Mohammad Ashik Iqbal Khan - Academia.edu (original) (raw)
Papers by Mohammad Ashik Iqbal Khan
PloS one, Jun 18, 2024
Rice (Oryza sativa) stands as a crucial staple food worldwide, especially in Bangladesh, where it... more Rice (Oryza sativa) stands as a crucial staple food worldwide, especially in Bangladesh, where it ranks as the third-largest producer. However, intensified cultivation has made highyielding rice varieties susceptible to various biotic stresses, notably sheath blight caused by Rhizoctonia solani, which inflicts significant yield losses annually. Traditional fungicides, though effective, pose environmental and health risks. To address this, nanotechnology emerges as a promising avenue, leveraging the antimicrobial properties of nanoparticles like silver nanoparticles (AgNPs). This study explored the green synthesis of AgNPs using Ipomoea carnea leaf extract and silver nitrate (AgNO 3), and also examined their efficacy against sheath blight disease in rice. The biosynthesized AgNPs were characterized through various analytical techniques such as UV-vis spectrophotometer, X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Particle size analyzer, Zeta potential, Scanning Electron Microscope (SEM), Field Emission Scanning Electron Microscope (FESEM), Transmission Electron Microscope (TEM) for confirming their successful production and crystalline nature of nanoparticles. The results of UV-visible spectrophotometers revealed an absorption peak ranging from 421 to 434 nm, validated the synthesis of AgNPs in the solution. XRD, DLS, and TEM estimated AgNPs sizes were~45 nm, 66.2nm, and 46.38 to 73.81 nm, respectively. SEM and FESEM demonstrated that the synthesized AgNPs were spherical in shape. In vitro assays demonstrated the significant inhibitory effects of AgNPs on mycelial growth of Rhizoctonia solani, particularly at higher concentrations and pH levels. Further greenhouse and field experiments validated the antifungal efficacy of AgNPs against sheath blight disease in rice, exhibiting comparable effectiveness to commercial fungicides. The findings highlight the potential of AgNPs as a sustainable and effective alternative for managing rice sheath blight disease, offering a safer solution amidst environmental concerns associated with conventional fungicides.
Plant Health Progress, Mar 7, 2023
A total of seven seed-borne fungi were detected from forty rice (Oryzae sativa) seed samples (cv.... more A total of seven seed-borne fungi were detected from forty rice (Oryzae sativa) seed samples (cv. BR11 and BRRI dhan28) collected from two upazilas (Narshingdi Sadar and Shibpur) of Narshingdi district in Bangladesh. The identified species were Bipolaris oryzae, Alternaria padwickii, Sarocladium oryzae, Curvularia lunata, Aspergillus niger and Fusarium spp. The seed samples were composed of apparently healthy seed, spotted seed, discoloured seed, deformed seed, varietal mixture and chaffy grain. Prevalence of fungi and seed germination varied significantly with respect to variety and seed source. Seeds of rice variety BRRI dhan28 carried the lower infection of all the seed-borne fungi than the variety BR11. Seeds collected from Shibpur had higher seed-borne infection. An attempt has been made to control the seed-borne fungi by different plant extracts and chemicals. Garlic extract (1:1) dilution found best which successfully reduced seed-borne infection (80.3%) and also increased seed germination by 10.69% over control. Neem, allamanda and bishkatali extracts also increased seed germination 8.99%, 7.10% and 5.84%, respectively. Seed treating fungicides viz. Vitavax-200, Bavistin 50 WP and Captan were also tested to control seed-borne fungi. Seed treatment with Vitavax-200 @ 0.3% of seed weight eliminated all the seed-borne fungi and increased seed germination by 25.70% over control. Another chemical Bavistin also reduced seed-borne infection (88%) successfully and increased seed germination by 24.67% over control. Considering the high cost and deleterious effect of chemicals on environment, plant extracts may be recommended for controlling seed-borne fungal pathogens of rice as they are cheap, safe and eco-friendly.
Archives of Phytopathology and Plant Protection, Feb 25, 2016
Bacterial Blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo), a destructive disease of ric... more Bacterial Blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo), a destructive disease of rice. Altogether, 96 isolates of Xoo were collected from 19 rice growing districts of Bangladesh in irrigated and rainfed seasons during 2014 to assess pathotypic variation. Pathotypic analyses on a set of 12 Near Isogenic Lines (NILs) of rice containing resistance genes viz. Xa1, Xa2, Xa3, Xa4, Xa5, Xa7, Xa8, Xa10, Xa11, Xa13, Xa14 and Xa21 and two check varieties IR24 and TN1 by leaf clip-inoculation technique. A total of 24 pathotypes were identified based on their virulence patterns on NILs tested. Among these, pathotypes VII, XII, and XIV considered as major, containing maximum number of isolates, (9.38% each) frequently distributed in North to Mid-Eastern districts of Bangladesh. Most virulent pathotype I recorded from Habiganj and Brahmanbaria. This pathotypic variation explained the pathogenic relatedness of X. oryzae pv. oryzae populations from diverse geographic areas in Bangladesh.
