BRRI Dhan29 Research Articles

Seed Quality of Transplanted Aman Rice as Impacted by Rainfed in the Ripening Phase

Rainfall is the main contributor to provide soil moisture for rainfed rice (Transplanted Aman) cultivation. The aim of the study was to investigate the seed quality of different transplanted Aman rice cultivars that are influenced by rainfed during ripening phases. For this, several experiments have been performed during the transplanted Aman season of 2014, 2015, and 2016 at the Bangladesh Rice Research Institute, Gazipur. Two planting dates and three rice varieties were used in the treatment, and the treatments were organized in a randomized complete block design with three replications. T. Aman rice received huge rainfall up to vegetative phage resulting no irrigation demand in all three tested years. In all the parameters of yield and yield components, the association between planting dates and variety was not significant. Also the relationship between planting dates and variety did not greatly affect the germination percentage, seedling vigor index, high density grain shoot dry weight, and root dry weight. Sixteen august planting produced a greater number of tillers m-2, panicles m-2, grain panicle-1, 1000-grain weight, grain and straw yield in the case of yield and yield components. While, the 1000-grain weight of panicles m-2, grain panicle-1, was greatly influenced by the variety. The highest 1000 grain weight and grain yield were produced by BRRI dhan46. The SVI, HDG percent, SDW and RDW were greatly influenced by planting dates in terms of seed quality. All of these criteria were higher for planting on 16 August than for planting on 12 September. Early transplanting received more rainfall in reproductive phase than late planting. Varieties were greatly influenced by all the seed quality parameters. BRRI dhan46 received the highest GM percent, SVI, HDG percent, SDW and RDW. Specific suitable transplanting dates were selected considering minimum irrigation at reproductive phage and maximun seed quality and grain yield. Delay in transplanting demanded more irrigation and reduced seed quality and grain yield.

A Comparative Study on Hybrid and Inbred Rice Grown in Aman Season

This experiment was conducted at the experimental field of Sher-e-Bangla Agricultural University, Dhaka during the period from July to December, with a view to finding out the growth and yield performance of selected hybrid and inbred rice varieties in Aman season. There were seven treatments which comprised seven rice varieties viz. Gold-5, BRRI dhan56, BRRI dhan57, BRRI dhan62, Suborna-3, BRRI hybrid dhan4 and Moyna. The experiment layout was RCBD with three replications. Seedling of 25 days old was transplanted to the main field maintaining spacing with 25 cm X 15 cm. The plot size was 3X3m2. Collected data were analyzed with statistix10 software following the standard procedure and method. Significant variation was found among the selected inbred and hybrid rice varieties in respect of their different growth and yield characters. All the hybrid varieties contained higher amount of chlorophyll in their flag leaf at flowering to maturity compared to the inbred. BRRI hybrid dhan4 showed superiority over the hybrid and inbred varieties in different growth parameters. BRRI hybrid dhan4 also showed superiority in case of yield parameters such as panicles (14.27), filled grains panicle-1(168.43), 1000-grain weight (26.07 g), biological yield (13.33 t ha-1) and grain yield (6.13 t ha-1). Rest of the hybrid varieties viz. Shuborna 3 (5.60 t ha-1), Gold (5.15 t ha-1) and Moyna (4.86t ha-1) also provided higher grain yield compared to BRRI dhan56 (4.63 t ha-1) and BRRI dhan57 (4.25 t ha-1). Panicles hill-1, filled grains panicle-1 and 1000 grain weight mainly contributed to the higher grain yield of the hybrid varieties over the inbred.

Effect of municipal solid waste compost and NPK fertilizer on growth, yield and protein content of rice (cv. BRRI dhan49)

An experiment was conducted to study the effect of municipal solid waste compost (MSWC) on growth, yield and protein content as well as to know the effect of combined application of MSWC and NPK fertilizers in rice (cv. BRRI dhan49). There were six treatments including- T0 = Control (No fertilizer or no MSWC); T1= 100% Recommended Doses of Fertilizers (RDF) NPK; T2 = (MSWC @ 5 t ha-1+ 75% RDF); T3= (MSWC @ 7. 5t ha-1+ 50% RDF); T4= (MSWC @ 10 t ha-1 + 25% RDF); T5 = (MSWC @ 10 t ha-1). The experiment was laid out in a randomized complete block design (RCBD) with three replications. Our results showed that the integrated application of MSWC and different RDF% had a significant impact on various plant growth and yield parameters including plant height, panicle length, number of effective tillers per hill, number of filled grains per panicle, 1000-grain weight (g), and grain and straw yield of rice. In case of T2 treatment, highest grain yield (5.70 t ha-1), straw yield (7.71 t ha-1) and protein content (5.875%) were obtained. Thus, the result indicated that combined application of MSWC with NPK performed better than the single application of either MSWC or NPK fertilizer.

