BRRI Dhan29 Research Articles

Characterization of Multiple Grain Rice (Oryza sativa L.) Biramsundari from Bangladesh

Biramsundari is a rice germplasm from Bangladesh showing one to four grain in a single seed. Comparative study of morphological traits revealed that BS is a taller rice variety compared to modern rice varieties with longer and wider flag leaves, longer panicle length and higher thousand seed weight (TSW) than transplanted aman rice variety BRRI dhan 49. Flower morphological analysis unveil that multiple grains of Biramsundari are originating from multiple number of carpels in each floret. About 40.1% flower contains three carpels. Fluorescent microscopic study also confirms the zygotic origin of multiple grain formation in Biramsundari. Molecular characterisation of Biramsundari was performed by using TeaCpSSR27 and TeaCpSSR28 chloroplast microsatellite markers. The results of this investigation reveal that atpF and rsp14-psaB intergenic spacer regions of Biramsundari have variation compared to sequences of with O. sativa ssp. indica, O. sativa ssp. japonica and O. rufipogon. Plant Tissue Cult. & Biotech. 31(2): 115-122, 2021 (December)

Performance of double grained rice cultivar under different plant spacing

Plant spacing ensures uniform and optimum plant population and facilitates sufficient natural resources for crop growth which, in turns influences the crop yield positively. An investigation was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, during July to December 2017 to study the influence of plant spacing on the yield of double grained rice cultivar. The study comprised five spacing viz. 25 cm × 15 cm, 25 cm × 10 cm, 20 cm × 15 cm, 20 cm × 10 cm and 15 cm × 15 cm and two rice cultivars viz. a double grained rice cultivar and BRRI dhan49 and a double grained rice cultivar. It was laid out in a randomized complete block design with three replications. The double grained rice cultivar produced taller plant (155.65 cm), longer panicle (23.93 cm), higher 1000-grain weight (25.96) and higher straw yield (6.90 t ha-1), though the higher grain yield (3.68 t ha-1) was found in the test cultivar (BRRI dhan49). Planting at 20 cm × 15 cm produced the highest grain yield (3.70 t ha-1) which was at par with 25 cm × 15 cm, 25 cm × 10 cm and 20 cm × 10 cm while planting at 15 cm × 15 cm produced the lowest grain yield (3.13 t ha-1). The interaction of the double grained rice cultivar with all spacing combinations produced taller plants than the spacing combinations with BRRI dhan49. The higher grain yield (3.52 t ha-1) was found in the double grained rice cultivar with 20 cm × 10 cm spacing which was at par with the spacing of 20 cm × 15 cm and 25 cm × 15 cm, respectively; although BRRI dhan49 always produced the higher yield. The lowest grain yield (3.08 t ha-1) was recorded at the double grained rice cultivar with 25 cm × 10 cm spacing, however, the same treatment produced the highest biological yield (11.23 t ha-1) due to the highest straw yield (8.15 t ha-1). Hence, the spacing 20 cm × 15 cm might be recommended for the higher grain yield in the double grained rice cultivar
 Res. Agric., Livest. Fish.8(3): 273-279, December 2021

Effect of variety and nitrogen fertilizer managements on the growth and yield of Transplant aman rice managements

Varietal selection and appropriate placement of nitrogen fertilizer could reduce the magnitude of nitrogen losses to a considerable extent and improve its use efficiency for better grain production. An experiment was carried out during the period from July to December at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh to evaluate the effect of variety and nitrogen fertilizer management on the growth and yield of transplant aman rice. The treatments consisted of three varieties viz. BR11, BRRI dhan49 and Binadhan-7, and five nitrogen fertilizer managements viz. two depth of placement of USG (Urea Super Granule) and three split applications of prilled urea. The experiment was laid out in a randomized complete block design with three replications. The results showed that the effect of variety and nitrogen fertilizer management significantly influenced all the yield contributing characters except weight of 1000- grains, non-effective tillers hill-1 and panicle length. The highest grain yield (3.69 t ha-1) was obtained from Binadhan-7. In the case of nitrogen fertilizer management, the highest grain yield (4.32 t ha-1) was found from the 6 cm depth placement of USG. The highest grain yield (4.82 t ha- 1) was observed from the interaction of Binadhan-7 with the 6 cm depth of placement of USG. It may be concluded that Binadhan-7 with 6 cm depth of placement of USG appeared as the promising practice to maximize the yield of transplant aman rice.
 Res. Agric., Livest. Fish.8(3): 281-289, December 2021

