BARI Gom Research Articles

Lead tolerance is related to its root exclusion through the regulation of Fe uptake genes (TaNAAT1 and TaDMAS1) in hexaploid wheat

Lead (Pb) is toxic to plants. In this study, the differential tolerance to Pb in contrasting wheat (Triticum aestivum) genotype was studied cultivated under control and Pb-toxic (300 μM Pb) hydroponic conditions. Pb-toxicity caused retardation in morphological characteristics, membrane stability, cell viability and redox state in Bari Gom-26 (Pb-sensitive), but not in Akbar (Pb-tolerant), indicating that Akbar can combat Pb toxicity. Pb accumulation in root and shoot of was 5-fold lower in Akbar than that of Bari Gom-26, implying that restricting Pb uptake in roots may be linked to Pb tolerance. Also, we observed a significant increase of Fe in Bari Gom-26 accompanied by upregulation of TaNAAT1 (nicotianamine aminotransferase) and TaDMAS1 (deoxymugineic acid synthase), whereas Akbar showed steady Fe status and downregulation of TaNAAT1 in roots of genome A. This is correlated with the steady chlorophyll score and Fv/Fm (maximum quantum yield of PSII) in leaves of Akbar while these were severed affected in Bari Gom-26 that may be linked to Pb-induced oxidative damage. In interactome analysis, YS1 gene network (Fe-PS transporter) was found to interact with TaDMAS1. Genome A and B of TaNAAT1 were located in chloroplast while D was in mitochondria; however, A, B and D of TaDMAS1 were localized in the cytoplasm. Additionally, we observed no changes in citrate and malate in the roots of Akbar, implying the ability of this genotype to regulate Fe-chelation under Pb stress. These suggest that genetic variation in Pb-toxicity tolerance in wheat is primarily root-based and that the Pb limitation is primarily driven by strictly limiting Fe-uptake and chelation in roots. These findings may encourage breeding or transgenic strategies to develop Pb-tolerant wheat.

Changes in Photosynthetic Pigment of Wheat(Triticum Aestivum L. Var. Bari Gom-25) As Affected By Naa and N-Fertilizer

A field experiment was conducted to investigate the changes inphotosynthetic pigment of BARI Gom-25 as affected by foliar spray of NAA andN-fertilizers. The experiment consisted of seven different concentrations of NAA(NAA0 = 0, NAA1 = 10, NAA2 = 20, NAA3 = 30, NAA4 = 40, NAA5 = 50 and NAA6 =60 ppm) and five N-levels (F0=0, F1=25, F2=50, F3=75 and F4=100% of therecommended dose) and their 35 combination treatments. Results revealed thatfoliar application of 40 ppm NAA (NAA4) produced higher chlorophyll a contentat all stages (tillering, flowering and grain filling) and were significantly higherthan control at tilling and flowering stages. Chlorophyll b and carotenoidcontents did not show any general trend to NAA at any stage except at tillingstage. Application of 50% of the recommended N-fertilizer (F2) producedsignificantly maximum photosynthetic pigment contents at tilling stage whereas,at flowering stage the same results were obtained from 100% of therecommended N-fertilizers (F4) but with few exceptions. At grain filling stage,photosynthetic pigment did not show any general trend to N-fertilizerapplication. Findings on combined effects indicated that 20 and 30 ppm NAA incombination with 50% N-fertilizer (NAA2F2 and NAA3F2) had producedsignificantly maximum chlorophyll a content at tilling stage. However, atflowering stage the highest chlorophyll a content was noted from NAA2F4treatment (20 ppm NAA in combination with 100% N-fertilizer). Findings alsorevealed that combined application of NAA and N-fertilizer had not resulted anygeneral trend on chlorophyll b and carotenoid contents in most of the caseswhere the maximum value in photosynthetic pigment was found depending onthe concentrations of NAA, fertilizer dose and plant growth stages. Dhaka Univ. J. Biol. Sci. 31(1): 169-176, 2022 (January)

Soil supplementation with Si, B and Zn and their synergetic effects in reducing severity of wheat blast (Magnaporthe oryzae Triticum)