Soil Science and Plant Nutrition, Nov 25, 2020
Genetic variations in the root traits of rice remain unexplored in relation to varietal groups an... more Genetic variations in the root traits of rice remain unexplored in relation to varietal groups and diverse ecosystems. Therefore, we evaluated 257 Bangladeshi accessions, which included landraces and improved varieties belonging to four ecotypes (Aus, Aman, Boro and Jhum), to understand genetic variations in the total root length (TRL), maximum root length and root number under different concentrations of ammonium and nitrate nitrogen in hydroponic culture. There were large variations in all traits across all nitrogen levels. Active elongation of individual roots of the landrace type across all nitrogen conditions suggested a higher potential for the uptake of nutrients by extending roots distribution in any nitrogen environment, while the active development of primary root primordia in the improved type in the presence of nitrate suggested a higher potential for the uptake of nitrate from the soil surface by extending roots distribution around soil surface. Cluster analysis classified the examined accessions into two groups according to their TRL: cluster I with a longer TRL and cluster II with a shorter TRL across all nitrogen conditions. Each of these groups was further divided into two subclusters: sub-cluster Ia, in which the longer TRL resulted from active development of primary root primordia, sub-cluster Ib, in which the longer TRL resulted from active elongation of individual roots, subcluster IIa, in which the shorter TRL resulted from severe reduction of the elongation of individual roots, and sub-cluster IIb, in which the shorter TRL resulted from a moderate reduction in the elongation of individual roots. Further investigation revealed a difference in the composition of these four sub-clusters among the four ecotypes, indicating that Aman was the most diverse ecotype, followed by Aus. The root traits of these promising accessions could be exploited in the future to understand genetic and physiological mechanism(s) of adaptation to diverse ecosystems.
Breeding Science, 2017
Genetic variation in blast resistance was clarified in 334 Bangladesh rice accessions from 4 majo... more Genetic variation in blast resistance was clarified in 334 Bangladesh rice accessions from 4 major ecotypes (Aus, Aman, Boro and Jhum). Cluster analysis of polymorphism data of 74 SSR markers separated these accessions into cluster I (corresponding to the Japonica Group) and cluster II (corresponding to the Indica Group). Cluster II accessions were represented with high frequency in all ecotypes. Cluster II was further subdivided into subclusters IIa and IIb. Subcluster IIa accessions were represented with high frequency in only Aus and Jhum ecotypes. Cluster I accessions were more frequent in the Aman ecotype than in other ecotypes. Distinct variations in resistance were found, and accessions were classified into 4 groups (A1, A2, B1 and B2) based on their reactions to standard differential blast isolates. The most susceptible group was A2 (which included susceptible variety Lijiangxintuanheigu, most of the differential varieties, and a few Bangladesh accessions), followed in order by A1, B2 and B1 (the most resistant). Accessions from 4 ecotypes fell with different frequencies into each of these resistance groups. These results demonstrated that Japonica Group accessions were found mainly in Aman, and Indica Group accessions were distributed across all ecotypes. Susceptible accessions were limited in Aus and Aman.
Bangladesh rice journal, Sep 29, 2017
Outbreak of false smut, caused by the fungus Ustilaginoidea virens has been recorded in recent ye... more Outbreak of false smut, caused by the fungus Ustilaginoidea virens has been recorded in recent years in the popular rice variety 'BRRI dhan49' from various parts of Bangladesh. Registered and/or recommended fungicides are not yet available for chemically controlling the disease. Consequently, uses of unregistered fungicides are common by the farmers for the management of the disease. The present study was, therefore, undertaken to identify effectiveness of any fungicides to control rice false smut disease. Seven synthetic foliar fungicides were evaluated in the naturally induced diseased plots. Each fungicide was applied as spray twice, at panicle initiation and at early flowering stage. Compared to the control (no fungicide application), the fungicide 'Controller 300 EC' reduced the hill infection by 57%, followed by 'Green 300 EC', 'Cuprofix 30 Disperss' and Diazole 300 EC, each of those suppressed the hill infection by 50%. While Cuprofix 30 Disperss, compared to the control, resulted in the lowest number of infected panicle per hill, it was statistically similar to rest of the fungicides except for Confidence 10 SL. Fungicides and control did not have any significant variation on the number of infected florets per panicle. With respect to per unit (hill infection × number of infected panicle per hill) disease suppression Controller 300 EC was the best. However, none of the fungicides reached the level of the disease suppression, the essential criterion for registration and/or recommendation of a fungicide under Bangladesh conditions. It is concluded that more multi-location and multi-season experiments will be required to reach a decisive conclusion on foliar chemical options for controlling rice false smut disease under Bangladesh conditions.
