BRRI Dhan29 Research Articles

Yield Performance of Two Drought Tolerant Rice Mutants in Boro Season at Two Semi Drought Prone Areas of Bangladesh

Climate change is the biggest challenge for sustainable crop production all over the world, where drought is one of the outrageous factors. Two experiments were conducted to examine the suitability and productivity of drought tolerant two rice mutants cultivating in Boro season. The experiments were consisted of two mutants, derived from NERICA rice variety namely, RM-16(N)-8-1, RM-16(N)-10-1 and one Boro variety BRRI dhan58 and they were conducted at the farmer’s field of two semi drought prone areas as Mymensingh and Jamalpur districts of Bangladesh from December, 2021 to May, 2022. The experiments were laid out in Randomized Complete Block Design (RCBD) with three replications. Higher yield (7.01 tha-1) was recorded in the mutant RM-16(N)-10-1 compared to the variety BRRI dhan58 (6.46 tha-1). Higher days to maturity was found in BRRI dhan58 (151.50 days) compared to the mutants RM-16(N)-10-1 (150.50 days) and RM-16(N)-8-1 (148 days). The highest effective tiller hill-1 (25.10) and number of filled grain panicle-1 (142.50) were recorded in the mutant RM-16(N)-10-1 where in RM-16(N)-8-1, effective tiller hill-1 and number of filled grain panicle-1 were 22.88 and 138.92 respectively, and in BRRI dhan58 effective tiller hill-1 was 21.56 and number of filled grain panicle-1 was 142.46. Higher 1000 seed wt. (23.53 g) was found for RM-16(N)-10-1 compared to other two genotypes. And the maximum yield potential (7.01 tha-1) was recorded in the mutant RM-16(N)-10-1. Furthermore, it will be useful for Bangladesh to choose drought tolerant genotypes with high yield potential and future breeding stock.

Paired growth of cultivated and halophytic wild rice under salt stress induces bacterial endophytes and gene expression responses.

Utilizing salt-affected marginal lands in coastal regions can help meet the growing demand for rice. We explored a nature-based solution involving wild halophytic rice (O. coarctata, Oc) and commercial rice BRRI Dhan 67 (O. sativa, Os) grown in close proximity to each other under salt stress. This was to investigate whether a paired planting strategy could help complement rice growth and yield under stress. We also investigated the gene expression and endophytic bacterial profiles of both Os and Oc in unpaired and paired conditions without and with salt. Paired plants exhibited lower salt damage indicators such as smaller reduction in plant height, electrolyte leakage and chlorophyll loss, as well as higher K+/Na+ ratio under saline stress. Some of the 39 endophytic bacteria in the mutualism experiment were unique to Oc and transferred to Os when paired. Differentially expressed genes in leaves of paired Os versus unpaired Os were 1097 (994 up-regulated, 101 down-regulated) without salt and 893 (763 up-regulated, 130 down-regulated) under salt stress. The presence of Oc plants under salt stress influenced major biological processes in Os, including oxidative stress; chitinase activity; phenylalanine catabolic process and response to ABA. Protein binding and serine/threonine kinase activity were primarily affected in molecular function. The downregulated WRKY transcription factor 22 in paired conditions under salt stress played a role in the MAPK signaling pathway, reducing respiratory cell death. The upregulated auxin-responsive protein IAA18 gene, involved in hormone signaling and cell enlargement, was present only in paired plants. Our findings therefore, offer insights into developing more effective cultivation strategies for sustainable rice production.