Growth and yield response of drought tolerant transplant aman rice cultivars to nitrogen fertilization

An experiment was conducted at the Agronomy Field Laboratory of Bangladesh Agricultural University, Mymensingh during the period from July to December 2018 to evaluate the effect of different levels of nitrogen on growth and yield of drought tolerant transplant aman rice cultivars. The ex- periment was consisted of one check variety BRRI dhan49 and three drought tolerant rice varieties BRRI dhan56, BRRI dhan66 and BRRI dhan71 along with five nitrogen levels such as no nitrogen (control treatment), 50%, 100%, 125% and 150% of recommended dose (RD) where the recommended dose was 150 kg N ha−1. Nitrogen was applied in the form of urea (46.66% N) as top dressing in three equal splits at 15 days after transplanting, 30 DAT and 45 DAT. The experiment was laid out in a randomized complete block design with three replications. The result of the study reveals that BRRI dhan66 produced the highest number of total tillers hill−1, effective tillers hill−1 and grains panicle−1. The highest 1000-grain weight and grain yield was recorded in BRRI dhan71 which was statistically identical to BRRI dhan66. In case of level of nitrogen, the highest number of total tillers hill−1 was observed in 125% RD of N. The highest number of effective tillers hill−1 was found in 100% of RD of N and the maximum number of grains panicle−1 was observed in 150% of RD of N. The highest grain yield was obtained from 125% RD of N which was statistically identical to 100% and 150% of RD of N. In case of interaction the highest number of total tillers hill−1 was recorded in BRRI dhan56 with 125% RD of N which was statistically identical to BRRI dhan66 with 100% RD of N. The highest number of grains panicle−1 was observed in BRRI dhan66 with 150% of RD of N. BRRI dhan56 with 150% RD of N produced the highest 1000-grain weight. The highest number of effective tillers hill−1, grain yield and straw yield were recorded in BRRI dhan66 with 100% RD of N. In conclusion, the result of the study revealed that application of 100% recommended dose of N (150 kg ha−1) is suggested as the best nitrogen management approach for the drought tolerant rice cultivar BRRI dhan66 for its better performance.

Comparative Performance and Economics of Different Zinc Application Approaches in Boro Rice

Zinc deficiency is now very common in Bangladesh causing significant yield losses of different crops including rice. Due to zinc and other micronutrient deficiencies the high yielding rice varieties fail to produce their potential yield even under good management practices. Although many farmers have started applying zinc fertilizer they are not aware of proper dose and application method. Therefore, in many cases farmers are applying zinc fertilizers indiscriminately without considering the efficacy and economic output. Keeping those in mind the proposed study bears huge importance to elucidate and enrich the present state of knowledge on zinc fertilization in rice for ensuring food and nutritional security of Bangladesh in a sustainable way. An experiment was therefore conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh during the period from December 2020 to May 2021 to investigate into the effects of different doses of Zn applied through soil, root soaking and foliar on rice growth and yield and their economics in Boro seasons following a randomized complete block design with three replications. Two Boro rice varieties (BRRI dhan58 and Hira Dhan-1) and seven different zinc application approaches (including soil application, root dipping and foliar spray of zinc with different dose/concentration). Hybrid variety Hira Dhan-1 performed better than BRRI dhan58. Application of zinc resulted in better crop growth and higher yield. Soil application appeared as the most efficient approach. Grain yield increased over control due to zinc application raged from 5.1 to 14.7%. Present study confirms the necessity of zinc fertilizer application for increasing Boro rice yield. Among the different application approaches, soil application was found most effective and foliar spray was least effective. Although soil application of ZnSO4 @ 10 kg ha-1 produced the highest yield, application of ZnSO4 @ 5 kg ha-1 was the most economic one. Hybrid rice Hira Dhan-1 out yielded high yielding inbred variety BRRI dhan58. Therefore, it is recommended to cultivate hybrid rice in Boro season with soil application of ZnSO4 @ 5 kg ha-1 for higher yield and better economic return.