Wheat blast (Magnaporthe oryzae Triticum) in Bangladesh and South America is recognized as one major limiting factor of wheat production. Its control using chemical pesticides raises concerns about food safety and pesticide resistance, which have dictated the need for alternative blast management approach, nutrient supplementation could be an ecofriendly alternative. Experiments were carried out under confined net house condition for two consecutive cropping seasons. Single doses of the nutrients (Si, B and Zn) were incorporated during soil preparation. Plants of the wheat blast susceptible variety BARI Gom-26 were inoculated with spores (1 x 107 spores ml-1) of Magnaporthe oryzae Triticum at blast vulnerable pre-heading stage of 52 days age. Typical wheat blast symptoms of spike bleaching from top to downward appeared on sight 14 days after inoculation i.e., 66 days age of the crop. Incidence and severity of blast bleaching of spike were scored for four times starting from 68 days age @ three day’s interval. None of the nutrients could stop the incidence of blast on wheat; however, some nutrients reduced the blast incidence significantly. Solo application of Si, B and Zn or combination of two caused significant reduction of spike bleaching. With the mixed application of Si, B and Zn, > 47% reduction of wheat blast severity was obtained. The results revealed that the soil application of silicon, zinc and boron had a synergistic effect on the intensity of blast disease of wheat. Int. J. Agril. Res. Innov. Tech. 11(2): 76-84, Dec 2021

Evaluation Of Germination Quality Of Wheat Seeds Dried In Fluidized Bed Dryer

An attempt was conducted taking three wheat varieties (BARI gom-24, Shatabdi, Bijoy) to investigate the application and suitability of single-stage fluidized bed drying for quality wheat seeds in terms of germination percentage. Drying of wheat seed was conducted in a fluidized bed dryer at three temperatures of 35°C, 40°C, and 45°C at a constant bed thickness of 13 cm and 4.5 m/s of air velocity. Total drying time required for drying of each variety 210 min (3.5hr), 150 min (2.5hr) and 80 min (1.3hr) at temperature 35°C, 40°C, and 45°C respectively for reduction of moisture from 16.98±0.15% to 12±0.1% wb. In contrast, sun drying (33±2°C) took 270 min (4.5 hr). It was shown, the drying time required in the fluidized bed drying method was almost 22-71% shorter than the sun drying method. The germination percentage was 94.67%, 97.33%, 88% for the variety “BARI gom-24” 93.67%, 97%, and 91.33% for the variety Shatabdi and 95%, 96.67%, 89.67% for the variety Bijoy while dried in a fluidized bed dryer at temperature 35°C, 40°C, and 45°C respectively. The germination percentage of sun-dried samples was 90.67% (BARI gom-24), 92.33%. (Shatabdi) and 92% (Bijoy). In the comparison of germination, wheat seed samples dried in the fluidized bed dryer at 35°C, 40°C showed a higher germination percentage than sun drying wheat seed samples. Therefore, the proposed drying technique does not only facilitate faster removal of moisture content, and also a higher germination percentage was found than the existing sun drying method. So, fluidized bed drying can be effective for wheat seeds in Bangladesh.

Influence of irrigation regimes and mycorrhizal inoculation on the performance of wheat in pot culture

In order to find out the effect of arbuscular mycorrhizal fungi (AMF) and level of irrigation on wheat, an experiment was conducted in the net house of Department of Agronomy, Bangladesh Agricultural University during November 2018 to April 2019. The study included two levels of AMF inoculation (inoculated and non-inoculated) and three levels of irrigation (viz., no irrigation, one irrigation during CRI stage, and two irrigations at tillering and flowering stages respectively). The treatment combinations were applied to two wheat varieties, viz., BARI Gom-25 and BARI Gom-30. The pot experiment was laid out in randomized complete block design (RCBD) with three replications. Commercially available mycorrhizal inoculum (Gigaspora margarita) was used to inoculate the plants of respective treatment pots. The performances of these wheat varieties under two AMF inoculation levels (inoculated and non-inoculated) showed that both varieties were significantly affected by AMF inoculation. Though all growth and yield contributing parameters were not significantly affected by AMF application, it was evident that AMF inoculation helped the wheat plants to grow vigorously and produce higher yield. Both wheat varieties showed their best performance under two irrigation treatment but when inoculation was imposed, it gave better performance than non-inoculated pot. The highest yield was recorded with pots which were inoculated with AMF in both wheat varieties. It was observed that in both varieties, irrigation helps wheat to perform better in terms of all parameters in comparison to no irrigation condition, and two irrigations gave better results than that of one irrigation. AMF inoculation gave higher yield in non-irrigated pots in comparison to non-inoculated non-irrigated pots. Inoculation with AMF increased 25\\% grain yield plant-1 compared to the non-inoculated pots. The results suggest that farmers could be advised to grow wheat in drought prone areas using AMF.