Survival, Growth and Yield of Aman Rice Under Varied Duration of Submergence

Sixteen aman rice varieties were screened against two and three weeks of submergence based on their survival, growth and yield performance following split-plot design with three replications. Rice varieties AZ7006, BRRI dhan49, BRRI dhan52 and BRRI dhan57 exhibited the highest survival rate and minimum lodging that were associated with greater dry matter production under two weeks of submergence. Submergence affected the production of tillers, panicle and spikelets resulting lower grain yield than control. All the rice varieties except AZ7006 and BRRI dhan52 died under three weeks of submergence, where a small shoot of these varieties lived. These two varieties took longer time for producing shoot dry matter, tiller, panicle and maturity. Though they produced spikelets, but these were sterile due to low air temperature at flowering stage. Moreover, rice varieties BRRI dhan52, BRRI dhan57, BRRI dhan90 and AZ7006 under two weeks; and BRRI dhan52 and AZ7006 under three weeks of submergence acquired a combination of morphological and yield contributing response that ultimately induced a higher level of submergence tolerance. As the study revealed that BRRI dhan52 and AZ7006 were submergence tolerant, they could be incorporated in breeding program to develop rice variety for submergence tolerant up to three weeks. Ann. Bangladesh Agric. (2022) 26 (2) : 51-70

Improving grain yield and quality by enhancing accumulation of zinc in rice under subtropical condition

One of the primary abiotic factors limiting rice production is zinc (Zn) deficiency. Effective management of Zn in rice soils is crucial, as rice is a staple crop for many nations. To address this issue, a pot trial was conducted at the net house of the Department of Agronomy, Bangladesh Agricultural University, Mymensingh,from December 2019 to May 2020. The trail aimed to assess the impact of zinc on yield performance and grain zinc content of rice. The experiment employed a completely randomized design (CRD) with three replications, involving the applications of six different rates of Zn to three distinct varieties of boro rice. The result revealed that BRRI dhan28 exhibited superior yield and yield-related traits when treated with 12 kg Zn ha-1. Meanwhile, the application of 10 kg Zn ha-1 resulted in the highest Zn content in the grain of BRRI dhan74, considering the quantity of Zn accumulated by the grain. Based on the findings of the study, it can be concluded that applying 12 kg of Zn ha-1 is likely the optimal Zn management strategy to achieve outstanding performance in the rice cultivar BRRI dhan28. Furthermore, applying 10 kg of Zn ha-1 may enhance the Zn content of the grain in BRRI dhan74.

Effects of Root Growth of Deep and Shallow Rooting Rice Cultivars in Compacted Paddy Soils on Subsequent Rice Growth

Rice is often grown as multiple seasons in one year, alternating between flooded and upland systems. A major constraint, introduced from the flooded system, is a plough pan that may decrease rooting depth and productivity of follow-on upland rice. Roots penetrating the plough pan under flooded rice system can leave a legacy of weaker root growth pathways. Deeper rooting rice cultivars could have a bigger impact, but no direct evidence is available. To explore whether a deep rather than a shallow rooting rice cultivar grown in a flooded cropping cycle benefited deeper root growth of follow-on rice in an upland, reduced tillage cropping cycle, a simulated flooded paddy in greenhouse was planted with deep (Black Gora) and shallow (IR64) rooting cultivars and a plant-free control. Artificial plough pans were made in between the topsoil and subsoil to form different treatments with no plough pan (0.35 MPa), soft plough pan (1.03 MPa) and hard plough pan (1.70 MPa). After harvest of this ‘first season’ rice, the soil was drained and undisturbed to simulate zero-tillage upland and planted rice cultivar BRRI Dhan 28. The overall root length density (RLD), root surface area, the numbers of root tips and branching of BRRI Dhan 28 did not vary between plough pan and no plough pan treatments. Compared with the shallow rooting rice genotype, the deep rooting rice genotype as ‘first season’ crop produced 19% greater RLD, 34% greater surface area and 29% more branching of BRRI Dhan 28 in the subsoil. In the topsoil, however, BRRI Dhan 28 had 28% greater RLD, 35% greater surface area and 43% more branching for the shallow rather than deep rooting genotype planted in the ‘first season’. The results suggested that rice cultivar selection for a paddy cycle affects root growth of a follow-on rice crop grown under no-till, with benefits to subsoil access from deep rooting cultivars and topsoil proliferation for shallow rooting cultivars.

Assessment of Genetic Variability for Yield and Yield Contributing Characters in Rice (Oryza sativa L.)