Seed Priming Influence on High Temperature Tolerance and Weed Suppressive Ability of Late Sown Dry Direct Seeded Winter Rice

Seed priming is a pre-sowing hydration technique which leads to a physiological condition triggering germination and enhancing uniform seedling emergence. It is a promising tool for enhancing drought tolerance in plants which is essential for promoting economic development by coping up with the adverse effects of climate change on crop productivity. So, a better understanding of seed priming efficacy is required. Therefore an experiment was conducted with a view to investigating the effect of seed priming agent on the weed growth and yield performance of high yielding rice variety BRRI dhan29 sown on different dates following dry direct seeded condition in boro season. Two sowing dates viz., 20th January (early or optimum sowing as control) and 20th February (late sowing as high temperature stress during reproductive stage) and seed priming agents included NaCl (20000 and 30000 ppm), KCl (20000 and 30000 ppm), CaCl2 (20000 and 30000 ppm), CuSO4 (50 and 75 ppm), ZnSO4 (10000 and 15000 ppm), Na2MoO4 (2 and 3 ppm) and PEG (100 and 150 ppm) were used. Plant height and tillers of BRRI dhan29 were significantly enhanced when seeds were sown early (20th January) and due to seed priming at early stage and at harvest. Among the yield parameters grains panicle-1, grain yield, and straw yield were produced more by early sowing (20th January). Grains panicle-1, 1000-grain weight, and grain yield were positively influenced due to seed priming. Considering the growth and yield parameters and yield of rice, early sowing and seed priming with KCl or CaCl2 were found as the best. Seed priming produced no significant effect on the weed growth. There was no significant effect of interaction between sowing date and priming agent on crop characters and yield parameters. Therefore, seed priming with 20000 ppm KCl or 20000 ppm CaCl2 and early sowing is recommended for increasing the yield of dry direct seeded boro rice (BRRI dhan29). If somehow early sowing is not possible, seed priming with 20000 ppm KCl or 20000 ppm CaCl2 is highly recommended or mitigating temperature stress during reproductive stage and enhancing yield of BRRI dhan29 under dry direct seeded, late sowncondition.

INCREASING CROPPING INTENSITY AND PRODUCTIVITY THROUGH FOUR CROPS BASED CROPPING PATTERN IN DINAJPUR REGION OF BANGLADESH

A four crops-based trial was conducted for the two consecutive years at MLT site Raniganj, Sadar, Dinajpur and Kashiatola, Ghoraghat, Dinajpur during 2015-16 and 2016-17 to develop a sustainable and economically profitable cropping pattern Potato-Boro-T. Aus-T. Aman against the farmers existing pattern Fallow-Boro-Fallow-T.Aman. The experiment was carried out in RCB design with six dispersed replications. Suitable and short duration high yield potential varieties of different crops Potato ((BARI Alu-7), Boro (BRRRI dhan28) T.Aus (BRRI dhan48) and T.Aman (BRRI dhan62) were selected for the experiment. Grain yield of rice and potato tuber yield was satisfactory. Inclusion of two crops (Potato and T. Aus rice) in the existing pattern attributed to the higher system productivity. The improved alternate cropping pattern produced the higher gross return and gross margin compared to the farmers existing pattern. The marginal benefit cost ratio (MBCR) over the existing pattern was 2.01 at Ghoraghat and 1.85 at Raniganj which indicated the superiority of the alternate pattern over the farmer’s practice. Potato based cropping pattern could be most suitable and profitable pattern in these areas. From the two years observations in both the locations, four crops pattern could be recommended for higher system productivity and economic benefit along with for more employment opportunity.

