HAsO4 7H2O). Water management practices affect different plant growth and yield parameters including filled grains per panicle, unfilled grains per panicle, 1000-grain weight, grain yield and straw yield of rice. The number of filled grains per panicle and 1000-grain weight were found to be at their highest in the T7 (alternate wetting and drying) condition, whereas the number of unfilled grains per panicle was at its lowest in the same treatment. The T7 also demonstrated the highest grain yield (21.08 g/pot) and straw yield (22.02 g/pot), whereas the lowest values were noted in T1 (flooding throughout the growth period). The highest As concentration in rice grain (0.52 mg kg−1) was found in T1 and the lowest As concentration in grain (0.27 mg kg−1) was found in T7. Estimation of the human health risk revealed that the non-carcinogenic risks (HQ > 1) and carcinogenic risks (CR > 1.0 × 10−4) were greatly affected by different water regimes. The rice plant grown under alternate wetting and drying condition (T7) showed the lowest health risks compared to other water management practices. Thus, alternate wetting and drying conditions are a good water management strategy for increasing rice output while reducing arsenic buildup in rice grain.

Coastal and Marine Pollution in Bangladesh: Pathways, Hotspots and Adaptation Strategies

Marine and coastal pollution is a global issue for human health and biodiversity. We have investigated pollution sources, flow patterns, hotspots, challenges, and adaptation policies in Bangladesh. Industries, ship breaking yards, sewage, tourism, and transboundary depositions are the main sources of pollutions. The Ganges, Padma, Jamuna, Brahmaputra and Meghna carry wastes to the Bay of Bengal. Pollution hotspots are Dhaka, Gazipur, Narshingdi, Narayanganj, Chittagong, Khulna, Mongla port and Sylhet city. Textile and dyeing industries discharge 12.7–13.5 million m3 waste waters annually and pollute 20% of fresh water. Ship breaking yards dump about 22.5 tons polychlorinated biphenyls in a year. More than 50% of the marine oil pollution comes from urban activities. Plastic wastes at 3000 t day-1 and tourism are also contributing to the coastal pollution. Effluent releasing standards are not maintained, and thus higher concentrations of heavy metals are found with marine fishes. Use of heavy metal tolerant crops (rice: BRRI dhan47, potato: Cardinal, mustard: Brassica napus, flower: Marigold, vegetables: Cucumber, fibre: Kenaf, and so on), trap cropping, deep placement of fertilizers, integrated rice-fish-duck culture, etc can be adopted in polluted areas. There are laws for environmental issues, but coordination and financial capabilities does not warrant its effectiveness. Necessary steps are to be taken to improve infrastructure to ensure sanitation and benign discharge of industrial effluents. Systematic study on sources, fate and extent of current effluents dumping in water ways need to be assessed for wellbeing of aquatic life and human health.