The study was conducted at the department of Genetics and Plant Breeding, Patuakhali Science and Technology University, Bangladesh during the period from April 2018 to August 2018 to study variability, heritability, genetic advance, interrelationship among 14 important characters among the 15 popular rice genotypes of Bangladesh. Significant variation in plant height of BRRI dhan43, in 50% flowering BRRI dhan42 and BRRI dhan43, for days to maturity BRRI dhan42 and BRRI dhan43, for number of unfilled grain per panicle BRRI dhan48, for flag leaf length Lakhi Lata, for flag leaf width Lohar Gura, for panicle plant-1 BRRI dhan27, for number of filled grain per panicle Kalo Jamvi, number of filled grain per panicle Lakhi Lata, for 100-grain weight BRRI dhan48, for yield plant-1 BRRI dhan48 were found. Besides, yield per plant and 100-grain weight showed high genotypic and phenotypic co-efficient of variation while other characters showed moderate genotypic and phenotypic co-efficient of variation, except days to 50% flowering, days to maturity, panicle length, flag leaf length, flag leaf width, dry matter, and harvest index. All but, plant height and spikelet per panicle, all other characters studied in this experiment showed high heritability and high genetic advance in percent of mean. Panicle per plant, no. of filled grain, 100-seed wt., and harvest index are positively correlated. Yield per plant is also significantly and positively correlated with flag leaf length at the genotypic level but non-significant at phenotypic level. Grain yield showed non-significant positive association with flag leaf width and panicle length. Above information suggests that yield per plant would increase with increase of these characters. Path co-efficient analysis suggested that flag leaf length, panicle per plant, and flag leaf width showed moderate to low direct effect, but 100-seed weight showed highest positive direct effect toward yield per plant. Plant height showed a low negative direct effect on grain yield per plant while days to maturity, panicle length, no. of filled grain, no. of unfilled grain per panicle and dry matter had considerable negative direct effect on grain yield per plant and showed a negligible indirect effect. Thus, selection based on maturity period, number of panicles per plant, panicle length and higher number of filled grains per panicle might be effective for improving yield of rice.

BRRI dhan104: BRRI’s Basmati Type Aromatic Rice Variety for Irrigated Ecosystem in Bangladesh

An enhancement over already available premium quality enriched aromatic rice varieties for Bangladesh is the recently announced BRRI dhan104 type of rice, which has long slender grain and is high yielding and ideal for Bangladesh's irrigated ecology. The variety has satisfactorily passed the Proposed Variety Trial (PVT) conducted in the farmers’ field in Boro 2021-22 season. As a result National Seed Board (NSB) approved this variety for commercial cultivation in the Boro season (dry season) in 2022. It has modern plant type with 92 cm plant height and matures by 147 days. The proposed variety showed 0.68 t/ha higher yield than check variety BRRI dhan50. Identifying characters of this variety are green leaf, intermediate plant height, erect flag leaf, long slender grain, and intermediate leaf senescence. In average, it can produce 7.30 t/ha grain yield but it has potentiality to give 8.71 t/ha grain yield under favorable climatic condition and appropriate agronomic management. Thousand grain weight of the variety is 21.5 gm and head rice yield is 57.2%. It is strong aromatic basmati type rice variety (according to GCMS system the value of volatile aromatic compound is 2.12 ppm), 29.2% amylose content with 8.9% protein content. Farmers can benefit financially from growing the premium quality enriched aromatic rice variety BRRI dhan104 and the total rice production will be increased along with possible to earn foreign currency by export this variety. Among the released variety by BRRI, the BRRI dhan104 is the only variety of aromatic basmati type.