Growth-stage-sensitivity of four HYV rice cultivars to irrigation water salinity

Application of fresh water at the salinity-sensitive growth stage(s) and saline water of tolerable salinity level at the less sensitive stage(s) may be an effective irrigation technique for rice (Oryza sativa L.) cultivation in fresh water-scarce salt-affected areas. However, implementation of this technique requires adequate prior information on the sensitivity of growth stages of the rice cultivars to salinity of irrigation water. The objective of this study was therefore to identify the sensitivity of growth stages of Binadhan-8, Binadhan-10, BRRI dhan28 and BRRI dhan47 to salt stress by irrigating the crops with fresh water (control), and saline water of 6, 9 and 12 dS m1 at establishment, tillering, panicle formation, flowering, maturity and all growth stages of the crops. The experiment was laid out in a split-split pot arrangement following a completely randomized design (CRD) with three replications. The establishment and flowering stages of the rice cultivars were found to be the most sensitive to salt stress. Therefore, irrigation at these growth stages with fresh water and at the other growth stages with saline water would be an appropriate strategy for cultivation of the tested rice cultivars in fresh water-scarce saline areas like the coastal saline region of Bangladesh.

Efficacy and Economics of Different Weed Control Practices in boro Rice under High Ganges River Floodplain of Bangladesh

Weed management practices are crucial for controlling weeds as they reduce yield, increase the production cost as well as deteriorate the grain quality. So, an experiment was conducted at Monirampur, Jashore, Bangladesh during July 2020 to June 2021 to find out the appropriate weed management practices in boro rice. BRRI dhan29 was selected as planting material to see the effect of seven different weed management practices such as no weeding, pre-emergence, post-emergence, pre-emergence followed by (fb) hand weeding (HW) at 40 DAT, post-emergence fb HW at 40 DAT, pre-emergence fb post-emergence and two HW at 20 and 40 DAT following single factor randomized complete block design (RCBD) with three replications. The study revealed that Poaceae and Cyperaceae contributed more weeds among 15 different families. Monochoria vaginalis, Fimbristylis miliacea, Echinochloa crus-galli, Cyperus rotundus and Alternanthera sessilis were more abundant among 34 weed species. The highest weed density (98.22 m−2 ) and dry weight (51.36 g m−2 ) were found in no weeding condition but that of the lowest value (weed density: 9.93 m−2 and dry weight: 3.59 g m−2 ) was observed in pre-emergence fb one HW at 40 DAT. The highest grain yield (6.52 t ha-1 ), net income (91571 Tk ha-1 ) and B:C ratio (1.9) were recorded in pre-emergence fb HW at 40 DAT followed by pre-emergence fb post-emergence treatment. The lowest value of grain yield (3.29 t ha-1 ), net income (12290 TK ha-1 ) and B:C ratio (1.14) were found in no weeding treatment. As per results, it can be concluded that pre-emergence fb HW at 40 DAT has been revealed as the best weed management practice for BRRI dhan29.

MUTAGENESIS FOR THE DEVELOPMENT OF SUBMERGENCE TOLERANCE RICE GENOTYPES in Indica BY GAMMA IRRADIATION-INDUCED MUTATION USING 60CO SOURCE ISOTOPE WITH MARKER ASSAY

The high selection pressure applied to rice breeding since it was domesticated thousands of years ago has initiated a narrowing its genetic variability. Obtaining new rice varieties therefore becomes a major challenge for breeders and the development of techniques to increase genetic variability has attracted the attention of various research groups. Understanding mutations and their application has paved the way for the interpretation of immersion tolerant rice. Creating variability through mutations has therefore become the most important tool for rice improvement. Gamma-rays were able to create genetic variables for abiotic stress tolerance, such as submergence tolerance as well as plant height, number of tillers, shoot and root weight, total biomass, and panicle length. Among the three parents of BRRI dhan52, Guti swarna and Mamun swarna, the highest average yield plant-1 (46.56 g) was produced by Mamun swarna (cont.) and the lowest (18.16 g) by BRRI dhan52. On the other hand, the group of all mutants, Mamun swarna-250 (M3) was more productive (39.30 g) and the maturation was 142.66 days from Guti swarna-300 (M3) (20.20 g) and maturity duration was 151.66 days. The first three principal components studied, including the Eigen value, explained 80.4% of the total variation in 11 rice genotypes for 9 quantitative traits. The gene diversity value of allele across 11 genotypes was 0.469. The value of polymorphism information content (PIC) was 0.359 (SC34 / RM23679) and the allele frequency (%) was 62. However, this assessment may be effective in developing reliable mutants for significant submergence stresses in rice.