Effects of soil amendments using potassium in elevating resistance against wheat blast disease

Potassium (K) is unique among the essential nutrient elements for its diversified role in plant metabolic processes. Potassium improves crop output, protects the crop from diseases and insect-pest infestation, prevents lodging, and reduces the effects of terminal heat stress. Based on this information, it was hypothesized that K will enhance host plant resistance and blast control while increasing yields. A pot experiment was conducted by artificially inoculating Magnaporthe oryzae Triticum (MoT) on a susceptible wheat (Triticum aestivum L.) variety (BARI Gom-26) to determine the effect of soil application of K on blast disease management and the growth and yield. The experiment was carried out in separate plastic pots containing 18kg of virgin soil at the net house of the farm of the Bangladesh Institute of Nuclear Agriculture headquarters, Mymensingh, for two growing seasons of 2018-19 and 2019-20 following a completely randomized design with five treatments and three replications. The dose for soil application were 0, 50, 75, 100 and 125 K kg ha-1, respectively. Disease incidence (%) and severity (%) of wheat blast were evaluated at 11, 13 and 15 days after inoculation (DAI). At 15 DAI, the highest disease incidence (95.45%) was found in absolute control followed by K0 (0 kg K ha−1) (91.98%) and the lowest blast incidence (64.49%) was found in K4 (125kg K ha−1) which was statistically similar with K3 (100kg K ha−1) (70.87%). At 15 DAI, the highest blast severity matrix (90%) was found in absolute control followed by K0 (0 kg K ha−1) (76.02%) and the lowest blast incidence (46.18%) was found in K4 (125kg K ha−1) which was significantly different with others. Among the treatments, 125 kg K ha-1 produced the highest grain yield (26.97 g pot-1) and the lowest (5.79 g pot-1) was found from the absolute control. Flag leaf samples were randomly collected before head emergence from each pot and analyzed in the laboratory for plant nutrient content. The K concentration of flag leaves sample ranged from 1.71% to 5.51% with the average concentration of 3.02%, where the highest K content (%) was recorded in K4 (5.51%) and the lowest was found in absolute control (1.71%). Potassium fertilization appeared to reduce the severity and improve yield of wheat. Correlations suggested that improving dry matter production and K uptakes at the boot stage by K fertilization can reduce severity later in the growing season and increase wheat grain yield. It can be concluded that high K concentration on leaf tissue was important to decrease wheat blast symptom.

Organic Amendments Improve Plant Morpho-Physiology and Antioxidant Metabolism in Mitigating Drought Stress in Bread Wheat (Triticum aestivum L.)

Due to the unpredictable climate change, drought stress is being considered as one of the major threats to crop production. Wheat (Triticum aestivum L. cv. BARI Gom-26) being a dry season crop frequently faces scarcity of water and results in a lower yield. Therefore, this experiment aims to explore the role of different organic amendments (OAs) in mitigating drought stress-induced damage. The pot experiment consisted of different organic amendments viz. compost, vermicompost and poultry manure @0.09 kg m−2 soil, biochar @2.5% w/w soil and chitosan @1% w/w soil which was imposed on the plants grown under both well-watered and drought conditions. Results showed that drought stress reduced plant height (15%), SPAD value (16%), relative water content (13%), number of spikelet spike−1 (17%), number of grains spike−1 (12%), and 100-grain weight (18%). Organic amendments act as a protectant and reduce drought stress-induced damages by enhancing the morpho-physiological and yield attributes. Vermicompost enhanced SPAD value by 18%, number of spikelets spike−1 by 20%, number of grains spike−1 by 17%, whereas poultry manure increased plant height by 16% under drought condition compared to control plant. Unlike other OAs applied, vermicompost was proved to be capable of reducing the higher lipid peroxidation and proline content raised by drought condition. Drought stress-induced increment of catalase, ascorbate peroxidase and glutathione reductase activities were also efficiently modulated by the organic amendment application. The present study concluded that OAs play significant roles in alleviating drought stressinduced damages by improving the morpho-physiological attributes and among the different types of OAs used vermicompost performed better which in addition ceased the production of reactive oxygen species.