Effect of soil and water salinity on dry season boro rice production in the south-central coastal area of Bangladesh

Salinity varies with location and time of the year. It can significantly impact crop production. The level of negative impacts depends on the salt concentration and time of its occurrence, which, however, has not been studied for many crops, especially for rice grown in the coastal area of Bangladesh. Our study explored the impact of spatio-temporal fluctuations in soil and water salinity on boro rice production in the south-central coast of Bangladesh. Here, we simulated the soil salinity from November 2020 to May 2021 for fourteen locations classes using the SWAP-WOFOST model. The model was calibrated and validated with measured secondary data. Next, the yield of two salt-tolerant boro rice varieties (BRRI dhan47 and BRRI dhan67) was simulated using the customized soil, weather, and crop data. We also simulated the yield by adopting agronomic management practices (i.e., changing planting time and using fresh irrigation water). Our results showed that salinity levels varied with different soil textural classes, soil depth, location, and time of the year, and that had a significant influence on boro rice production, giving spatial variability. Specifically, boro rice had a higher yield in coarse texture soil than in fine texture soil. Simulated yields in areas proximate to the sea ranged from 668 to 1239 kg ha−1, yields that are significantly lower than those simulated in moderate (2098–4843 kg ha−1) and low salinity zones (4213–4843 kg ha−1). Moreover, the simulation of yield with sowing/planting rice earlier by fifteen days provided a higher yield than the current planting practice since it could avoid salinity at later stages of growth. For a similar reason, growing rice inside the polder provided a higher yield than outside the polder. The insights gained from our study carry significant implications for contemporary crop-level adaptation strategies and policy-making in coastal districts.

Application of vermicompost to boro rice (BRRI dhan 28) can save phosphate fertilizer with sustaining productivity and soil fertility

Application of vermicompost to boro rice (BRRI dhan 28) can save phosphate fertilizer with sustaining productivity and soil fertility

Study on financial assessment of rice production causing false smut disease of different varieties at farm level in Kushtia district

The present study was conducted to evaluate the false smut incidence and its effect on yield in different varieties, and to determine the financial cost, return and profitability of rice production during the year 2018–2019 in Kushtia district. The highest average farmers (65%) lost their yield 0.85 t/ha in 5 severity scale of BRRI dhan49, while Dhani Gold as hybrid variety exerted the lowest yield losses of 0.20 t/ha in 7% affected farmers. Spraying of Nativo (75 WG) 0.40 kg/ha increased the yield 34.87% over control, and Amister Top 325 SC was applied in the field that produced lower yield compared to Nativo. Tilt (250 EC) 0.45 l/ha and Folicur 0.90 l/ha also showed significant increase of yield over untreated control plot. The highest gross return of BRRI dhan39 was determined at Tk. 114753/ha with higher price and its fine quality. The lowest gross return and net return were estimated at Tk. 106958/ha and (−) Tk. 1215/ha, respectively, in Shorna cultivar due to higher incidence of false smut disease.

Molecular Mapping to Discover Reliable Salinity-Resilient QTLs from the Novel Landrace Akundi in Two Bi-Parental Populations Using SNP-Based Genome-Wide Analysis in Rice

Achieving high-yield potential is always the ultimate objective of any breeding program. However, various abiotic stresses such as salinity, drought, cold, flood, and heat hampered rice productivity tremendously. Salinity is one of the most important abiotic stresses that adversely affect rice grain yield. The present investigation was undertaken to dissect new genetic loci, which are responsible for salt tolerance at the early seedling stage in rice. A bi-parental mapping population (F2:3) was developed from the cross between BRRI dhan28/Akundi, where BRRI dhan28 (BR28) is a salt-sensitive irrigated (boro) rice mega variety and Akundi is a highly salinity-tolerant Bangladeshi origin indica rice landrace that is utilized as a donor parent. We report reliable and stable QTLs for salt tolerance from a common donor (Akundi) irrespective of two different genetic backgrounds (BRRI dhan49/Akundi and BRRI dhan28/Akundi). A robust 1k-Rice Custom Amplicon (1k-RiCA) SNP marker genotyping platform was used for genome-wide analysis of this bi-parental population. After eliminating markers with high segregation distortion, 886 polymorphic SNPs built a genetic linkage map covering 1526.5 cM of whole rice genome with an average SNP density of 1.72 cM for the 12 genetic linkage groups. A total of 12 QTLs for nine different salt tolerance-related traits were identified using QGene and inclusive composite interval mapping of additive and dominant QTL (ICIM-ADD) under salt stress on seven different chromosomes. All of these 12 new QTLs were found to be unique, as no other map from the previous study has reported these QTLs in the similar chromosomal location and found them different from extensively studied Saltol, SKC1, OsSalT, and salT locus. Twenty-eight significant digenic/epistatic interactions were identified between chromosomal regions linked to or unlinked to QTLs. Akundi acts like a new alternate donor source of salt tolerance except for other usually known donors such as Nona Bokra, Pokkali, Capsule, and Hasawi used in salt tolerance genetic analysis and breeding programs worldwide, including Bangladesh. Integration of the seven novel, reliable, stable, and background independent salinity-resilient QTLs (qSES1, qSL1, qRL1, qSUR1, qSL8, qK8, qK1) reported in this investigation will expedite the cultivar development that is highly tolerant to salt stress.