‘B-M MODEL’ FOR FARMERS’ KNOWLEDGE MANAGEMENT IN INCREASING RICE PRODUCTION

Quantifying knowledge on agriculture can have many benefits to stakeholders. While many knowledge-based systems exist in modern days for farmers’ decision support, specific models are lacking on how knowledge traits can impact on agricultural production systems. This study employed modelling technique, supported by field data, to provide a clear understanding and quantifying how knowledge management in production practices can contribute to rice productivity in the environmentally stressed southwest Bangladesh. This research accounted for ‘Boro’ rice as the target crop and ‘BRRI dhan28’ as the test variety. The ‘B-M Model’ was developed following the principle and procedure from published literature, ‘brainstorming’ and data from field surveys. Three knowledge management traits (KMT) were defined and quantified as the inputs of the model. Those are: self-experience and observation (SEO), extension advisory services (EAS) and accessed information sources (AIS). The yield influencing process (YIP), the intermediate state variable of the model, was deduced by accounting for the two dominant agronomic practices, seedling age for transplanting and triple superphosphate (TSP) application. ‘Knowledge drives farmers’ practice change which in turn influences yield’ was composed as the theoretical framework of the ‘B-M Model’. The model performed strongly against an independently collected field data set. Across the 180 farmers’ data, the average relative rice yield (RRY) predicted by the model (0.705) and observed in the field (0.716) was close (root mean squared deviation (RMSD) = 0.018). The difference between predicted and observed RRY was not statistically different (LSD = 0.03), indicating the model fully captured the field data. A regression of predicted and observed RRY explained 96% variance in observation, further proving the model’s strength in estimating RRY in a wider range of farmers’ rice yield. In a normative analysis, the practicality and usefulness of the model to stakeholders were simulated for the understanding of how much achievable yield could be expected by changing farmers’ knowledge pool (the sum of three KMT) on rice production practices, and at what combination(s) of KMT to be considered at strategic hierarchy to materialize a targeted achievable yield. To the best of the knowledge, a model quantifying rice yield in relation to knowledge management trait does not exist in literature. Upon successful testing under diverse yield scenarios using multiple and sophisticated statistical tools that enhanced the credibility of the model, it is concluded that the model has the potential to be used for identifying quantitative pathways of farmers’ knowledge acquisition for practice change leading to improved productivity of rice in the southwest region of Bangladesh.

Response of Crop Water Requirement and Yield of Irrigated Rice to Elevated Temperature in Bangladesh

In the changing climatic condition, temperature is the most vulnerable parameter and is projecting a trend of increase in the future. Crop growth and development process depend largely on air temperature. This study aims to determine the role of increasing air temperature in yield, crop water requirement (CWR), and other agronomic parameters of irrigated rice. Ceres-rice model associated in the Decision Support System for Agrotechnology Transfer (DSSAT) was used in 15 different locations of Bangladesh. Grain yield, growth duration, and crop water requirement of widely cultivated irrigated rice (Boro rice) variety BRRI dhan28 were analysed in normal temperature and elevated air temperature by 1°C, 2°C, 3°C, and 4°C. The result revealed detrimental effect of elevated temperature on growth duration and grain yield. The estimated highest growth duration reduction of 30 days was found in Moulvibazar for 4°C temperature rise. The grain yield reduction was projected by 0–17%, 16–35%, 31–49%, and 39–61% from the normal condition if the seasonal mean temperature increased by 1°C, 2°C, 3°C, and 4°C, respectively. The country average crop water requirement was found to be 405 mm of which the highest 445 mm and the lowest 358 mm were recorded in Moulvibazar and Chandpur, respectively. The study revealed that the country average rice CWR reduced by 5%, 8%, 12%, and 17% over the normal condition for 1°C, 2°C, 3°C, and 4°C rising temperature, respectively. For 1°C temperature rise, BRRI dhan28 life span shortened by 6.4 days, grain yield reduced by 695 kg, and estimated CWR decreased by 14 mm. The projected declining CWR indicated that irrigated rice will require less irrigation water, but it will cause considerable yield loss under elevated temperature. Though elevated temperature will save huge irrigation water used in country-wide Boro rice cultivation, the crop developers need to introduce new heat-tolerant cultivar to minimize yield loss.