Organic Amendments with Poultry Manure and Cow Dung Influence the Yield and Status of Nutrient Uptake in Wheat (<i>Triticum aestivum</i>)

The field experiment cultivating wheat during the winter season from November 2014 to March 2015 was conducted in the “North Eastern Barind Tract Soils” at Kushadaha, Nawabganj, Dinajpur in Bangladesh. The wheat variety BARI Gom 26 was selected in focusing to evaluate the effects of organic amendments using poultry manure (PM) and cow dung (CD) on the growth, yield and nutrient uptake by the plant. The texture of the field soil was clay with acidic nature (pH 5.61). The trials comprise three treatments following a randomized complete block design (RCBD) replicated thrice. Results showed that significantly greater plant height, number of tillers per hill and straw yield were 98.10 cm, 3.66 and 5425 kg/ha respectively in receiving the treatment T2 than T3 (95.66 cm, 3.38 and 4483 kg/ha) and T1 (control). Spike length, 1000 grain weight and grain yield were 9.23 cm, 39.81 kg/ha and 3100 kg/ha respectively also higher in T2 treatment than T3 (8.76 cm, 38.51 kg/ha, 3091 kg/ha) with no statistical differences among them. Therefore, the treatment T2 (PM) comprised of poultry manure and NPK exhibited as the best treatment for producing the highest in all growth and yield parameters of wheat. In wheat grain, the content of N, P, K, S, Mg, Zn and B ranged from 1.080% to 1.380% N, 0.390% to 0.398% P, 0.780% to 0.840% K, 0.079% to 0.111% S, 0.181% to 0.187% Mg, 25.56 to 29.77 ppm Zn and 10.12 to 12.54 ppm B. Similarly in straw, nutrients content ranged from 0.220 to 0.300% N, 0.045% to 0.074% P, 0.970% to 1.250% K, 0.152% to 0.191% S, 0.097% to 0.101% Mg, 10.78 to 13.23 ppm Zn and 27.98 to 2989 ppm B. Therefore, organic amendment with 5-ton cow dung (CD) ha-1 with a recommended dose of NPK significantly increased the content of N, S, Mg, Zn and B in the grain and straw of wheat. Alternatively, the poultry manure treatment with NPK significantly increased the content of P and K in the grain and straw of wheat. However, results revealed that the treatments T2 and T3 comprising a recommended dose of NPK with poultry manure and cow dung respectively could increase the content of N, P, K, S, Mg, Zn and B in wheat. The overall results expressed that the poultry manure treatment with NPK (T2) exposed as superior for producing the top growth and yield attributes of wheat in the studied area.

Yield Performance of Heat Tolerant & Early Maturing Wheat Varieties in Chattogram Region

The experiment was conducted in two consecutive crop seasons (2015-16 and 2016-17) at Regional Agricultural Research Station (RARS), Hathazari, Chattogram during Rabi season (November to March) with 3 duplicate laid out Randomized Complete Block Design (RCBD) to compare the rehearsal of high-placed outcome, early maturing and heat tolerant varieties under increasing temperature. BARI released early maturing wheat varieties were used for optimum sowing time and heat tolerance as an adaptive mechanism suffering from terminal heat stress. Six heat-tolerant early maturing wheat varieties were (BARI Gom 25, BARI Gom 26, BARI Gom 27, BARI Gom 28, BARI Gom 29, and BARI Gom 30). The highest crop output was gained from BARI Gom 30 (4.33 t/ha) followed by BARI Gom 26 (4.06 t/ha) in a couple of years. The lowest yield was found from BARI Gom 27 (2.66t/ha) followed by BARI Gom 29 (3.53 t/ha), BARI Gom 28 (3.36 t/ha), and BARI Gom 25 (3.13 t/ha) both years. Crop output of wheat and amount of spike showed significant difference and rest of the parameters were insignificant. The earliest maturing variety was BARI Gom 30 and produced a maximum crop yield than others. BARI Gom 30 showed a maximum benefit-cost ratio (BCR) of 1.73 and BARI Gom 27exhibited the lowest benefit-cost ratio (BCR) of 1.06. This result of the experiment showed that early high yielding variety and the best adaptive variety was BARI Gom 30 among the six varieties in Chattogram.