Bangladesh Journal of Plant Pathology, 2010
Bangladesh Journal of Plant Pathology, 2009
The virulence spectrum of 300 isolates of Xanthomonas oryzae pv. oryzae (Xoo), representing 17 di... more The virulence spectrum of 300 isolates of Xanthomonas oryzae pv. oryzae (Xoo), representing 17 districts of Punjab, Pakistan was elucidated through inoculation on a set of six rice IRRI-differentials. The virulence level was assessed by using principal component and cluster analysis. Among six principal components (PCs), PC-1 exhibited 59.3 % of the total variance. The highly virulent isolates clusters on the positive side of the ordination away from the point of intersection of PC1 and PC2 and classifies the Xoo isolates from slow disease to the highest disease causing entities. The 300 isolates were categorized into 29 pathotypes (Pt1-29) wherein the highly virulent pathotype (Pt-1), comprises of 39 Xoo isolates were widespread in 12 districts. The majority of Xoo isolates were moderately to least virulent (21.7-43 %) and average disease progress curves confirmed the field reactions of these pathotype clusters for an efficient recognition of Xoo isolates. Interaction of the pathogen with differentials harboring different resistant genes was well investigated in the current study
Pakistan Journal of Weed Science Research, 2015
An investigation was carried out to evaluate the performance of different weed management options... more An investigation was carried out to evaluate the performance of different weed management options regarding effective weed control, yield and yield contributing characters of three popular BRRI (Bangladesh Rice Research Institute) released aman varieties (BRRI dhan39, BRRI dhan49 and BR11) having different growth duration in the year of 2008 and 2009 at Bangladesh Rice Research Institute, regional station, Rajshahi. Weed management options were pre (Pretilachlor) and post emergence (Pyrozosulfuran-ethyl) herbicide, BRRI weeder, hand weeding (three times), pre and post emergence herbicide along with one supplement hand weeding and control (no weeding). Weed dry matter was significantly highest in control plot
A total of seven seed-borne fungi were detected from forty rice (Oryzae sativa) seed samples (cv.... more A total of seven seed-borne fungi were detected from forty rice (Oryzae sativa) seed samples (cv. BR11 and BRRI dhan28) collected from two upazilas (Narshingdi Sadar and Shibpur) of Narshingdi district in Bangladesh. The identified species were Bipolaris oryzae, Alternaria padwickii, Sarocladium oryzae, Curvularia lunata, Aspergillus niger and Fusarium spp. The seed samples were composed of apparently healthy seed, spotted seed, discoloured seed, deformed seed, varietal mixture and chaffy grain. Prevalence of fungi and seed germination varied significantly with respect to variety and seed source. Seeds of rice variety BRRI dhan28 carried the lower infection of all the seed-borne fungi than the variety BR11. Seeds collected from Shibpur had higher seed-borne infection. An attempt has been made to control the seed-borne fungi by different plant extracts and chemicals. Garlic extract (1:1) dilution found best which successfully reduced seed-borne infection (80.3%) and also increased se...
Bangladesh Rice Journal, 2021
A series of experiments were conducted in Plant Pathology Laboratory at Bangladesh Rice Research ... more A series of experiments were conducted in Plant Pathology Laboratory at Bangladesh Rice Research Institute (BRRI), Gazipur to know the efficacy of four bio-pesticides Recharge, Microtech1, Agroplus and Chitin and two bio-control agents (Trichoderma harzianum and Bacillus subtilis) on the major rice disease sheath blight (ShB) caused by Rhizoctonia solani in in-vitro and field condition. One fungicide Nativo (Tebuconazole 50% + Trifloxystrobin 25%) and one disease control (without any treatments) were also included as treatment for comparison. Radial mycelia growth of R. solani was mostly inhibited by a Bangladesh Trichoderma harzianum (BT1), Recharge and chemical fungicide Nativo 75 G at 48 hours of dual contact of R. solani and tested bio-pesticides or bio-control agents in in-vitro. The other bio-pesticides along with B. subtilis didn’t show any inhibition effect on the mycelia growth of R. solani which was similar to control (only water) treatment. Fungal inhibition 87.5% and 86....