Effect of Soil Application of Zinc on Growth, Yield and Zinc Concentration in Rice Varieties

Zinc (Zn) deficiency is widespread nutrient disorder in lowland rice growing areas in Asia, especially in Bangladesh. Intensive cropping with modern varieties causes depletion of inherent nutrient reserves in soils. The application of Zn fertilizers results in higher crop productivity and increases Zn concentration in crops. A field experiment was conducted to evaluate the effect of Zn application on growth, yield, and grain-Zn concentration in eight varieties of rice. The experiment was laid out in a split plot design with a distribution of Zn rates (0 kg ha-1 and 3 kg ha-1 from ZnO) to the main plots and rice varieties (BRRI dhan49, BRRI dhan52, BRRI dhan56, BRRI dhan57, Kalizira, Biroin, Gainja and Khirshapath) to the sub-plots. Zinc application improved effective tillers hill-1, grains panicle-1 and 1000-grain weight which impacted the grain yield of rice. Among the eight rice varieties, a significant increase of grain yield was recorded in BRRI dhan49, BRRI dhan52, BRRI dhan56 and BRRI dhan57 due to application of Zn. Zinc concentration of grain significantly increased in all rice varieties except Biroin. The highest grain-Zn concentration (19.1 mg kg-1) was noted in BRRI dhan57 with 3 kg ha-1 Zn and the lowest value (11.3 mg kg-1) was observed in BRRI dhan52 without Zn application. The highest percent increase of grain Zn concentration over control was obtained in high yielding rice variety BRRI dhan49 and the lowest Zn concentration was found in local rice variety Biroin.

Adoption and adaptability of modern Aman rice cultivars in Faridpur region - Bangladesh

Rice is not just a staple food; but it is at the center of culture, politics, and economy of Bangladesh. The determinants affecting the adoption of modern rice cultivars and their adaptability in the Aman season (June to November) at the Faridpur region in Bangladesh were discussed. A total of 500 farmers from five different districts such as, Faridpur, Madaripur, Shariatpur, Rajbari, and Gopalganj through multistage sampling technique participated in the survey. Before the survey, 15 farmers were selected for the cultivation of eight modern T. Aman rice cultivars in their fields during three consecutive years 2018 to 2020 in the mentioned five districts of Bangladesh. A structured questionnaire was used to identify the determinants associated with the adoption of modern rice cultivars by replacing the popular old ones. Results revealed that beyond preferences, some other determinants (age, education, risk aversion, land size, yield, and perception of modern rice cultivars and their seed availability) directed the decision to adopt or not. Considering the average grain yield of the tested rice cultivars, the genotypes BRRI dhan72 (G-6) and BRRI dhan87 (G-8) were the high yielding cultivars for the above five districts. Despite having a comparatively low yield, the cultivars BRRI dhan71 (G-4) and BRRI dhan49 (G-3) were more stable compared to other cultivars in the Faridpur region of Bangladesh.

Profitability Analysis of a Four Crop Based Cropping Pattern in Bogura Region of Bangladesh

Farmers in the Bogura region benefit significantly from the systematic use of crop rotation. The experiment was performed at the Shibganj, Bogura, in 2015-16 and 2016-17 to create a potato-Boro-radish-T. Aman rice crop sequence that would compete with the potato-Boro-T. Aman rice crop sequence. Primary objectives of the experiment were to determine the cost of producing enhanced Potato-Boro-Radish-T. Aman rice and compare it to current potato-boro-t. aman rice. There were two patterns: Current Cropping Pattern Potato (BARI Alu-8)-Boro (BRRI dhan 28)-T. Aman (BRRI dhan-49) and Alternative Cropping Pattern Potato (BARI Alu-25)-Boro (BRRI dhan 28) -Radish (Rocky)-T. Aman (BRRI dhan-57). The research revealed that an alternative cropping pattern required average crop duration of 315 days to complete one cycle in a year, implying that a four multiple cropping sequence was economically viable to replace the current cropping pattern. In terms of mean REY, the total grain/tuber yield was 42.80 t/ha/year, which was 66% greater than the current pattern (25.76 t/ha/year). The overall production efficiency (185.14 kg/ha/day), usage of land (86.16%), and engagement in the population (660 man-days/ha/year) of the alternative cropping pattern were 45, 7, and 41% higher, respectively, than the current cropping pattern. Alternative cropping patterns had the gross benefit of 274911 Tk./ha/year, indicating that they were sparingly sustainable. The alternative crop sequence also improved crop strength, growers' real understanding, technique, profits, and engagement. Furthermore, by trying to incorporate T. aman straw into soil with an alternative cropping pattern, it promotes soil health. As a result, farmers in Bangladesh's Bogura region may employ a different planting pattern on their variable land in order to boost production and profitability while also creating jobs.