Comparative studies on tolerance of two rice genotypes differing in their salinity tolerance

Salinity is a serious problem affecting one third of the irrigation land and limiting the yield potential of modern rice (Oryza sativa L.) varieties. To increase our understanding of salt tolerance mechanisms in rice for better production, knowledge of salinity effects on rice seedling growth and yield components is inevitable. Despite of large number of studies on salinity tolerance of rice, we have very limited knowledge on the overall effect of salinity on rice seedlings growth. The experiment was carried out to assess the responses of salinity on the growth, nutrient accumulation and yield of rice genotypes BRRI dhan29 (salt-sensitive) and BINA dhan-10 (salt-tolerant). The pot experiment was conveyed at the net house to evaluate the response of two rice genotypes at five levels of salt stresses (0, 25, 50, 75, 100 mM NaCl) at the vegetative stage. After harvesting of rice, electrical conductivity of soil was analyzed. Growth, yield components, grain and straw yields were evaluated. Binadhan-10 showed a higher salt tolerance in physiological parameters of rice than BRRI dhan29. A significant reduction of growth, yield components, grain and straw yields of both rice genotypes was found in response to salt stress. At different salt stress conditions nutrient uptake (NPS) and K+/Na+ ratio was significantly decreased in both rice genotypes. Yet, K+/Na+ ratio was more in salt-tolerant variety than salt-sensitive variety. Asian J. Med. Biol. Res. 2022, 8 (4), 230-239

Exogenous Gallic Acid Confers Salt Tolerance in Rice Seedlings: Modulation of Ion Homeostasis, Osmoregulation, Antioxidant Defense, and Methylglyoxal Detoxification Systems

The worldwide saline-affected area is expanding day by day, and soil salinity restricts crop development and productivity, including rice. Considering this, the current study explored the response of gallic acid (GA) in conferring salinity tolerance in rice seedlings. Fourteen-day-old rice (Oryza sativa L. cv. BRRI dhan52) seedlings were treated with 200 mM NaCl alone or combined with 1 mM GA. Salt stress resulted in osmotic, ionic, and oxidative stress in rice seedlings. Osmotic stress increased proline accumulation and osmotic potential, which decreased the relative water content, chlorophyll contents, and dry weight. Ionic stress interrupted ion homeostasis by Na+ accumulation and K+ leakage. Osmotic and ionic stress, concomitantly, disrupted antioxidant defense and glyoxalase systems by higher production of reactive oxygen species (ROS) and methylglyoxal (MG), respectively. It resulted in oxidative damage indicated by the high amount of malondialdehyde (MDA). The supplementation of GA in salt-treated rice seedlings partially recovered salt-induced damages by improving osmotic and ionic homeostasis by increasing water balance and decreasing Na+ content and Na+/K+ ratio. Supplemental GA enhanced the antioxidant defense system in salt-treated rice seedlings by increasing ascorbate (AsA), glutathione (GSH), and phenolic compounds and the activities of AsA-GSH cycle enzymes, including monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and glutathione reductase (GR) enzymes that accelerated ROS detoxification and decreased oxidative damage. Gallic acid also enhanced the detoxification of MG by triggering glyoxalase enzyme activities in salt-treated rice seedlings. The present findings elucidated that supplemental GA reversed salt-induced damage in rice seedlings through improving osmotic and ionic homeostasis and upregulating the ROS and MG detoxification system.