Bangladesh Rice Journal, 2021
Strengthening the early warning system to forecast extreme weather and provide action-oriented ad... more Strengthening the early warning system to forecast extreme weather and provide action-oriented advisories may increase rice yield as well as enhance the income of the farmers through minimizing risks and losses, if proper use of the generated advisory is ensured. This study assessed the importance and impact of weather forecast based advisory service (WFBAS) in Bangladesh. Literature review and field experimental data were used in a sensitivity analysis to show the impact of WFBAS on rice production. Available literatures suggested that the weather based advisory service would enhance rice yield by around 6.7-10%, but the experimental findings revealed that yield advantage could be 21.48%. Besides, the adoption of this technology would reduce the cost of cultivation by 12%, whereas the aggregate impact would increase the farmers’ profit by 25%. In the sensitivity study, we considered the production and price of Aman and Boro seasons (actual and government procured prices for 2018-19...
![Research paper thumbnail of {"__content__"=>"Genetic variation in resistance to blast (Cavara) in rice (L.) germplasms of Bangladesh.", "i"=>[{"__content__"=>"Pyricularia oryzae"}, {"__content__"=>"Oryza sativa"}]}](https://attachments.academia-assets.com/107850646/thumbnails/1.jpg)
](Breeding science, 2017
Genetic variation in blast resistance was clarified in 334 Bangladesh rice accessions from 4 majo... more Genetic variation in blast resistance was clarified in 334 Bangladesh rice accessions from 4 major ecotypes (Aus, Aman, Boro and Jhum). Cluster analysis of polymorphism data of 74 SSR markers separated these accessions into cluster I (corresponding to the Japonica Group) and cluster II (corresponding to the Indica Group). Cluster II accessions were represented with high frequency in all ecotypes. Cluster II was further subdivided into subclusters IIa and IIb. Subcluster IIa accessions were represented with high frequency in only Aus and Jhum ecotypes. Cluster I accessions were more frequent in the Aman ecotype than in other ecotypes. Distinct variations in resistance were found, and accessions were classified into 4 groups (A1, A2, B1 and B2) based on their reactions to standard differential blast isolates. The most susceptible group was A2 (which included susceptible variety Lijiangxintuanheigu, most of the differential varieties, and a few Bangladesh accessions), followed in order...
- Screening of parental lines of three-line rice hybrid against Xanthomonas oryzae pv. Oryzae... more 2014) Screening of parental lines of three-line rice hybrid against Xanthomonas oryzae pv. Oryzae. Journal of Agricultural Technology 10(2):407-421. Experiments were conducted in pot in two seasons to screen some parental lines of hybrid rice against X. oryzae pv. oryzae. Fifty parental lines (Maintainer and Restorer lines) and 2 check varieties viz. 'Purbachi' and 'TN 1' as susceptible check were used as test materials. BXO9, the most virulent isolate of X. oryzae pv. oryzae in Bangladesh was used for inoculation. The inoculation was done by leaf clipping method. Based on lesion length on leaves and relative lesion length the parental lines were grouped into five clusters. In aman season (July to December) 14 days after inoculation, among the five clusters, cluster I contained 21 lines including 'Purbachi' and 'TN 1'. Cluster III comprised 4 lines which contain resistant parental line 'BR 168-2B-283R'. In boro season (November to May), on the...
Bangladesh Journal of Scientific and Industrial Research, 2007
A study was conducted at the Farming Systems Research and Development (FSR&D) site of Bangladesh ... more A study was conducted at the Farming Systems Research and Development (FSR&D) site of Bangladesh Rice Research Institute (BRRI) during kharif-I, 1999 to find the agronomic management followed for lady's finger cultivation by the different categories of farmers and to understand its production, consumption and disposal pattern together with its economy. Technical knowledge was provided to the farmers for growing lady's finger. Farmers grew the crop with their own management and resources. Variation was found in the date of sowing, rate of fertilizer application and number of irrigation. The highest pod yield was associated with better agronomic management that resulted higher gross margin. Lady's finger production, consumption and selling were increased from April to June with a peak in the month of June. Lady's finger consumption was highest per head in case of medium farmer and was decreased from medium farmer to marginal one. The utilization of money earned from la...