The Study on Genetic Variability and Heritability in F4 Population of Rain-fed Rice (Oryza sativa L.)

Population establishment, selection, and evaluation are key components of plant breeding program. This study was designed to observe the genetic variability and the heritability of the selected yield component traits in F4 rice population. A field experiment was carried out with 16 F4 materials and 4 check varieties of Oryza sativa L. at Sher-e-Bangla Agricultural University, Dhaka to identify the suitable traits for the augmentation of rice yield. The F4 populations obtained from BR21×BR26, BR21× BRRI dhan28, BR 21× BRRI dhan29, BR24× BRRI dhan29, BR24× BRRI dhan36, BR26× BRRI dhan36 were utilized as breeding materials. Nine characters were considered i.e., days to 50% flowering, 80% maturity, plant height, tiller per panicle, panicle length(cm), filled grain per panicle, yield per plant(g), thousand-grain weight(g) and yield (t/ha). The selected genotypes were found significantly variable for all of the characters. The lowest days to maturity (92.00 days) were observed in G11 (BR21 × BRRI dhan29, F4, S7P2) following as G4 (BR21 × BRRI dhan29, F4, S1P2) (95.33 days) and G5 (BR21 ×BRRI dhan29, F4, S1P5) (96 days). The highest yield among F4 population was recorded in G6 (BR21 × BRRI dhan29, F4, S6P3) (6.08 t/ha) followed by G10 (BR21× BRRI dhan29, F4, S7P1) (5.30 t/ha) and G7 (BR21 × BRRI dhan29, F4, S6P8) (4.68ton/ha). All the traits showed remarkably higher phenotypic variances than the genotypic variances. Besides, all characters showed high heritability and higher PCV than the GCV. High heritability along with moderate to high genetic advance in percent mean is controlled by additive gene action which is better for selection. Int. J. Appl. Sci. Biotechnol. Vol 11(2): 99-105.

Influence of seedling age and integrated nutrient management on growth and yield of aromatic rice (cv. BRRI dhan34)

To investigate the performance of aromatic rice (cv. BRRI dhan34) in response to seedling age and nutrient management, an experiment was carried out at the Sher-e-Bangla Agricultural University, Dhaka from July to December 2021. The experiment includes three different ages of seedlings to be transplanted viz., 30, 45 and 60 days old and six nutrient management practice viz. control (no manures and fertilizers), recommended dose of inorganic fertilizers (RDF), 50% of RDF + cow dung @ 5 t ha-1, 75% of RDF + cow dung @ 5 t ha-1, 50% of RDF + poultry manure @ 2.5 t ha-1 and, 75% of RDF + poultry manure @ 2.5 t ha-1. The experiment was laid out in a randomized complete block design with three replications. The results revealed that in the case of transplanting of different aged seedlings, the highest leaf area index (5.74), dry matter hill-1 (32.86 g), number of tillers hill-1 (13.17), number of effective tillers hill-1 (11.53), plant height (113.34 cm), total grains panicle-1 (135.14), 1000-grain weight (12.45 g), grain yield (3.29 t ha-1), straw yield (4.01 t ha-1), biological yield (7.30 t ha-1) and were recorded from transplanting 30 days old seedlings. Different levels of nutrient management showed a significant impact on most of the parameters under study. The highest total dry matter hill-1 (34.02 g), the maximum LAI (5.35), plant height (115.70 cm), chlorophyll content (42.87), number of effective tillers hill-1 (12.99), panicle length (24.63 cm), total grains panicle-1 (140.17), 1000-grain weight (12.54 g), grain yield (3.27 t ha-1), straw yield (4.15 t ha-1), biological yield (7.42 t ha-1) and harvest index (43.03%) were also recorded in F5 (75% of RDF + poultry manure @ 2.5 t ha-1) treatment. While considering the interaction effects between the age of seedlings and nutrient management, transplanting 30 days old seedlings along with the nutrient management of 75% of RDF + poultry manure @ 2.5 t ha-1 treatment improved yield contributing parameters and provided the highest yield (3.76 t ha-1) of BRRI dhan34 compared to other treatment combination. So, the application of 75% of RDF + poultry manure @ 2.5 t ha-1 along with 30 days old seedlings appeared as a promising practice to obtain better performance of fine aromatic rice (cv. BRRI dhan34).