Effect of Late Seeding Warmer Condition on Phenology and Yield of Wheat

Four wheat variety/genotype (BARI Gom-26, BAW-1202, BAW-1182 and BARI Gom-27) were tested under three heat stress regimes (normal, moderate and severe) to evaluate the effect of late seeding warmer condition on phenology and yield of wheat, as well as to identify suitable cultivars to develop heat-tolerant genotypes at Hajee Mohammad Danesh Science and Technology University (HSTU), Dinajpur during November, 2016 to April, 2017. Results revealed that genotype BAW-1182 and BAW-1202 showed greater thermostability of cell membrane with acceptable yield performance under heat stress condition. The order of tolerance based on heat susceptibility index (based on grain yield) was BAW-1182>BAW-1202>BARI Gom-27>BARI Gom-26 under heat stress conditions. Thus, BAW-1182 and BAW-1202 have the greatest potential to be used as high-yielding wheat genotypes under warm to hot environments and could be used in a breeding programme to develop heat-tolerant wheat.
 Bangladesh Agron. J. 2021, 24(1): 13-23

Inluence of Different Levels of Cowdung on Mitigation of Water Deficit Effect on Wheat

The experiment was conducted in pot at the net house of the department of Agronomy, Sher-e-Bangla Agricultural University, Dhaka during the period from November, 2018 to March, 2019to find out the optimum dose(s) cowdung to mitigate the water deficit effect on wheat. The experiment comprised of two factors viz. factor A: Five levels of cowdung, i) C0= Control (No cowdung), C1= 25% less cowdung of recommended dose, C2 = Recommended dose of cowdung, C3 = 25% higher cowdung of recommended dose and C4 = 50% higher cowdung of recommended dose, and factor B: four levels of water deficit at, i) D0 = Control (No water deficit), D1= Crown root initiation stage (20-19 DAS), D2 = Booting stage (45-54 DAS) and D3= An thesis stage (55-64 DAS). The experiment was laid out in a Factorial R and omized Complete Block Design with three replications. The test crop variety was BARI Gom28. The result reveled that cowdung level had positive impact on yield of wheat under water deficit condition, and 50% higher cowdung of recommended dose (C4) gave the highest grain yield (5.12g plant-1). The particular treatment also produced the highest number of effective tillers plant-1 (5.25), spike length (10.39 cm), spikelet spike-1 (15.72), grains spike-1 (32.56), grains spikelet-1 (2.07) and 1000-grain weight (47.32 g) of wheat. The treatment C3 (25% higher cowdung of recommended dose) also gave statistically similar yield with C4 treatment. In respect of water deficit imposition treatments, grain yield was found the highest in control treatment which was statistically similar with water deficit imposition at booting stage treatment (D2). These two treatments also showed the higher and similar number of effective tillers plant-1 (4.86 and 4.58), spike length (10.53cm and 10.11cm), spikelets spike-1(15.50 and 15.19), grains spike-1 (34.10 and 30.17), grains spikelet-1 (2.20 and 1.98) and 1000-grain weight (45.42g and 45.36g, respectively). Regarding the interaction of levels of cowdung and water deficit imposition at different stages of plant growth, C4D0 and C3D0 were highest yielder which was attributed to higher 1000-seed weight, number of effective tillers plant-1, spikelets spike-1 and grains spike-1. Contrary, 25% higher cowdung than recommended dose (as it saved 25% cowdung) seems promising to overcome yield loss due to water deficit imposition at booting stage of wheat (D2). However, application of cowdung (12.5 t ha-1) was found effective to combat water deficit at booting stage (D2) of wheat compared to other growth stages. Bangladesh Agron. J. 2021, 24(1): 93-100

Evaluation of Drought Tolerance of Some Wheat (Triticum aestivum L.) Genotypes through Phenology, Growth, and Physiological Indices