Impacts of different nitrogen forms and doses on agronomic performance of BRRI dhan29

Nitrogen (N) is one of the most important nutrients for rice cultivation and probably the hardest to maintain in soil. This experiment was conducted to investigate the impacts of different N forms and doses as urea on BRRI dhan29 during boro season in Meherpur district, Bangladesh. The two most abundant forms of urea namely granular urea (GU) and urea super granule (USG) were selected with five doses (0, 100, 150, 200, and 250 kg ha-1) for each form. The treatments were replicated thrice in Randomized Complete Block Design (RCBD). GU was broadcasted and USG was applied using deep placement method. Other fertilizers viz. triple super phosphate, muriate of potash, gypsum, and zinc sulfate were applied at 100, 70, 60, and 5 kg ha-1, respectively. Agronomic parameters were measured by randomly selecting five hills from each plot. Application of N through USG significantly improved almost all agronomic characteristics such as plant height, total and effective tiller hill-1, panicle length, total and filled grains panicle-1, straw and biological yields, grain yield, and harvest index. BRRI dhan29 produced the highest grain and straw yields with the highest dose of USG application (250 kg ha-1). The 1000-seed weight was not significantly affected by N doses or by forms that might be due to its genetically controlled trait and environmental influence during the grain filling stage. Deep placement of USG ensured adequate N supply for a longer period that resulted in enhancement of growth and yield components of BRRI dhan29.

Yield and Yield Components of Boro Rice as Influence by Nitrogen Application Methods and Weed Management

Two consecutive field experiments were conducted at the Suapur Union of Dhamrai Upazila, Dhaka, is located at 23088´N latitude and 90014´E longitude and AEZ-12, Bangladesh. The purpose of the experiment was to study the combine effect of nitrogen application methods and weed management for maximizing yield and yield components of boro rice (cv.BRRI dhan29).The experiment consisted of four nitrogen management methods and four weed managements. The experiment comprised two factors; Factor A: Nitrogen management (4 levels), N0: No urea (control), N1: Urea super granules-USG (77 kg N ha-1), N2: Prilled urea at recommended dose (150 kg N ha-1) and N3: ½ of the recommended dose (75 kg N ha-1); Factor B: Weed management (4 levels), W0: No weeding (control), W1: Two hand weeding (20 and 40 DAT), W2: Pre emergence herbicide (Butachor) and W3: Post emergence herbicide (Prityloclor). The experiment was laid out in a randomized complete block design with three replications. Data on different yield components and yield of BRRI dhan29 were recorded. Statistically significant variation was observed for their combined effect. The highest grain yield (6.80 t ha-1) was obtained from the interaction between urea super granules-USG (77 kg N ha-1) and pre emergence herbicide (Butachor), whereas whereas the lowest (3.85 t ha-1) from the interaction between no urea (control) and no weeding (control). From the results of the study it can be concluded that the application of urea super granules-USG (77 kg N ha-1) and pre emergence herbicide (Butachor) condition might be used for obtaining the best performance of BRRI dhan29.

Characterization of transcription factor MYB59 and expression profiling in response to low K+ and NO3− in indica rice (Oryza sativa L.)