Maximizing yield of aromatic fine rice through application of zinc and poultry manure

Zinc (Zn), one of the most important micronutrients for plants which play vital role in various metabolic functions and deficiency of this nutrient in agricultural soils associated with lower yield of rice in many regions of the world. The integrated use of organic and inorganic fertilizer has been found to be promising for sustainable crop production and poultry manure could be a rich source of organic matter. Considering these factors, a field experiment was conducted to observe the effect of zinc and poultry manure-based fertilization on the yield of aromatic fine rice, BRRI dhan34. Four levels of zinc and three levels of poultry manure (PM) were tested as treatment including control. Application of zinc, PM and their interaction significantly influenced the growth and yield of rice that result the tallest plant (131.33 cm), maximum number of effective tillers/hill (13.89), grains/panicle (128.54), 1000-grain weight (12.09 g) and highest grain yield (3.21 t/ha) where 4 kg Zn/ha were applied. On the other hand, tallest plant (129.92 cm), maximum number of effective tillers/hill (9.13), grains/panicle (128.23), 1000-grain weight (12.05) and grain yield (3.24 t/ha) were obtained where 10 t/ha of PM were applied. The interaction between application of 4 kg Zn/ha and 10 t PM/ha performed best in all yield contributing characters and results maximum grain yield (3.64 t/ha). Therefore, 4 kg Zn/ha along with 10 t PM/ha was found to be suitable combination for cultivation of aromatic fine rice.

Variations in Root Morphology and Yield among Rice Varieties in Response to Potassium under Subtropical Conditions

The relationship between rice root morphology and Potassium (K) is a major concern for its growth and development, and it has a substantial impact on yield as well. In light of this, the current pot research was run in the net house of the Department of Agronomy at the Bangladesh Agricultural University, Mymensingh, Bangladesh, throughout the boro (dry season irrigated) season of 2020–2021. Binadhan-10, Hira-2 and BRRI dhan29 were grown with five K fertilizers: 0 kg K ha−1 (K0), 32 kg K ha−1 (K32), 65 kg K ha−1 (K65), 98 kg K ha−1 (K98) and 130 kg K ha−1 (K130). Three replications of the investigation were conducted using a completely randomized design (CRD). The root number (RN), root length (RL), root volume (RV), root porosity (RP) along with leaf area index (LAI), total dry matter (TDM) and yield were assessed. Binadhan-10 with the K65 treatment significantly increased the RN, RL, RV, LAI, TDM and yield. With the further increase in the dosage of K that was under K98 and K130, the value of the root traits and yield did not increase. A positive connection was documented between the grain yield (GY) and all the root traits, excluding the RP. Binadhan-10 can be grown with 65 kg K ha−1 at field level for a satisfactory yield.