Increasing human population and changing climate, which have given rise to frequent drought spells, pose a serious threat to global food security, while identification of high yielding drought tolerant genotypes remains a proficient approach to cope with these challenges. To offer a methodology for the evaluation of the drought-tolerant wheat genotypes based on the pheno-physiological traits, a field experiment was executed, entailing four wheat genotypes viz. BARI Gom 26, BAW 1158, BAW 1167, and BAW 1169 and two water conditions viz. control treatment (three times irrigation at 20, 50, and 70 DAS, i.e., 100% field capacity) and stressed treatment (no irrigation during the entire growing season). The results revealed that drought stress drastically reduced the days to booting, heading, anthesis and physiological maturity, relative water content (RWC), chlorophyll content, canopy temperature depression (CTD), and photo-assimilates-spike dry matter (SDM), grains spike−1 and grain yield of all wheat genotypes. In addition, the genotypes BAW 1167 and BARI Gom 26 remained more prone to adverse effects of drought as compared to BAW 1169 and BAW 1158. Furthermore, DS induced biosynthesis of compatible solutes such as proline, especially in BAW 1169, which enabled plants to defend against oxidative stress. It was inferred that BAW 1169 remained superior by exhibiting the best adaptation as indicated by the maximum relative values of RWC, total chlorophyll, CTD, proline content, SDM, grains spike−1, and grain yield of wheat. Thus, based on our findings, BAW 1169 may be recommended for general adoption and utilization in future wheat breeding programs aimed at developing potent drought-tolerant wheat genotypes to ensure food security on a sustainable basis.

Growth and Yield of Wheat as Influenced by Micronutrients Under Water Deficit Condition

Crop productivity is greatly affected by drought stress. In order to evaluate the effects of Zn and Fe micronutrients on growth and yield of wheat (Triticum aestivum L.) variety BARI Gom 29, a pot experiment was conducted at the Agronomy research field of Bangabandhu Sheikh Mujibur Rahman Agricultural University during November 2018 to March 2019. Two water regimes i.e. control (80% of field capacity) and drought (40% of field capacity) were maintained throughout the growing season. Micronutrients Zn and Fe viz. i) ZnSO4.7H2O and Fe3SO4.7H2O @22 kgha-1were applied in soil before sowing; ii) ZnSO4.7H2O solution and Fe3SO4.7H2O solution @ 5% of each were applied as foliar spray at flowering stage following completely randomized design (CRD) with three replications. The results indicated that drought stress affected negatively wheat growth such as plant height, fresh weight of leaf, stem, root and total weight of plant as well as yield. Zn and Fe mitigate the drought effects in wheat which ultimately improve the growth and the yield. Among the micronutrients, Fe (Fe3SO4.7H2O) was found more effective when it was applied as foliar spray @ 5% solution for increasing the growth and yield of wheat under water deficit stress condition. Bangladesh Agron. J. 2021, 24(1): 119-128

Effects of Osmotic, Thermal and Plant Growth Regulators Seed Priming on Different Wheat Varieties

Proper germination and proper growth of seedlings in conventional farming methods are often not achieved at the desired rate. The purpose of priming is to reduce germination time and improve stand and percentage of germination and increases vigour for fast and strong plant development. In order to evaluate the effect of seed priming on growth and yield of wheat the present study was conducted at Agronomy Farm House, Rajshahi University. Three wheat varieties (BARI Gom-24, BARI Gom-25 and BARI Gom-26) were tested with three groups of priming media (osmo-priming, thermos-priming and plant growth regulator priming) and control (non-soaked). Seeds were primed for 24 h at 25°C with four priming media, osmo-priming (1% NaCl, 2% KNO3, 2% KH2PO4, and 10% PEG), PEG-Priming (50 μM GA3 and 50 μM BAP) and thermo-priming (0°C, 5°C and 10°C) and control was without priming agent. All types of priming media were significantly different among their types for plant height (cm), tiller number and dry biomass (g). PEG was significantly different in osmo-priming, GA3 was significantly different in PGR-priming and 0°C was significantly different in thermo-priming. In case of vigor index, 2% KH2PO4 was suitable among osmo-priming, GA3 was better than BAP priming and 0°C was optimum among all temperature priming. Seed priming helps seeds to grow rapidly and evenly in the field, producing healthier and faster maturing crops with better yields. J. Bio-Sci. 29(2): 111-122, 2021 (December)