RESPONSES OF FOUR SUBMERGENCE TOLERANT RICE VARIETIES TO DIFFERENT SUBMERGENCE LEVELS

The selections of suitable variety are very crucial for addressing future challenges and sustainably increase rice production in the flood-prone rice-growing environment. To find out the degree of tolerance of different submergence tolerant varieties under different submergence durations we conducted the present research from July to December, 2018. The experiment comprised of two factors namely, factor A, Submergence durations were S0-control (no submergence situation), S1, S2,and S3 allowing submergence up to 10 days after seedling establishment (DAE), submergence up to 15 DAE, and submergence up to 20 DAE, respectively and factor B- Submergence tolerant varieties were Binadhan-11, Binadhan-12, BRRI dhan52, and BRRI dhan79. The experiment was laid out in a split-plot design where submergence durations were assigned to the main plots and varieties were assigned to the subplots with three replications. The highest grain yield (4.09 t ha-1) was obtained from no submergence situation with BRRI dhan52 followed by no submergence with variety Binadhan-11 (3.87 t ha-1), submergence up to 10 days after seedling establishment (3.61 t ha-1), and submergence up to 15 days after seedling establishment (3.35 t ha-1) with variety BRRI dhan52. Among four submergence tolerant varieties, BRRI dhan52 showed better performance.Thus, it may be concluded that submergence up to 10 or 15 days after seedling establishment with variety BRRI dhan52 might be cultivated in flood-affected areas where rice plants remain 10 to 15 days under floodwater.

Screening of rice genotypes for salt tolerance by physiological and biochemical characters

Crop production is unexpectedly hampered by different abiotic stresses. Salinity is one of the leading stresses, which snappishly hampers plant developmental progression. Local rice landraces exhibit noticeable salt tolerance as well as high yield. However, research is scarce about the physio-biochemical responses of local landraces and modern cultivar under saline conditions. Therefore, the present experiment was designed to reveal the physio-biochemical responses of local landraces and modern cultivar under salinity stress. Five landraces (Jotai, Icheburogolghor, Morishal, Chapail, Kumro buro) and two modern cultivars (BR23 and BRRI dhan41) were subjected to 0, 20, 40, 60 and 80 mM NaCl treatment. The effects of salt stress on morphological parameters, proline contents, and activities of antioxidant enzymes were assessed. Salt stress reduces the morphological parameters of all tested cultivars. The Morishal and BRRI dhan41 exhibited higher growth of plant and physiological parameters than other cultivars under the highest salinity. The catalase (CAT) and ascorbate peroxidase (APX), exhibited a significant increase whereas peroxidase (POX) activity significantly declined in all the cultivars under salinity stress. Morishal and BRRI dhan41 showed the highest proline content under the maximum saline condition. These results suggest that the high tolerant landrace and modern cultivars were Morishal and BRRI dhan41 respectively. These results also suggest that Morishal and BRRI dhan41 exhibited high tolerance to salinity by enhancing proline content and antioxidant enzyme activities.

Biochar – A climate smart practice for milling traits and aroma of fragrant rice under drought stress with different time of harvest

A pot experiment was conducted at research area under plastic net house of Sher-e-Bangla Agricultural University, Dhaka-1207 during 2019-20. BRRI dhan50 was used as planting material. The experiment was laid out in 2x2x3 factorial design with five replications and comprised of three factors viz., Factor-1 (Biochar-2 levels): B1 = (Control) 0.0 t ha-1, B2 = 5.0 t ha-1; Factor-2 (Drought stress-2 levels): D1 = At reproductive stage, D2 = At grain filling stage and Factor-3 (Time of harvest-3 levels): H1 = 3 weeks after flowering, H2 = 4 weeks after flowering and H3 = 5 weeks after flowering. Application of biochar @ 5tha-1 along with drought stress imposed at grain filling stage and crop harvested 5 weeks after flowering showed the best result for brown rice yield, head rice recovery, amylose content, protein content, grain aroma and taste of BRRI dhan50. Application of biochar also increased soil organic carbon content. It can be concluded from the present study that, biochar application can help in reducing atmospheric carbon emitted from puddled rice soil in normal field condition under climate smart technology.