Plant Growth Promoting Rhizobacteria (PGPR) Increases Yield and Mineral Contents of Rice by Mobilizing Nutrients in the Rhizosphere

Plant growth-promoting rhizobacteria (PGPR) are multipurpose entities in case of crop quality and yield improvement. This study evaluated the impact of PGPR inoculation in root zone nutrient release, rice yield, and grain nutrient (P, Fe, Mn, and Zn) content in two popular rice varieties of Bangladesh (viz., BRRI dhan49 and Binadhan7). It was a single factor (bacterial treatment) experiment where B0, B1, B2, and B3 treatments represented the inoculated control, indole acetic acid (IAA) producing bacteria consortium, phosphorus solubilizing bacteria (PSB) consortium, and combination of B1 and B2 treatments, respectively. Nutrients released in pore water was higher at 5 days after transplanting (DAT), compared to 25 DAT. Mostly B2 and B3 treatments performed significantly in the number of tillers/pots, straw yield, grain yield, grain P, Mn, Fe content, and all four nutrients uptake. The highest grain yield observed in B3 treatment is in both Binadhan7 (42.10±1.76 g/pot) and BRRI dhan49 (36.20±1.57 g/pot). PSB containing B2 treatment bio-fortified the largest amount of P in both rice varieties. On the other hand, the B3 treatment stored the highest amount of Mn (46.70±1.30 and 44.30±1.37 mg/kg) and Fe (45.30±2.90 and 25.70±2.37 mg/kg) in Binadhan7 and BRRI dhan49, respectively. The B3 treatment resulted in maximum nutrient content (P, Mn, and Fe) and uptake (P, Mn, Fe, and Zn) in both rice varieties. These bacterial isolates seemed promising for rice yield and quality improvement in an eco-friendly and sustainable way. Res. Agric. Livest. Fish. 10(1): 73-81

Effect of Exogenous Salicylic Acid and Silicon Application on Salinity Tolerance of Rice

Soil salinity remarkably hinders rice growth, development and productivity. The present study was set up to explore the role of exogenous salicylic acid (SA) and silicon (Si) application on the growth and yield performance of two contrasting rice genotypes, namely BRRI dhan41 (salt-tolerant) and BRRI dhan49 (salt-sensitive) under salinity. The experiment was laid out in a randomized complete block design with three replications and four SA and Si treatments such as control (tap water), 100 ppm SA, 100 ppm Si (as CaSiO3) and, co-application of SA and Si (50 ppm each). Results revealed that the maximum plant height (125.2 cm), fresh weight of shoot (267.3 g) and maximum K+/Na+ (5.2) were obtained in BRRI dhan49 after sole application of Si under salt stress. Besides, the number of grains per panicle and grains per hill significantly increased in BRRI dhan41 after the sole application of SA (64 and 46%, respectively) and co-application of SA and Si (29 and 21%, respectively), and in BRRI dhan49 with sole SA (182 and 277%, respectively) and Si (75 and 446%, respectively) compared with their respective controls. Besides, we observed that the K+/Na+ was increased where the shoot accumulation of Na+ reduced significantly in both rice varieties after sole and co-application of SA and Si compared with the untreated plants. However, the present findings showed new dimensions regarding the beneficial effects of Si on rice plants which could effectively be utilized to grow and maximize rice production in the saline-prone coastal areas of Bangladesh encountering detrimental effects of salt stress on rice.
 Bangladesh Agron. J. 2022, 25(2): 119-127

Growth and Yield Response of Selected Aman Varieties as Influenced by Leaf Cutting