Performance of different conservation practices for irrigated paddy rice (Oryza sativa) cultivation as affected by soil texture of Mymensingh region in Bangladesh

Soil moisture is critical to the growth and yield-contributing character traits of rice. However, few studies have yet to outline the effects of soil texture on irrigated paddy rice cultivation under diverse conservation techniques. In this regard, an experiment was conducted at the Field Irrigation Laboratory of Bangladesh Agricultural University to investigate the water productivity and yield-contributing characteristics of paddy rice (Oryza sativa L.; variety: BRRI dhan 28) during Boro season for two years with two different soil textures (silt loam, 2019 and loam, 2020) and three different irrigation techniques, namely, Alternate Wetting and Drying (AWD), Raised Bed (RB) and the conventional Continuous Flooding (CF). It was observed that seepage in CF treatment was higher than that of AWD and RB. Highest grain yield (6.70±0.04 t/ha) was found for 15 cm AWD treatment (irrigation applied when water level reached 15 cm below ground surface) for silt loam and the same for loam soil was 6.53±0.50 t/ha under 10 cm AWD treatment. CF method of irrigation yielded grain lowest for both silt loam (5.47±0.05) t/ha and loam (5.28±0.19) t/ha soil. For both soil textures, CF treatment required more water than conservation treatments and resulted in lower water productivity. Again, for both the types of soil, AWD performed comparatively better than the CF, especially 15 cm AWD for silt loam soil and 10 cm AWD for loam soil because it required minimum water for paddy rice cultivation and its water productivity was maximum for the same rice production. Therefore, adopting these water-conserving methods would have a considerable implication for water-scarce agricultural regions.

Development of Potato-Boro-T. Aman Rice Cropping Pattern Against Fallow-Boro-T. Aman Rice Cropping Pattern at Mymensingh

The experiment was conducted at Multiplication Testing Site (MLT) Trishal of On-Farm Research Division, Bangladesh Agricultural Research Institute, Mymensingh during 2017-18 and 2018-19 to evaluate the agro-economic performance of improved cropping pattern for increasing cropping intensity and system productivity as compared to farmers’ existing cropping pattern. The experiment was laid out in randomized complete block design with six dispersed replications. Two cropping patterns viz. improved pattern Potato (BARI Alu- 25)-Boro (BRRI dhan28)-T. Aman rice (BRRI dhan49) and farmers existing cropping pattern Fallow-Boro (BRRI dhan29)- T. Aman rice (BRRI dhan49) were treatments variables of the experiment. Two years mean data showed that Potato-Boro-T. Aman rice cropping pattern produced higher tuber/grain yield as well as higher rice equivalent yield (30.53 t ha-1yr-1), production efficiency (149 kg ha-1 day-1), land utilization index (74 %) and labour employment (367mandays ha-1 yr-1) than Fallow-Boro-T. Aman rice cropping pattern. This pattern also increased system productivity, production efficiency, land utilization index and labour employment by 158, 166, 26 and 51% higher over exiting pattern. The mean gross return (Tk. 481800 ha-1) and gross margin (Tk.235329 ha-1) of improved cropping pattern were 139 and 237% higher, respectively compared to existing pattern with 87% extra cost. The mean marginal benefit cost ratio (2.45) indicated superiority to improved cropping pattern over existing pattern. Experimental findings revealed that there is potential for greater adoption of intensified cropping systems with increased productivity and profitability as compared to rice–rice systems in Mymensingh.
 Bangladesh J. Agril. Res. 45(3): 279-292, September 2020

Agroeconomic Performance of Maize in Zero Tillage As Relay and After Harvest of Transplanted Aman Rice