Weed control efficacy of combined application of grass pea and mustard crop residues in T. aman rice

Among different methods of weed control, allelopathy could lead to reduced labor costs and increased efficiency, without any adverse effects on the environment. In this regard, an experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh to evaluate the allelopathic potential of grass pea and mustard crop residues on weed suppression and crop performance of transplanted aman rice. The experiment consisted of three cultivars of T. aman rice viz., Binadhan-7, BRRI dhan49 and BR11 and five different level of crop residues such as no use of crop residues, grass pea crop residues @ 2.5 t ha-1, mustard crop residues @ 2.5 t ha-1, combined use of grass pea and mustard crop residues @ 1 t ha-1 of each and hand weeding. All crop residues applied in the experiment suppressed weed growth and inhibition at satisfactory level. The experiment was laid out in a randomized complete block design with three replications. Weed population, weed dry weight and percent inhibition of weed were not significantly influenced by the interaction effect of crop residues (grass pea and mustard) and cultivars. BR11 produced the highest grain and straw yield among the treatment combination. The highest numbers of tillers hill-1, numbers of grains panicle-1, 1000-grain weight, grain yield, straw yield were observed in hand weeding, followed by combined application of grass pea and mustard crop residues @ 1 t ha-1 of each treatment. The highest grain and straw yield (4.81 t ha-1 and 7.65 t ha-1) was observed in hand weeding along with variety BR11 and the second highest (4.19 t ha-1 and 7.36 t ha-1) was obtained from combined use of grass pea and mustard crop residues @ 1 t ha-1 of each. The results of this study indicate that hand weeding followed by combined application of grass pea and mustard crop residues @ 1 t ha-1 of each showed potential activity to suppress weed growth.

Agrobacterium-mediated Genetic Transformation of Rice var. BRRI Dhan 58

Agrobacterium mediated genetic transformation of BRRI Dhan 58 was conducted by using immature embryos following indirect regeneration. High percentage of callus induction at 96.5% was obtained when seeds of BRRI dhan 58 were cultured on modified MS medium supplemented with 2.5 mg/l 2, 4-D under dark condition. The maximum regeneration response was rerecorded when MS was supplemented with 3 mg/l BAP + 0.5 mg/l NAA and 1.0 mg/l Kn. Genetic transformation was performed using A. tumefaciens strain LBA4404 harboring pCAMBIA1301 plasmid carrying the marker genes for β-glucuronidase (GUS) and hygromycin resistance (hptII). Integration of the GUS gene into the genome of the rice plants was confirmed by PCR. The leaf segments of the PCR positive transformed plants showed the expression of GUS. The results of this study would be an effective tool for crop improvement and functional studies of gene on rice plant.
 Plant Tissue Cult. & Biotech. 31(1): 71-80, 2021 (June)

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.

Enhancing Rice Productivity in the Unfavourable Ecosystems of Bangladesh

Rice is cultivated in the three seasons (Aus, Aman, and Boro) across four ecotypes, including irrigat-ed, rainfed upland, rainfed lowland, and deep water in Bangladesh. Rice farming in unfavourable ecosystems is highly exposed to abiotic stresses and extreme weather events (floods, droughts, storm surges, and cyclones), and its performance is frequently affected by the multiple-stresses and extreme weather events. Besides, the increasing demand for rice for the growing population and decreasing scarce resources, including arable land and fresh-water for irrigation aggravated the concern about sustainable rice production systems under future conditions. Thus, the paper aimed to exploit unfa-vourable ecosystems to increase total rice production for meeting future demand. Secondary data were analyzed to achieve the objectives of the study. BR23, BRRI dhan40, BRRI dhan41, BRRI dhan47, BRRI dhan53, BRRI dhan54, BRRI dhan61, BRRI dhan67, BRRI dhan73, BRRI dhan97, BRRI dhan99, BINA dhan-8 and BINA dhan-10 are resilient to salinity. Besides, BRRI dhan56, BRRI dhan57, BRRI dhan66, BRRI dhan71, and BRRI dhan83 are resilient to drought, and BRRI dhan51, BRRI dhan52, BRRI dhan79, BINA dhan11, and BINA dhan-12 are tolerant to submergence. The BR18, BRRI dhan36, BRRI dhan67, and BRRI dhan69 are some-extent resilient to cold. The research has been con-tinuing for developing further stress-tolerant higher yield potential rice cultivars for unfavourable ecosystems. The increased adoption of currently available stress-tolerant rice cultivars has the poten-tial to give a substantially higher yield than that of locally popular rice cultivars in the unfavourable ecosystems. Therefore, the dissemination of stress-tolerant cultivars to 75% of total rice cropping are-as of saline (0.37 Mha), submergence (1.08 Mha), and drought (2.94 Mha) ecosystem may contribute to increasing rice production in the ecosystems by 1.26 MT, 3.45 MT, and 9.18 MT, respectively. Re-sulting from that 13.89 MT rice will be added to the national rice basket in 2050. The policy supports are needed to strengthen for developing and rapid dissemination of the stress-tolerant cultivars in the unfavourable ecosystems for meeting the increased demand of rice of the growing population under future conditions. Bangladesh Rice J. 24 (2): 83-102, 2021