Assessment of wheat variety adoption in Bangladesh through DNA fingerprinting

AbstractWheat (Triticum aestivum L.) demand in Bangladesh has increased significantly in recent years, becoming the second major staple cereal after rice (Oryza sativa L.). Domestic production of wheat accounts for only 16% of domestic use. More than 30 wheat varieties have been released in the past 30 yr by the Bangladesh Wheat and Maize Research Institute (BWMRI). In the last 10 yr alone, nine varieties with improved yield and disease resistance have been released. Bangladesh and the BWMRI lack the regulatory framework and infrastructure to accurately track the rate of adoption of these new releases. To determine the adoption of these varieties across the country, DNA fingerprinting of wheat samples was conducted across the six wheat growing regions in Bangladesh during the 2018–2019 cropping season. A reference library was established to compare and identify the wheat samples collected from farmers’ fields. Wheat grain samples collected from the fields and breeders’ lines were genotyped using Diversity Arrays Technology sequencing (DArTseq)‐based single nucleotide polymorphism (SNP) markers. Of the 1,791 samples collected from farmers’ fields, 68% were identified as varieties released after 2000 and 32% matched with older varieties. Among the varieties grown, BARI Gom 25 represented 29% of the collected samples followed by 23% of BARI Gom 24 and 16% of BARI Gom 26. These three most common varieties were well distributed across the six regions and have broad adoption.

Evaluation of Critical Limit of Sulphur in Soils for Wheat (Triticum aestivum L.) and Mustard (Brassica napus L.)

The conception of critical limit (CL) of a nutrient element distinguishes its deficiency from sufficiency, which could advise fertilizer application. A pot culture experiment was conducted during Rabi season (2019–2020) to study the CL of sulphur (S) in soil and plant. A total of 20 soil samples collected from intensive cropping areas of three agroecological zones (AEZs) of Bangladesh were used in the experiment. The 0.15% CaCl2 extractable S (expressed as available S) contents of the test soils ranged from 6.84 mg/kg to 38 mg/kg. Wheat (Triticum aestivum L.) cv. BARI gom 30 and mustard (Brassica napus L.) cv. BINA sorisha 9 were used as test crops in this study. There were two rates of S application to soil-0 and 15 mg/kg for wheat and 0 and 18 mg/kg for mustard from gypsum (CaSO4.2H2O). Each S treatment was replicated thrice. Dry matter yield, S content and S uptake by the crops increased with added S. For mustard, the CL of soil S was estimated to be 14 mg/kg by graphical procedure and 11 mg/kg in statistical method while plant tissue concentration showed the CL of 0.35% in both methods. The CL of soil S for wheat was found to be 14 mg/kg and 11 mg/kg in graphical and statistical methods, respectively, and the CL of plant tissue concentration was recorded as 0.14%, in both methods. It is expected that mustard and wheat crops would respond to S fertilization in soils containing S at or below the CL. The results would be useful for predicting crop (wheat and mustard) response to S fertilizer and developing efficient S fertilizer management to promote sustainable crop production.

Optimizing the Seed Rate for Maximized Yield And Benefits of Wheat Under Strip Tillage In Bangladesh

An on-farm experiment was conducted at the farmer's field located at the Durbachara village of Gauriopur upazilla under the Mymensingh district of Bangladesh from November 2015 to March 2016 to study the effect of seed rate on yield performance of wheat under strip tillage. Wheat cv. BARI Gom-26 was sown under conventional tillage (CT) vs. strip tillage (ST), including four seeding rates viz. 100, 110, 120, and 130 kg ha-1. The CT was done with a two-wheel tractor and consisted of two primary tillages followed by two secondary tillages. The ST was done using a Versatile Multi-crop Planter (VMP) machine in a single pass process. A pre-plant herbicide, glyphosate was applied 3 days before of ST operation @ 3.7 L ha-1. The experiment was laid out in a randomized complete block design with four replications. The impact of tillage methods on the seed rate was found significant in the yield and economic profit of wheat. The longest spike with the highest number of grains spike-1, the highest weight of 1000-grain, grain yield, and BCR was recorded when 120 kg seeds of wheat sown with strip tillage. This practice produced a 25% higher yield and earned 51% higher profit than the practice of seeding 100 kg seeds ha-1 with conventional tillage. SAARC J. Agric., 19(1): 45-56 (2021)

Determining an effective and economic fungicide spray schedule for reducing blast of wheat