A field trial was conducted at the multi-location testing (MLT) site, Moulvibazar, Bangladesh during two consecutive years of 2017-2018 and 2018- 2019 located in Agro Ecological Zone (AEZ)-20; under Eastern Surma Kushiyara Floodplain to introduce maize in zero tillage as relay and after harvest of T. aman rice. Four sowing dates of maize seed viz. T1: 10 November as relay with T. aman rice, T2: 20 November as relay with T. aman rice, T3: 30 November in T. aman harvested fallow land and T4: 10 December in T. aman harvested fallow land were used as treatment variables. The trial was laid out in a randomized complete block design with three replications. Maize var. BARI Hybrid Maize-9 and short duration T. aman rice var. BRRI dhan56 /BRRI dhan57 were used. Sowing time is critical for maximizing yield for both grain and biomass yield of maize. Yield and yield attributes of maize varied significantly due to different sowing dates. The result showed that grain yields of maize 8.48, 11.20, 8.22 and 7.98 t ha-1 were achieved with seed sown on 10 November as relay with T. aman rice, 20 November as relay with T. aman rice, 30 November in T. aman harvested fallow land and 10 December in T. aman harvested fallow land, respectively. The highest grain yield (11.20 t ha-1) was obtained when sowing on 20 November as relay with T. aman rice, which showed an increase of grain yield of 40, 36 and 32 % than 10 December in T. aman harvested fallow land, 30 November in T. aman harvested fallow land and 10 November as relay with T. aman rice, respectively. The highest gross return (Tk. 2,30,095 ha-1), net return (Tk. 1,33,845 ha-1) and benefit cost ratio (2.39) were noted in the same treatment indicated the profitability of maize in zero tillage as relay with T. aman rice in AEZ 20.
 Bangladesh J. Agril. Res. 45(3): 239-246, September 2020

Optimum Nitrogen Application Acclimatizes Root Morpho-Physiological Traits and Yield Potential in Rice under Subtropical Conditions

Nitrogen (N) is a highly essential macronutrient for plant root growth and grain yield (GY). To assess the relationship among N, root traits, and the yield of boro (dry season irrigated) rice, a pot experiment was performed in the Department of Agronomy, Bangladesh Agricultural University, Mymensingh, Bangladesh, during the boro rice season of 2020-2021. Three boro rice varieties, namely BRRI dhan29, Hira-2, and Binadhan-10, were planted at four N doses: 0 kg ha-1 (N0), 70 kg ha-1 (N70), 140 kg ha-1 (N140), and 210 kg ha-1 (N210). The experiment was conducted following a completely randomized design with three replicates. The varieties were evaluated for root number (RN), root length (RL), root volume (RV), root porosity (RP), leaf area index (LAI), total dry matter (TDM), and yield. The results indicated that the Binadhan-10, Hira-2, and BRRI dhan29 varieties produced better root characteristics under at the N140 and N210 levels. A substantial positive association was noticed between the grain yield and the root traits, except for root porosity. Based on the root traits and growth dynamics, Binadhan-10 performed the best at the N140 level and produced the highest grain yield (26.96 g pot-1), followed by Hira-2 (26.35 g pot-1) and BRRI dhan29 (25.90 g pot-1).

Temporal and spatial representation of temperature and moisture in drying chamber and its impact on vertical vacuum dehumidifying rice seed dryer performance

Population growth is resulting in a daily increase in rice consumption demand. To grow paddy for this expanding population, quality seeds are necessary. The study was conducted to evaluate the performance and estimate the drying cost of the vertical vacuum dehumidifying dryer. The studied dryer consists of four main parts: drying chamber, heating and cooling chamber, compressor and blower. The paddy (BRRI dhan 80) sample sizes were 100, 125 and 150 kg as treatment per batch. In three treatments, the drying chamber temperature was varied from 21.1 to 57.0 °C. Paddy was dried from initial moisture content 21.8 to 10.6%, 21.1 to 12.0% and 20.7 to 11.9% in three treatments within the drying time of 6.0, 6.5 and 7.0 hrs respectively. During the drying process, the relative humidity was differed from 60 to 35%. The rate of drying was found 2.08, 2.12 and 2.01 kghr −1 respectively for 100, 125 and 150 kg per batch. The capacities of the dryer were found 16.66, 19.23 and 21.43 kghr −1 for three treatments respectively. The drying efficiency was found 68.85% (for 100 kg batch), 69.85% (for 125 kg batch) and 66.20% (for 150 kg batch). The drying cost of paddy (Tk./kg) was found 0.71, 0.56 and 0.47 for three treatments respectively. • The performance of the vertical vacuum dehumidifying rice seed dryer was assessed in terms of drying rate, drying capacity, drying efficiency, and drying cost. • The temperatures of different points in the drying chamber were obtained in the range of 44.2–57.0 °C. • The paddy moisture content was reduced to the final moisture content of 10.6–12.0%. • The Vertical Vacuum Dehumidifying dryer meets the requirements of Bangladesh's small-scale farmers in terms of drying efficiency, drying capacity, and drying cost.

