http://localhost:8080/handle/123456789/2701 Thu, 09 Apr 2026 01:44:46 GMT 2026-04-09T01:44:46Z http://localhost:8080/handle/123456789/5154 ENHANCEMENT OF SALT TOLERANCE IN RICE THROUGH PLANT GROWTH-PROMOTING RHIZOBACTERIA SIDDIKA, AYESHA The ongoing expansion of global salt-affected land is a significant factor limiting crop growth and yield, particularly for rice. This experiment explores the mitigation of saltinduced damage on rice (Oryza sativa L. cv BRRI dhan100) by applying plant growthpromoting rhizobacteria (PGPR) cultures. This experiment followed a completely randomized design (CRD) and experimental duration was December 2022 to May 2023. where rice seedlings, five and six weeks post-transplanting, were subjected to salt stress via two treatments with 50 and 100 mM NaCl at seven-day intervals. Bacterial cultures, comprising endophytic PGPR strains (Bacillus subtilis and B. aryabhattai) and an epiphytic PGPR strain (B. aryabhattai), were administered at three critical stages: during transplantation of 42-d-old seedlings, five weeks later at the vegetative stage at 35 days after transplanting (DAT), and seven weeks later at 49 DAT during panicle initiation stage. Salt stress prompted osmotic, ionic, and oxidative stress in rice plants, causing a dose-dependent decrease in relative water content, chlorophyll content, stomatal conductance, chlorophyll fluorescence, IAA concentrations, and various growth parameters. Furthermore, osmotic stress escalated the hydrogen peroxide content and proline accumulation, while ionic stress disrupted ion balance by increasing Na + and reducing K + content. Both types of stress generated reactive oxygen species, impairing the antioxidant defense system and causing oxidative damage, visible in heightened malondialdehyde levels and electrolyte leakage. PGPR treatment alleviated these negative effects by enhancing osmotic and ionic balance, demonstrated by improved water balance and reduced Na + content and Na + /K + ratio. Additionally, PGPR fortified the antioxidative defense system in salt-exposed rice plants by increasing ascorbate and glutathione levels. The introduction of PGPR led to enhancements in yield attributes (including effective tillers per hill, panicle length, rachis per panicle, filled grains per panicle, and 1000-grain weight), consequently boosting the grain yield per hill. In conclusion, this research highlights the potential of PGPR to bolster physiological and biochemical functionality in rice, serving as an effective buffer against salt stress-induced damage A thesis Submitted to the Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN AGRONOMY Sat, 01 Jan 2022 00:00:00 GMT http://localhost:8080/handle/123456789/5154 2022-01-01T00:00:00Z http://localhost:8080/handle/123456789/5131 INFLUENCE OF HERBICIDES ON GROWTH, YIELD AND CONTROLLING WEEDS IN DIRECT-SEEDED AUS RICE SEBA, MOST. ISRAT ZAHAN A field experiment was carried out at the Agronomy field of Sher-e-Bangla Agricultural University, Dhaka, Bangladesh, from March to August 2022, to investigate the efficiency of herbicides against weeds and influence on growth, yield and yield contributing parameters of direct-seeded rice aus rice of Bangladesh. The experiment consisted of 13 treatments viz., Unweeded (control), partial weeding (two-hand weeding at 20 and 40 Days After Sowing), weedfree, Butachlor (25 kg ha -1 ), Pendamethyline (2 L ha ii -1 ), Pretilachlor (1 L ha ), BispyribacSodium (25 g ha -1 ), Butachlor (25 kg ha -1 ) + Bispyribac-Sodium (25 g ha -1 ), Pendamethyline (2 L ha 1 -1 ) + Bispyribac-Sodium (150 g ha -1 -1 ), Pretilachlor 6% + Pyrazosulfuron- ethyl 0.15% (2 kg ha ), Pretilachlor 30% + Pyrazosulfuron- ethyl 0.75% (2 kg ha -1 ), Acitachlor 14% + Bensulfuron methyl 4% (3 kg ha -1 ), 2, 4-D Amine (2.24 L ha -1 ). The test rice variety was BRRIdhan 98. The experiment was laid out in a randomized complete block design having 3 replications. Seeds were sown directly on 29 March 2022. Seventeen weed species infested the experimental field belonging to 10 families, where the most dominating were broadleaf and grass weed species. Among the weeds, Digitaria ischaemum was the most dominant weed at 20, 40, and 60 DAS, followed by Physalis heterophylla and Digitaria sanguinalis. The sequential application of Pendimethalin and Bispyribac-Sodium herbicides treated plots recorded minimum weed density m -2 (0.0, 2.33, and 4.00) and weed dry weight (0.00, 0.57, and 1.25 g) at 20, 40, and 60 DAS, respectively. The highest weed control efficiency (100, 88.46 and 80.66 %) at 20,40 and 60 DAS among all herbicidal treatments and also the highest weed control index (97.31 and 99.16%, respectively) at 60 and 90 DAS. Among the weed management practices weed-free and partial weeding notably reduced the weed counts, higher growth and yield attributes and grain yields. It was statistically at par with applying Pendamethyline (2 L ha -1 ) followed by Bispyribac-Sodium (25 g ha -1 ), which ultimately gave the highest grain yield was obtained from weed free