BackgroundNitrogen and potassium are crucial supplements for plant development and growth. Plants can detect potassium and nitrate ions in soils and in like way, they modify root-to-shoot transport of these ions to adjust the conveyance among roots and shoots. Transcription factor MYB59 plays essential roles in numerous physiological processes inclusive of hormone response, abiotic stress tolerance, plant development, and metabolic regulation. In this study, we retrieved 56 MYB59 proteins from different plant species. Multiple sequence alignment, phylogenetic tree, conserved motif, chromosomal localization, and cis-regulatory elements of the retrieved sequences were analyzed. Gene structure, protein 3D structure, and DNA binding of OsMYB59 indica were also predicted. Finally, we characterized OsMYB59 and its function under low K+/NO3− conditions in Oryza sativa subsp. indica. ResultsData analysis showed that MYB59s from various groups separated in terms of conserved functional domains and gene structure, where members of genus Oryza clustered together. Plants showed reduced height and yellowish appearance when grown on K+ and NO3− deficient medium. Quantitative real-time PCR uncovered that the OsMYB59 reacted to abiotic stresses where its expression was increased in BRRI dhan56 but decreased in other varieties on K+ deficient medium. In addition, OsMYB59 transcript level increased on NO3− deficient medium. ConclusionsOur results can help to explain the biological functions of indica rice MYB59 protein and gave a theoretical premise to additionally describe its biological roles in response to abiotic stresses particularly drought.

Effect of long-term nutrient management practices on soil health and paddy yield of rice-rice-fallow cropping system in tropic humid climate

Long-term repeated nutrient management practices may have impact on soil health and sustainable paddy (Oryza sativa) production. Therefore, a long-term (33 years) field experiment was conducted at Bangladesh Rice Research Institute in Gazipur with the objective of finding the impact of repeated inorganic and integrated nutrient management (INM) practices on soil biochemical properties, soil quality and its cumulative effect on paddy yield. Experiment was permanently laid out in a replicated complete block design with three replications and modern paddy varieties, BRRI dhan49 and BRRI dhan29, were grown in wet and dry seasons respectively. Treatments imposed were; balanced chemical fertilizer (BCF), K minus from BCF, P minus from BCF, N minus from BCF, Chemical fertilizer with 3 t ha−1 decomposed cowdung (CD), Chemical fertilizer with 2 t ha−1 decomposed poultry litter (PL) and Fertilizer control. The SOC decreased 8% due to 33 years BCF compared to initial soil and increased 18% in INM compared to BCF practice during last 10 years. Long term BCF practices did not bring significant changes in soil pH, however 0.09 units increased and 1.45% bulk density decreased in PL-INM practice. Urease and phosphatase activities, total bacteria, phosphate solubilizing bacteria, free-living N2 fixing bacteria, water stable aggregates, NH4+-N, available P, exchangeable K were increased in INM practices and between two INM treatments, PL was superior over CD. The highest SQI (0.93) and 10 years’ average paddy yield per season (4.99 t ha−1) was obtained in PL-INM followed by CD-INM (SQI, 0.80 and grain yield 4.12 t ha−1) and the lowest in the N minus from BCF practice (SQI, 0.16 and paddy yield 3.2 t ha−1) and control (SQI, 0.33 and paddy yield 2.9 t ha−1) treatment. SQI due BCF practice was 0.68 and average paddy yield was 4.36 t ha−1. The results of AreaSQI revealed that NH4–N, available P and enzyme activities are the most sensitive soil parameters that degraded due to different nutrient management practices. The study also proved that imbalance fertilizer application, especially removal of N nutrition, was the most detrimental for paddy soil quality and PL-INM treatment is the best nutrient management practice for maintenance of soil health in the hyperthermic vertic endoaquepts and tropical humid climate.