Farmers’ Rice Yield in Fallow - T. Aman Rice - Fallow Cropping Pattern Due to Variability in Genotype And Management

Farmers’ existing rice production practices provide key indications of interventions for improving yield in their environments. This study aimed to explore those indications in the Fallow - T. Aman rice - Fallow cropping pattern (CP) under rainfed farming practiced by the farmers in Kapasia, Gazipur. Research method employed one-to-one and face-to face interview of 154 farmers practicing the CP. The average yield of T. Aman was estimated as 3.23 t ha-1, slightly below the national average yield of 3.93 t ha-1, in the range of 1.18 to 5.65 t ha-1. Variety was one of the two broad factors that determined the yield variation. The high yeld potential (HYP) category absolutely preferred the production aim, where Swarna-Ranjit (31.2% by farmer) and BRRI dhan49 (24.7% by farmer) were the dominated varieties where average yields were very close (3.51 and 3.36 t ha-1) for Swarna-Ranjit and BRRI dhan49, respectively). Management was the second factor determining the yield variation within varieties. While both the varieties received similar maximum yield (5.65 t ha-1), Swarna-Ranjit produced the minimum yield of 1.40 t ha-1 and BRRI dhan49 of 1.98 t ha-1. This study did not find a consistent pattern of response of the three measured management components - transplanting time, seedling age and seedling density to yield in either variety. The yield variance of BRRI dhan49 under three management components was higher compared to Swarna-Ranjit. Farmers practiced relatively a wide range of three management combinations to achieve high yield in Swarna-Ranjit, but a narrow range of the three management combinations for BRRI dhan49 to achieve the same level of yield. It is concluded that the variety-specific agronomic management to be the avenue for yield improvements in farmers’ fields. Bangladesh Agron. J. 2022, 25(1): 23-36

Response of Biochar on Growth and Yield of Aman Rice Under Salt Stress

A pot experiment was conducted in Sher-e-Bangla Agricultural University, Dhaka, Bangladesh during aman season, 2018 to assess the effect of biochar on rice (BRRI dhan62) under salt stress conditions. The factorial experiment was laid out in Randomized Complete Block Design (RCBD) with four replications. Three levels of salinity were used viz. Control (S0), 1600 ppm NaCl (S1), and 2800 ppm NaCl (S2) under factor A and four levels of biochar were applied viz. 0 t ha−1 (B0), 2 t ha−1 (B1), 4 t ha−1 (B2) and 6 t ha−1 (B3) under factor B. The salt materials were added on pot in two installments at 20 and 30 days after transplanting (DAT). Exposure to salinity decreased growth and yield of rice including plant height, tillers hill-1, effective tillers hill-1, grains panicle-1, 1000-grain weight, grain yield and straw yield. The magnitude of growth and yield reduction increased with increasing the salinity level. Exposure of 1600 ppm and 2800 ppm NaCl declined the grain yield of rice by 28 and 100%, respectively. Straw yield (18 and 100%, respectively) and other yield contributing parameters declined by these two levels of salinity in the same way. Application of different levels of biochar ameliorated saltinduced damages to a certain extent. Under 2800 ppm NaCl stress, application of biochar extended life duration of rice plant upto 80 DAT, whereas without biochar application rice plant died after 60 DAT. Upon exposure to 1600 ppm NaCl stress, application of 2, 4 and 6 t ha−1 of biochar increased grain yield by 37, 42 and 30%, respectively, compared with the respective salt treatments (without biochar). Biochar enhanced yield of rice under saline conditions by enhancing yield contributing attributes including effective tillers and 1000-grain weight and by reducing salt-induced damages. However, response of 4 t ha−1 of biochar was best among the biochar levels (2, 4 and 6 t ha−1 of biochar) under both saline and non-saline conditions. Bangladesh Agron. J. 2022, 25(1): 105-113

Improvement of Existing Cropping Pattern Through Short Duration Mustard Variety In The Chalanbeel Area