treatment followed by partial weeding. But from economic view of point, partial weeding and Pendimethalin + Bispyribac-sodium showed almost similar benefit-cost ratio.Therefore, Pendamethyline (2 L ha -1 ) and Bispyribac-Sodium (25 g ha -1 ) were found as the best broadspectrum effective herbicides to manage the various weed flora in direct-seeded aus rice. A Thesis Submitted to the Faculty of Agriculture Sher-e-Bangla Agricultural University, Dhaka, in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN AGRONOMY Sat, 01 Jan 2022 00:00:00 GMT http://localhost:8080/handle/123456789/5131 2022-01-01T00:00:00Z http://localhost:8080/handle/123456789/5130 INFLUENCE OF SEEDLING LEAF CLIPPING AND PLANT SPACING ON GROWTH AND YIELD OF BRRI Dhan80 HOSSAIN, MD. SAGAR A field experiment was conducted at Sher-e-Bangla Agricultural University, Dhaka during the Aman season of June to November 2021, to the study influence of seedling leaf clipping and plant spacing on growth and yield of BRRI dhan80. The experiment was consisted of two factors, and followed Randomized Complete Block Design with three replications. The factors were as Factor A: Seedling leaf clipping (3) viz; C = No seedling clipping, C 1 = Top 1/3 rd portion clipping, C 2 = Top 1/2 nd portion clipping and Factor B: Different plant spacing (4) viz; S 1 = 25 cm × 25 cm, S 2 = 25 cm × 20 cm, S = 20 cm × 20 cm and S = 20 cm × 15 cm. Experimental results revealed that, growth and yield of aromatic rice significantly influenced due to seedling leaf clipping. The highest panicle length (23.79 cm), filled grains panicle 4 -1 (130.52), 1000-grain weight (24.43 g), grain yield (4.59 t ha -1 ), straw yield (5.99 t ha -1 ), biological yield (10.58 t ha ) and harvest index (43.29 %) were observed from C (No seedling clipping) treatment. In the case of different plant spacings, the highest panicle length (24.01 cm), filled grains panicle -1 0 (134.10) and 1000-grain weight (24.82 g) were observed in S (25 cm × 25 cm) treatment. However, the highest grain yield (4.61 t ha -1 1 ), straw yield (6.04 t ha ), biological yield (10.66 t ha -1 ) and harvest index (43.22 %) were observed in S (20 cm × 15 cm) treatment. In the case of treatment combination, C 0 S (No seedling clipping along with 20 cm × 15 cm plant spacing) gave the highest grain yield (5.11 t ha 4 ), straw yield (6.32 t ha -1 ), biological yield (11.42 t ha -1 ) and harvest index (44.71 %) whereas the lowest of these values were observed from C 2 S 1 combination (Top 1/2 nd portion seedling clipping along with 20 cm × 15 cm plant spacing). Based on the above findings, it would be considered that no seedling leaf clipping treatment along with 20 cm × 15 cm plant spacing (C 0 S ) would be helpful to enhance better grain yield production of BRRI dhan80. A Thesis Submitted to the Faculty of Agriculture Sher-e-Bangla Agricultural University, Dhaka, in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN AGRONOMY Sat, 01 Jan 2022 00:00:00 GMT http://localhost:8080/handle/123456789/5130 2022-01-01T00:00:00Z http://localhost:8080/handle/123456789/5129 ROLE OF ORGANIC AMENDMENTS ON MORPHOPHYSIOLOGY OF RICE UNDER ARSENIC STRESS KHATUN, MST. MAHBUBA Our study investigated the arsenic induced stress of morpho-physiology in rice plant and the role of organic amendments; cowdung, vermicompost, biochar to mitigate the damages. Rice seedling was grown in 18L pot with 4 arsenic treatment at 21DAT, 32DAT, 42DAT and 52DAT. Sodium Arsenate (0.5Nm, Na 2 HAsO 4 ) considered as As 1 and Sodium (meta) arsenite (0.5Mm, NaAsO 2 ) considered as As 2 and 1.5kg cow-dung, 600g vermi-compost and 500g biochar used as protectant. Plant height, leaf number, leaf area, tiller no. hill , chlorophyll content data are collected from 35DAT to 49 DAT with 7 or 15days interval. Relative water content, shoot and root fresh weight and dry weight data are recorded at 42DAT. The highest plant height was found at control condition at 35DAT, 42DAT and 49DAT. In case of As 1 at all the DAT, vermicompost shows the highest result of plant height and in As 2 condition biochar shows the highest plant height. Also these amendments increased the fresh and dry weight of shoot and root of rice plants. All parameters decreased significantly at 0.5 mM of arsenic stress. For both As 1 and As 2 treated plants combined with vermicompost and biochar shows an increasing percentage at all the yield contributing data parameters compare to As 1 and As 2 treated plant only. Our experiment concludes that rice plant under arsenic stress, vermicompost shows the better percentage of increasing result when plant expost to As 1 (0.5 mM; Sodium arsenate, Na 2 HAsO 4 ) and in case of As 2 (0.5 mM; Sodium meta arsenite, NaAsO 2 ) biochar shows an increasing result compare to all the treatments A Thesis Submitted to the Faculty of Agriculture Sher-e-Bangla Agricultural University, Dhaka, in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN AGRONOMY Sat, 01 Jan 2022 00:00:00 GMT http://localhost:8080/handle/123456789/5129 2022-01-01T00:00:00Z