Wheat blast, caused by the fungus Magnaporthe oryzae pathotype Triticum (MoT), constitutes one of the major obstacles to the expansion of wheat production in Bangladesh. In the absence of resistant variety, fungicide control is the first-hand effort. Determining an effective and economic fungicide spray schedule in controlling blast disease of wheat was aimed. Ten fungicides were tested during two consecutive cropping seasons of 2018-2019 to 2019-2020. The wheat plants of blast susceptible cultivar BARI Gom 26 were inoculated with spores (107 spores ml-1) of MoT at pre-heading stage of wheat (52 days age). Fungicides were applied both before inoculation and after the appearance of blast symptoms in cocktail for three times starting from booting of wheat at 7 days interval. Plants received the combination of Filia (Tricyclazole 40% + Propiconazole 12.5%) and Seltima (Pyraclostrobin 10%) had significantly lower blast incidence and severity (1.23% and 3.33%) against untreated plants. Cocktail of Nativo and Trooper (Tricyclazole 75 wp) proved 2nd best curative measure. Application of Nativo (Tebuconazole 50% + Trifloxystrobin 25%) alone ranked third in its efficacy. The fungicide spray schedule covered booting, pre-heading and heading stages of wheat. The results indicate a mixture of Tebuconazole + Tricyclazole + Pyraclostrobin is more effective (97% blast reduction) and economic (BCR 1.45) than a single compound application in reducing incidence and severity of wheat blast.
 Int. J. Agril. Res. Innov. Tech. 11(1): 10-16, June 2021

Genotypic screening of wheat and their physiological responses under lead toxicity

Lead (Pb) is the second most harmful heavy metal contaminant in the environment and toxic for plant growth and development. Therefore, the identification and selection of plant genotypes tolerant to Pb stress are of great significance. In this study, twenty-six wheat lines (Triticum aestivum) were screened for Pb tolerance based on their morpho-physiological variations at the seedling stage with a rapid hydroponic technique using lead nitrate (Pb(NO3)2) at two concentrations (500 ?M and 1 mM) along with control. Wheat genotypes showed distinct variations in plant height, plant biomass and chlorophyll concentration in response to different concentrations of Pb. Considering all parameters, Akbar was found most tolerant (T) with minimum RS (2.97) to Pb stress, followed by BARI Gom-31 (3.45), Barkat (3.54) and Sufi (3.65), while BARI Gom-26 (10.14) was most sensitive (S) followed by Khude Gom (9.69), BARI Gom-30 (8.79), LalGom (8.76) and BARI Gom-32 respectively. More scores were seen in the remaining genotypes and were graded as moderately tolerant/resistant (MT) to Pb stress. Results showed that the resistant line had less damage to root and shoot characteristics along with chlorophyll score, thereby providing a hint about the Pb tolerance capacity of wheat genotypes at the seedling stage. Furthermore, findings indicate that Pb susceptibility in wheat is predominantly associated with a decrease in the Pb components of the root and shoot. We suggest Akbar as an elite genotype to cultivate or use in downstream studies on the basis of our findings to ensure an improved crop production relative to other varieties evaluated. These findings provide the necessary background for Pb cleansing and Pb-free wheat development for environment and health safety.

Evaluation of the Tolerance Ability of Wheat Genotypes to Drought Stress: Dissection through Culm-Reserves Contribution and Grain Filling Physiology

Drought stress is one of the limiting factors for grain filling and yield in wheat. The grain filling and determinants of individual grain weight depend on current assimilation and extent of remobilization of culm reserves to grains. A pot experiment was conducted with eight wheat cultivars at the Pot House to study the grain filling and the contributions of reserves in culm, including the sheath to grain yield under drought stress. Drought stress was enforced by restricting irrigation during the grain-filling period. The plants (tillers) were harvested at anthesis, milk-ripe, and maturity. The changes in dry weights of leaves, culm with sheath, spikes, and grains; and the contribution of culm reserves to grain yield were determined. Results revealed that drought stress considerably decreased the grain filling duration by 15–24% and grain yield by 11–34%. Further, drought-induced early leaf senescence and reduced total dry matter production indicate the minimum contribution of current assimilation to grain yield. The stress reduced the contribution of culm reserves, the water-soluble carbohydrates (WSCs), to the grains. The accumulation of culm WSCs reached peak at milk ripe stage in control, varied from 28.6 to 84 mg culm−1 and that significantly reduced in the range from 14.9 to 40.6 mg culm−1 in stressed plants. The residual culm WSCs in control and stressed plants varied from 1.23 to 8.12 and 1.00 to 3.40 mg g−1 culm dry mass, respectively. BARI Gom 24 exhibited a higher contribution of culm WSCs to grain yield under drought, while the lowest contribution was found in Kanchan. Considering culm reserves WSCs and their remobilization along with other studied traits, BARI Gom 24 showed greater drought tolerance and revealed potential to grow under water deficit conditions in comparison to other cultivars.