The experiment was conducted at Dobila, Tarash of Shirajgonj in chalanbeel during the Rabi seasons of 2018-2019 and 2019-2020 to improve the existing cropping pattern, increase cropping intensity, yields and economic return through incorporating of modern crop varieties and improved management practices. The treatments were i) Mustard (var. BARISarisha-14)-Boro-Fallow cropping pattern, ii) Mustard (var. BARI Sarisha-15)- Boro-Fallow cropping pattern, iii) Mustard (var. Tori-7)-Boro-Fallow cropping patternandiv) Fallow–Boro–Fallow (existing cropping pattern). Boro rice (var. BRRI dhan29) was used to improve cropping pattern. The results revealed that the mean crop duration of improved cropping pattern ranged 192-195 days by inclusion of mustard. Rice equivalent yield of improved cropping pattern was 9.51-10.04 t ha-1 year-1 which was 46% higher than that of existing pattern (5.37 t ha-1 year-1). Land use efficiency (53%) of improved cropping pattern were 9 and 47% higher, respectively than those of existing cropping pattern. Higher mean gross return (Tk. 2,80,860 ha-1), gross margin (Tk. 169680 ha-1) and BCR (2.53) were recorded in improved cropping pattern: Mustard (var. BARI Sarisha-14)- Boro – Fallow} due to inclusion of high yielding variety of mustard than existing cropping pattern (Gross return: Tk. 161010 ha-1 and Gross margin: Tk. 86183 ha- 1) in chalanbeel area. Therefore, farmers in chalanbeel region of Bangladesh could follow improved cropping pattern for higher crop productivity and profitability where lands remain fallow before transplanting of Boro rice.
 Bangladesh Agron. J. 2022, 25(1): 83-90

Morphological Characterization and Adaptive Trail of Two Prominent T. Aman Rice (Oryza sativa L.) Lines under Different Locations of Bangladesh

Two advanced lines: BR8693-8-4-2-1 and BR8693-17-6-2-2, along with BRRI dhan49 (S. Ck) and BRRI dhan33 (R. Ck) as checks were tested at farmers’ field in eight locations such as West Byde (BRRI Gazipur), Khulna (Dumuria), Habiganj (Sadar), Chapainawabganj (Gomostapur), Rangpur (Sadar), Feni (Dagonbhuyan), Chattagram (Hathazari) and Barishal (Sadar) during the season of Transplanting Aman 2018. The trial was replicated three times in each location. The unit plot size was 17.94 m2 (4.6m x 3.9m). Seeding emergence for eight locations varied from 11-17 July 2018. Seedling age varied from 25-30 days among the locations. Seedlings were transplanted at 20 cm x 15 cm spacing. NPKS and Zn fertilizers were applied at the rate of 0, 15, 50, 12 and 3.6 kg ha-1, respectively. All fertilizers except urea were applied as basal whereas, urea was applied in 3 equal splits at 10, 25 and 40 days after transplanting (DAT) Other standard management practices were followed as and when necessary. No insecticide was used because the two advanced lines were insect resistant and diseases were not controlled (to identify susceptibility and tolerance level of lines). Date of seeding, transplanting, flowering and maturity, lodging tolerance, pest and disease incidence, phenotypic acceptance at vegetative and ripening stage, yield and yield components were recorded. Among the two advanced lines, BR8693-8-4-2-1 line was statistically significant from BR8693-17-6-2-2, BRRI Dhan49 and BRRI Dhan33 respectively and the disease reaction, farmers’ opinion, and special character of insect resistant, BR8693-8-4-2-1 was found to be superior for further variety trial. The main purpose of the experiment is to recommended insect resistant rice genotype for proposed variety trail. For yield estimation, 9 m2 sample area from each plot was harvested at maturity and grain yields were adjusted to 14% moisture content.

Methods of Urea Fertilizer Application Influence Growth, Yield, and Nitrogen Use Efficiency of Transplanted Aman Rice

Although urea placed deep reduces nitrogen (N) loss and increases rice yield, its use is not expanding due to the lack of effective application methods. A study was carried out to determine how different urea application techniques affected the yield and nitrogen use efficiency (NUE) of transplanted Aman rice (cv. BRRI dhan46). The experiment was set up in a RCBD design with seven treatments: T1 (deep placement of urea briquettes (DPUB) by hand), T2 (DPUB by battery-powered applicator), T3 (deep placement of prilled urea (PU) briquettes by BRRI applicator), T4 (DPUB by injector applicator), T5 (DPUB by push-type applicator), T6 (broadcast application of PU), T7 (zero-N), and three replications. Findings showed that the NH4+-N concentration in field water peaked on day 3 and then rapidly fell as time passed, while the NO3−-N concentration in the water and soil was minimal. T1 reported the highest grain yield, total N content and uptake, whereas T7 had the lowest values. On T1, the apparent N recovery reached its highest level (73.5%). The NUE varied from 13.26% in T3 to 29.38% in T1. Based on this finding, deep placement of urea briquette by hand is recommended for increasing the yield and NUE of T. Aman rice.