Performance of Binadhan-17 With Binadhan-18 and Brri Dhan-29 as Affected by Different Planting Time in Magura District of Bangladesh

The experiment was carried out during the period of December to May 2019 at the BINA substation Magura farm and farmers’ field sottopur, sadar, Magura in a randomized complete block design with three replications. The experiment was conducted to study the effect of planting time on the yield and yield attributes along with three sowing time viz. 15 December, 25 December, 05 January and transplanting was done on 24 Jan.; 03 Feb.; 13 Feb. in the main field along with three varieties viz. Binadhan -17, Binadhan-18, BRRIdhan-29. From on farm trial, it revealed that; The transplanting time of February 03 have found more yield and duration (7.62t/ha and 142 days) and transplanting time of January 24 have found have yield and duration 7.59 t/ha and 147 days which was statistically same; lowest yield found in February 13 that was 6.89t/ha and duration 136 days. From on station trial, it revealed that; the January 24 transplanting date was found more yield and duration (7.28t/ha and 147days) and February 03 was found (6.06t/ha and 142 days); lowest yield was found in February 13 transplanting date that was (4.5t/ha and 136 days). From both results discussion, it concluded that Transplanting at January 24 would be the optimum time along with different planting time of Binadhan-17 in Maguraregion.
 Res. Agric., Livest. Fish.8(1): 19-24, April 2021

Seed priming for increased seed germination and enhanced seedling vigor of winter rice

Low seed emergence rate, poor seedling growth and low survival rate of winter rice due to cold spell are very common in Bangladesh. Pre-sowing seed priming could be a viable approach to overcome this problem. A laboratory screening of different priming agents was conducted at the Agro Innovation Laboratory, Department of Agronomy, Bangladesh Agricultural University in November 2018. The experiment comprised two factors. Factor A includes five rice varieties, namely i) BRRI dhan28 ii) BRRI dhan29 iii) BRRI dhan36 iv) BRRI dhan55 and v) Hybrid SL-8H; factor B includes 22 seed priming methods comprised different concentrations of NaCl, KCl CaCl2, CuSO4, ZnSO4, Na2MoO4, PEG and control (no priming). The experiment was laid out in a completely randomized design (CRD) with four replications. A positive influence of seed priming on seed emergence rate (%), germination time, seedling vigor and seedling growth (length and dry matter) was evident from this study. Among the priming agents, KCl and CaCl2 performed best; while priming with NaCl, Na2MoO4 and PEG showed no advantages over no priming for germination rate and seedling vigor & growth indices. In conclusion, pre sowing seed priming approach can be explored as a viable tool for increased seed germination and better seedling growth of winter rice under stress condition.