Sustainable crop production in the era of increasing input price is adding extra burden while the cultivable land is reducing at an alarming pace. This research article aims to test the hypothesis that the leaf cutting as an agronomic practice could be a better prospective in increasing rice grain production. An experiment was carried out in the experimental field of Sher-e-Bangla Agricultural University, to assess the effect of leaf cutting on plant growth and yield of selected BRRI released Aman varieties. The experiment consisted of five rice varieties namely BRRI dhan32, BRRI dhan33, BRRI dhan39, BRRI dhan62, and BRRI dhan56 treated either as control or leaf cutting (except flag and penultimate leaf). The experiment was laid out in randomized complete block design (RCBD) with three replicates. Leaf cutting was observed with detrimental effect on the usual plant growth and yield performances. Irrespective of all studied varieties, the highest value was obtained while no leaf cutting was performed. BRRI dhan39 was found to be the highest yield producing variety in terms of greater flag leaf length, leaf breadth, flag leaf area, required less time to grain filling, filled grain panicle-1, filled grain%, 1000-grain weight, grain yield and harvest index in leaf cutting condition followed by BRRI dhan32 in terms of plant height, chlorophyll content, tiller hill-1 and straw yield. No significant differences in yield contributing parameters except the panicle hill-1 were observed in leaf cutting condition compared to control. Leaf cutting at heading (except flag leaf and penultimate leaves) reduced average 10-20% loss of grain yield. BRRI dhan62 shown highly affected by leaf cutting compared to the rest other varieties. Therefore, it can be concluded by suggesting that leaf cutting reduces plant functional efficiency which can be improved by enhancing photosynthetic capacity through proper management of leaf architecture.
 Bangladesh Agron. J. 2022, 25(2): 1-9

Effects of Irrigation Regimes and Rice Varieties on Methane Emissions and Yield of Dry Season Rice in Bangladesh

Adoption of the right rice variety and water-saving irrigation method could reduce greenhouse gas (GHG) emissions in lowland rice cultivation. A study was conducted at the research farm of Bangladesh Agricultural University, Mymensingh, Bangladesh, in 2019 during the Boro (dry) season to determine the impacts of different rice varieties (BRRI dhan29, BRRI dhan47, BRRI dhan69, Binadhan-8, Binadhan-10, and Binadhan-17) on methane (CH4) emissions under two irrigation methods, i.e., alternate wetting and drying (AWD) and continuous flooding (CF). The treatments were laid out in a split-plot design, considering water regime as the main plots and rice variety as the sub-plots. The emission rates of CH4 were determined by collecting air samples using the closed chamber technique and measuring the concentrations using a gas chromatograph. CH4 emission rates varied with the growth and development of the rice varieties. The lowest cumulative CH4 emission rate was observed in Binadhan-17, particularly under AWD irrigation. Across the rice varieties, AWD irrigation significantly reduced the cumulative CH4 emissions by about 35% compared with CF. No significant variation in rice yield was observed between AWD (5.38 t ha−1) and CF (5.16 t ha−1). This study suggests that the cultivation of Binadhan-17 under AWD irrigation could be effective at reducing the carbon footprint of lowland rice fields.

Assessment of Yield Limiting Nutrients through Response of Rice to Nutrient Omission Technique of Shallow Brown Terrace under Madhupur Tract

A field experiment was conducted during Boro 2018-2019 and T.Aman 2019 season at Bangladesh Rice Research Institute, Gazipur to assess the yield limiting nutrients and response of rice to nutrient omission technique for the Boro-Fallow-T. Aman rice cropping pattern. The experiment was set up in a split plot design (RCBD) with three replications. Four fertilizer treatments viz T1=NPK (AEZ basis), T2=N omission (-N), T3=P omission (-P) and T4=K omission (-K) were imposed in the main plots. The rice genotypes viz Nerica Mutant, BRRI dhan28 and BRRI dhan45 in Boro season and in T.Aman BRC245-4-19-2-1, BR11 and BRRI dhan31 was laid in the subplots. Interaction of nutrient omission and rice genotypes showed significant effect on all the tested growth attributes in Boro 2018-19 season. Treatments with ample dose (NPK) show significantly outperformed than N and P omission in respect of the plant height, tiller and panicle number per square meter but no significance differences of growth attributes were observed in case of K omission in Boro season. Varietal influence of different rice genotypes due to ample dose of NPK and their omissions were insignificant but significance influence of grain yield due to nutrient omission was found. Due to P omission, highest yield reduction (80%, BRRI dhan45) was recorded in Boro season. In T.Aman Season, Only N omission significantly produced lowest tiller and panicle number per meter square. Less than 25% of yield reductions due to nutrient omission were recorded in T.Aman season. The overall findings of the study point out that the yield limiting nutrients in Boro season were identified as N and P. However, N and K was found yield limiting nutrient factor in T.Aman season.