Estimation of Genetic Variability, Heritability and Genetic Advances for Short Duration and High Yielding Rice Genotypes

The goal of the study was to find genotypes of 18 different rice varieties that would yield a lot of rice in a short amount of time. With this in mind, the study genotypes' field performance as well as the relationships between various morpho-physiological and yield-contributing traits among the genotypes was assessed. The experiments were conducted from July to December 2018 at the Agronomy Field, Department of Agronomy and Agricultural Extension, Faculty of Agriculture, Rajshahi University. In genotype BRRI dhan 51, the maximum number of days to 50% flowering was discovered. The genotype BRRI dhan 56 had the lowest number of days required for 50% flowering. Genotypes showed a wide range of days to maturity (92.00–109.00), with an average of 98.96 days. The genotypes DRR 46, BINA 7, and DRR 44 are followed by the genotypes BRR1 dhan 66, BRR1 dhan 56, and BRR1 dhan 57, which have shorter maturity periods (i.e., 92.00 days), indicating earliness. The traits investigated in this study showed high heritabilities, with estimates ranging from 67.00 to 96.00 percent. Days to flowering and unfilled grain panicle-1 had the highest heritability among the traits (96.00%).The presence of high heritability values suggests that the expression of the traits under study is less influenced by the external environment. The unfilled grain panicle-1 had the highest genetic advance as a percentage of the mean (144.80%), while panicle length had the lowest genetic advance (10.48%) among the traits that affected yield.

Effects of Herbicidal Weed Control Practices on Yield Performance of T. Aman Rice Varieties in Bangladesh

Using a weed control scheme could assist in reducing potential production losses caused by weeds in paddy fields. Due to certain undesirable adverse effects, there is currently no realistic alternative to chemical weed suppression approaches in rice. The present research aimed to assess how various herbicide-based weed control techniques influenced the weed profile, and crop production of T. aman rice varieties. The study was done employing a randomized complete block design with 3 trials. The investigation comprised three aman rice cultivars and four weeds control techniques such as control, pre-emergence herbicide, early post emergence and post emergence herbicide. On research sites, ten weed types from 5 families were revealed. The grass weed Echinochloa gras-galli had the highest summed dominance ratio (SDR: 42.05%), while the sedges Scirpus mucronatus had the lowest SDR of 0.81%. Post-emergence herbicide application provided the lowest weed biomass and density at all sampling dates and produced the greatest seed yields (4.25 t ha-1), straw yield (5.41 t ha-1) and harvest index (43.87%) because of minimal crop-weed competition. In the case of interaction, BRRI dhan49 coupled with post emergence herbicide attained maximum output (4.80 t ha-1) followed by BRRI dhan49 with early post emergence. Due to ability for reducing weeds population, usage of post emergence herbicide could be considered as an efficient weed control approach in BRRI dhan49.

Crop coefficient, reference crop evapotranspiration and water demand of dry‐season Boro rice as affected by climate variability: A case study from northeast Bangladesh

AbstractClimate variability and change significantly influence crop water demand by affecting crop coefficient (Kc), reference crop evapotranspiration (ETo, a grass reference) and potential crop evapotranspiration (ETc). The climatic effects on these hydroclimatic parameters were investigated in the past mostly for the entire crop growth period, but little or no information is available on their variation over different growth stages of the crops, specifically in Bangladesh. Therefore, this study intended to evaluate the climatic effects on these hydroclimatic parameters at the initial, development, mid‐season and late‐season growth stages of two rice varieties (Bangladesh Rice Research Institute [BRRI] dhan28 and BRRI dhan29) dominantly grown in the dry season in two northeast districts/subdistricts (Sylhet and Srimongal) as well as many other districts of Bangladesh. Kc, ET0 and ETc were analysed for the period from 1994 to 2015 using the analytical approach of the Food and Agriculture Organization (FAO) Penman–Monteith method. The results revealed that the Kc of the rice varieties increased in all growth stages over time, with the maximum Kc (1.247) in the mid‐season stage in Srimongal. ETo and ETc were found to be maximum in the mid‐season and late‐season stages, respectively. The potential crop water demand (CWRpot) greatly varied among the initial and development stages and between the two rice varieties. The initial and mid‐season growth stages of rice required more water than the other growth stages. The results on the growth stage‐wise variation of the hydroclimatic parameters pertinent to rice cultivation may greatly contribute to irrigation scheduling for dry‐season rice cultivation and planning water resources in the study region.