Genetic Divergence of Rice Genotypes Revealed by Bacterial Blight Disease and Morphological Traits

Bacterial blight is a perilous impediment for rice production. Resistant variety is a sustainable approach to fend off the loss of rice due to bacterial blight disease. In this study, 94 genotypes were screened against bacterial blight disease and its morphological diversity was assessed to find out the resistant donor with desirable morphological characters. Bacterial blight pathogen was inoculated following leaf clipping method for disease scoring. Out of 94 genotypes, 12 showed a resistant reaction, 13 showed moderately resistant reaction and 69 genotypes showed a susceptible reaction. Positive correlation was recorded between yield and most of the morphological characters. Yield hill─1 was significantly correlated with the number of tiller hill─1 (0.503**), number of effective tiller hill─1 (0.538**), total number of spikelets panicle─1 (0.595**), number of filled grain panicle─1 (0.595**), number of unfilled spikelet panicle─1 (0.239*) and 1000 grain weight hill─1 (0.843**). Eleven quantitative characters grouped 94 rice genotypes in 16 clusters at coefficient 3.38 and it indicated the presence of great amount diversity among the genotypes. Principal component analysis (PCA) supported the cluster analysis and the first four principal components explained around 70.99% of total divergence for all morphological characters. Principal coordinate analysis (PCoA) demonstrated that the genotypes BR8862-29-1-5-1-3, SVIN301, SVIN321, BR9207-45-2-2, SVIN018, lRBB5, SVIN038, BRRI dhan28 and BRRI dhan29 were placed in distant position from the centroid and it indicated that they were more diverse than the genotypes near the centroid. However, based on disease reaction and genetic diversity analysis crossing could be made between, resistant genotypes such as SVIN317, SVIN017, SVIN316, SVIN313, SVIN315, SVIN314, SVIN038, SVIN307, SVIN302, SVIN304 with the susceptible variety more specifically with BRRI dhan28, BRRI dhan29, BRRI dhan50, BRRI dhan58, BRRI dhan63, BRRI dhan74, BRRI dhan81 and BRRI dhan84 to develop bacterial blight resistant variety.
 Bangladesh Rice J. 24 (1): 73-84, 2020

Elucidation of Genotype × Environment Interaction for Identification of Stable Genotypes to Grain Yield of Rice (Oryza sativa L.) Varieties in Bangladesh Rainfed Condition

The research was evaluated in seven ecological zones throughout the country following randomized complete block design with three replications in each location. The combined analysis of variance for grain yield indicated that the differences among all sources of variation were highly significant (P<0.01). Environment (E), Genotype (G) and G × E interaction effects explained by 25.54%, 17.02% and 48.97% for inbred and 35.26%, 17.03%, 31.23% for hybrid of the total sum of square, respectively. Locations E2 (Chattogram); E3 (Dhaka) for inbred and E2 (Chattogram); E4 (Khulna); E5 (Rajshahi); E7 (Sylhet) for hybrid varieties were found most discriminating and more informative among all. Ideal environment was found in E6 (Rangpur) for inbred and E4 (Khulna) for hybrid varieties. According to GGE mean and stability biplot, the most stable genotypes were G18 (BRRI dhan34); G26 (BRRI dhan52); G28 (BRRI dhan57); G19 (BRRI dhan37); G13 (BR25); G27 (BRRI dhan56); G21 (BRRI dhan39) for inbred and G2 (BADC hybrid dhan-2); G4 (BADC hybrid dhan-6); G5 (Bayer hybrid dhan-4) for hybrid compared to the other genotypes. The ideal genotypes were found G18 (BRRI dhan34) for inbred and G26 (BRRI hybrid dhan6) for hybrid varieties. In summary, we identified stable genotypes adapted across the environments for grain yield. These genotypes can be used as commercial cultivation with sustainable production as well as a parent/pre-breeding material in future rice breeding program.
 Bangladesh Rice J. 24 (1): 59-71, 2020

Assessment of Genetic Variability and Correlation of Yield Components of Elite Rice Genotypes (Oryza sativa L.)