Translocation of Soil Arsenic towards Accumulation in Rice: Magnitude of Water Management to Minimize Health Risk

Globally, the risk of arsenic (As) contamination in soil and rice is well documented across the globe. In Bangladesh, drinking water and rice are two major exposure pathways of As to humans. Therefore, the efficiency of recent technologies to reduce rice As and associated human health risks still need to be deeply investigated. In this direction, a pot experiment was performed to investigate the impact of soil As and agronomic irrigation management on rice (cv. BRRI dhan28) growth, yield, As accumulation, and finally, health risks to humans from consuming rice. Treatment combinations were made with three levels of As (0, 20, and 40 mg kg−1) having two irrigation procedures, including alternate wetting and drying (AWD) and traditional continuous flooding (CF). According to the findings, As pollution in the soil lowered the yield contributing features and rice yield, including panicle length, filled grains per panicle, sterile grains per panicle, 1000-grain weight, grain yield, and straw yield. AWD water management significantly improved the growth performance and productivity of rice. Grain yield was increased by 13% in AWD compared to CF. Rice grain and straw As concentrations were increased to 0.56 mg kg−1 and 15.10 mg kg−1, respectively, in soil with 40 mg kg−1 As and CF water management. AWD treatment significantly reduced grain and straw As contents by 16% and 28%, respectively. Increased grain, straw, and total As uptake was noticed with higher soil As concentrations. The study also found that rising soil As raised non-carcinogenic risks (HQ > 1) and carcinogenic risks (CR > 1.010–4) while AWD lowered health risks compared to CF. Thus, rice farming using AWD irrigation could be a viable and long-term solution for reducing As contamination in rice and associated human health hazards.

Alleviation of arsenic accumulation in rice by applying silicon-rich rice husk residues in Bangladesh soil

While the accumulation of arsenic in rice (Oryza sativa L.) has been highlighted as a major concern in Bangladesh, sustainable measures are critically needed to reduce the uptake of arsenic by rice plants. In the present study, a pot-experiment was conducted using a Boro rice variety (BRRI dhan-29) in two geomorphologically different soils from Holocene floodplains and Pleistocene terraces, in which silicon-rich fresh rice husk (FRH) and rice husk ash (RHA) were applied, as silicon fertilisers, in the soils at the rate of 1% (w/w) of rice residue:soil.In the Holocene floodplain soils, the application of FRH was found to decrease arsenic in grain, husk and straw by 42, 56 and 51%, respectively, whereas the soil incorporation of RHA decreased arsenic in grain, husk and straw by 26, 37.5 and 36%, respectively. In the Pleistocene terrace soils, the application of FRH reduced the grain, husk and straw arsenic by 38, 38 and 44%, respectively, whereas the RHA decreased the grain, husk and straw arsenic by 26, 30 and 29%, respectively. Fresh rice husk was found to be more effective in alleviating arsenic accumulation in rice than RHA. In both the Holocene floodplain and Pleistocene terrace soils, the grain concentrations of calcium, phosphorus, silicon, and zinc were found to be increased with the decrease of arsenic in the grain due to the use of FRH and RHA. The present study suggests that silicon-rich rice husk residue scan be used as silicon fertilisers to reduce arsenic accumulation in rice in Bangladesh. Bangladesh J. Sci. Ind. Res.56(3), 195-206, 2021

RESPONSE OF RICE VARIETIES GROWN ON CALCAREOUS AND ACID MIXED SOILS AMENDED BY VERMICOMPOST UNDER VARIABLE CLIMATES

A field experiment was conducted to explore how rice (BINA Dhan 11 and BRRI Dhan 34) responds in modified soil and climatic conditions. They were planted on artificially prepared soil beds by mixing calcareous and acid soils in 1:1 and 1:3 ratios. Soil temperature (St) was elevated up to 20C over the diurnal ones. Moisture (M) was maintained at 50%, 70%, and saturated (100%) soil conditions. Vermicompost (V) was applied at the rates of 0, 10, and 15 tha-1. The number of tillers and plant height were recorded at 25 days intervals. The maximum number of 26 and 27 tillers for BINA Dhan 11 and BRRI Dhan 34 were recorded. The longest plant height was observed with the T10 (V15M100) treatment. The treatment T3 (V15M100) resulted in maximum fresh weight of shoot and shoot dry matter production for both rice varieties in 1:3 mixed soil. Both varieties performed well in 1:3 mixed soils and elevated temperature conditions, as observed for normal soils. This evidence concluded that the improvement of calcareous and acid soils through their mixing is a successful approach and confirmed by the treatments' usual responses on different rice growth parameters under these mixed soils.