EFFECT OF POULTRY MANURE AND FARMYARD MANURE WITH AND WITHOUT CHEMICAL FERTILIZERS ON THE GROWTH AND YIELD OF BRRI DHAN28

A field experiment was conducted at the Agrotechnology Field Laboratory of Khulna University, Khulna during boro season of 2005 to find out the effects of poultry manure (PM) and farmyard manure (FYM) in presence and absence of chemical fertilizers on BRRI dhan28. The experiment was laid-out in a randomized complete block design with three replications. There were ten treatments viz. T1: 100% RFD (Recommended fertilizer doses), T2: 100% RFD+10 t FYM, T3: 100% RFD+ 5 t FYM, T4: 50% RFD+5 t FYM, T5: 10 t FYM, T6: 100% RFD + 5 t PM, T7: 100% RFD+ 2.5 t PM, T8: 50% RFD+ 2.5 t PM, T9: 5 t PM and T10: Control (without manures and fertilizers). The doses of inorganic fertilizers N, P, K, S and Zn were 80, 50, 40, 10 and 5 kg ha-1. All the combined application of manures and fertilizers significantly increased the plant height, number of tiller hill-1, dry matter hill-1, grain and straw yield over the control. The highest grain yield was recorded in 100% RFD + 5 t PM treated plot which was similar to 100% RFD+10 t FYM treated plot, while the lowest yield was recorded in the control. Half of the recommended doses of fertilizer with 5 t ha-1 farmyard manure or 2.5 t ha-1 poultry manure produced statistically similar grain yields as produced by RFD which indicates that 50% of the fertilizers can be replaced by PM or FYM without any loss of grain yield.

PERFORMANCE OF HIGH YIELDING RICE VARIETIES OF BANGLADESH

The performance of BRRI dhan28, BRRI dhan47, BRRI dhan50 and one exotic rice variety Koshihikari (Japanese) was observed in boro season from November, 2011 to May, 2012. The varieties were evaluated on growth, yield and yield contributing characteristics of rice. In the early stages of growth viz. 60 DAS, 70 DAS and 90 DAS Koshihikari variety had the maximum plant height. BRRI dhan47 was the tallest (93.20 cm) and Koshihikari was the shortest plant (78.32 cm) at the time of harvest. In the early stage (60 DAS) the tiller number hill-1 was maximum for the BRRI dhan28 (12.48) and in the time of harvesting Koshihikari had the maximum tiller number hill-1(16.08). Koshihikari was the earliest variety compare to the other varieties because it took the minimum time for booting (73.8 DAS), flowering (85.8 DAS), grain maturity (113.2 DAS) and harvesting (124 DAS). The effective tiller number per hill-1 was significantly higher for the Koshihikari variety (16.08) from the other three high yielding varieties of Bangladesh. The longest panicle length had been observed in BRRI dhan47 (22.62 cm) and shortest was found in Koshihikari (14.91 cm). The number of spikelet and grain panicle-1 was highest for the BRRI dhan50 (136.12 and 119.34 respectively) and minimum for Koshihikari (66.42 and 59.57 respectively). BRRI dhan47 had the maximum 1000-grain weight (22.23 g) and BRRI dhan50 had the minimum (17.32 g). The maximum yield was found in BRRI dhan47 (7.61 t ha-1) and the lowest yield was observed in Koshihikari (5.60 t ha-1). The straw yield and biological yield was highest for the BRRI dhan50 and lowest for Koshihikari. The harvest index was found maximum in Koshihikari (59.67 %) and minimum in BRRI dhan50 (52.57 %).