The study was conducted to evaluate the extent of variability among the elite rice (Oryza sativa L.) genotypes for yield and yield components. Sixteen elite rice genotypes were evaluated for yield and yield contributing characters in Bangladesh Rice Research Institute, Regional Station, Satkhira. Highest grain yield (t ha-1) was observed in BR(Bio)8333-BC5-2-16, which was followed by BR16, BRRI dhan28, BRRI dhan58 and BRRI dhan29. BR7671-37-2-2-37-3-P3 had the highest number of grains per panicle with minimum thousand grain weight. Correlation analysis revealed that the number of panicles per plant (0.301), days to 50% flowering (0.606) and grain yield per plant (0.393) had the significantly positive contribution to grain yield. After evaluation of yield components, four genotypes namely BR(Bio)8333-BC5-1-20, BR(Bio)8333-BC5-2-16, BR(Bio)8333- BC5-2-22 and BR(Bio)8333-BC5-3-10 were selected as outstanding genotypes, which can be used as potential breeding materials for variety development or in the crossing program to enrich the rice gene pool in Bangladesh.
 Bangladesh Rice J. 24 (1): 21-29, 2020

Zerovalent Iron Modulates the Influence of Arsenic-Contaminated Soil on Growth, Yield and Grain Quality of Rice

This study aimed to investigate the effects of zerovalent iron (ZVI/Fe0) on growth, yield and grain quality of rice (Oryza sativa L.) cv. BRRI dhan49 in arsenic (As)-contaminated soils. The pot experiment was arranged in a complete randomized design (CRD). The treatments on rice applied were As in soils at As0 (0 mg kg−1), As20 (20 mg kg−1), and As40 (40 mg kg−1) with a combination of ZVI at ZVI0 (0%), ZVI0.5 (0.5%), ZVI1.0 (1.0%), and ZVI1.5 (1.5%) with three replications. Contents of phosphorus (P), potassium (K), manganese (Mn), zinc (Zn), iron (Fe), and As in grains of rice; and Fe and As content in cultivated soils were determined. The application of ZVI had negative or no effect on shoot weight, tiller number, and grain yield. Although application of ZVI had little or no effect on thousand grain weight, P, K, Zn, and Mn of rice grains, Fe content in rice grains was increased by ZVI treatments in a dose-dependent manner. The grain As content was non-significantly reduced by the ZVI application. Soil bacterial population was negatively influenced by the ZVI in a dose-dependent manner which might be linked with As content in the soils. Therefore, a further elaborative study is needed to elucidate the mechanisms of the effects of ZVI and soil As on rice and rhizosphere soil microorganisms.

EFFECT OF TWO STAGE DRYING EMPLOYING FLUIDIZED BED DRYING, TEMPERING FOLLOWED BY FIXED BED DRYING ON HEAD RICE YIELD OF BRRI DHAN28 RICE VARIETY IN BANGLADESH

Drying of high moisture paddy to achieve quality milled rice is an important issue in a paddy producing country like Bangladesh. This study has been conducted to investigate the impact of two stage drying technique namely, fluidized bed drying, tempering and followed by fixed bed drying method on quality of BRRI Dhan28 rice variety in terms of head rice yield (HRY). Moist paddy was dried in fluidized bed dryer (FBD) as first stage drying to reduce moisture from 25-27% to 18-19% using three drying temperatures of 120, 130, and 150°C at three bed thicknesses of 8, 10, and 12 cm. The first stage dried samples were immediately tempered for 30 minutes and dried in second stage drying by fixed bed dryer using 40±10C temperature maintaining bed thickness as 30 cm for the further reduction of moisture content to 13-14% (wb). Sun drying method was followed as complete drying of control sample. Control sample was used to compare the milling quality of rice dried in two stage drying technique. In addition, head rice yield was also compared to existing industrial paddy drying complexes. The results revealed that HRY of rice samples obtained from different drying methods was comparable. All the sets of drying parameters in two stage drying yielded better quality HRY than the control and even existing industrial drying method. The highest HRY (53.43%) of milled rice was obtained in the two-stage drying. On the other hand, the samples dried in the sun drying and industrial drying using Louisiana State University (LSU) dryer yielded 49.77% and 48.25% HRY, respectively. Therefore, the two-stage drying technique can be used for drying of high moisture paddy to obtain quality dried rice.