Bangladesh Journal of Agricultural Research, 2012
An experiment was carried out at the Bangladesh Agricultural University, Mymensingh during Octobe... more An experiment was carried out at the Bangladesh Agricultural University, Mymensingh during October 2005 to March 2007 to study the effect of different soil water levels on the physio-morphological features of ten Chilli (Capsicum annuum L.) accessions viz. C-0277, C-0297, BM-1, C-0100, BM-2, C-0265, C- 0272, C-0275, BM-3, and C-0271. The experiment was set up in pots under glasshouse condition. The water treatments were applied at 4 vegetative growth stages following withholding method (crude method) starting from 25 days after sowing and thereafter at every 7 days interval until final stage. The water treatments applied were W1 = watering once a day; W2 = watering at 4 days interval; W3 = watering at 8 days of interval, and W0 = no watering. Moisture capacity of polybag (analogous to field capacity) was determined by subtracting leached water from the original amount of water applied. In most of the parameters studied, W2 gave the highest value, W1 and W0 gave the lowest, while W3 ...
Field Crops Research, 2009
Conventional tilled transplanting, a widely practiced method of rice (Oryza sativa L.) establishm... more Conventional tilled transplanting, a widely practiced method of rice (Oryza sativa L.) establishment in puddled soils in rice-rice and rice-wheat (Triticum aestivum L.) systems in Asia, requires a large amount of labor and water, which are becoming scarce and expensive. Growing more food with the same production costs or even reduced costs and sustaining the quality of the natural resource base are a major concern. On-farm trials were conducted in Chuadanga District of Bangladesh during the wet season as monsoon rice (aman) and during the dry season as winter rice (boro) in 2006-07 to evaluate the effects of establishment methods with improved crop management on productivity, resource (land, water, and labor) use, and economic return. Rice was established by sowing in line with a drum seeder on conventional tilled puddled soils (CT-DrumR) and by transplanting in line on the day of CT-DrumR (CT-TPR1) and 30 and 35 days after CT-DrumR (CT-TPR2) in aman and boro seasons, respectively. Farmers' usual transplanting time corresponds to the day of CT-TPR2. Grain yields in CT-DrumR and CT-TPR2 were similar but the crop occupied the main field 22-24 days longer in CT-DrumR than in CT-TPR2, resulting in lower productivity (45 kg grain ha À1 day À1 vs. 55 kg grain ha À1 day À1) in both seasons. Drum-seeded rice matured earlier by 8 and 11 days, received 12% and 6% less irrigation water, saved 19 and 24 persondays ha À1 , and gave higher gross margins of 6% and 4% but input costs increased by 20% and 12% than CT-TPR2 in aman and boro seasons, respectively. There is a need to examine these benefits of drum-seeded rice in relation to the feasibility of adoption by farmers.
Bangladesh Rice Journal, 2017
Rice false smut (RFSm), considered as a minor importance, has become a serious disease in many ri... more Rice false smut (RFSm), considered as a minor importance, has become a serious disease in many rice growing areas of Bangladesh and other parts of the world. Many aspects of its epidemiology still remained unclear, notable the life cycle of RFSm pathogen, its infection site and the smut ball formation on infected panicles. Present research was undertaken to investigate the density and distribution of false smut balls on infected rice panicles aiding to understand on how severe the disease can be in a rice-ecosystem, on which position the smut balls form on infected panicles and likely yield reduction from such disease severity. This study included field observation of natural RFSm infection during 2014, 2015 and 2016, and simulated infection during 2015 in T. Aman rice in the experimental farm of the Bangladesh Rice Research Institute (BRRI), Gazipur, Bangladesh. While the number of smut balls reached as many as 136 (recorded in one panicle in 2015), the study shows there was 81, 54...
PloS one, Jun 18, 2024
Rice (Oryza sativa) stands as a crucial staple food worldwide, especially in Bangladesh, where it... more Rice (Oryza sativa) stands as a crucial staple food worldwide, especially in Bangladesh, where it ranks as the third-largest producer. However, intensified cultivation has made highyielding rice varieties susceptible to various biotic stresses, notably sheath blight caused by Rhizoctonia solani, which inflicts significant yield losses annually. Traditional fungicides, though effective, pose environmental and health risks. To address this, nanotechnology emerges as a promising avenue, leveraging the antimicrobial properties of nanoparticles like silver nanoparticles (AgNPs). This study explored the green synthesis of AgNPs using Ipomoea carnea leaf extract and silver nitrate (AgNO 3), and also examined their efficacy against sheath blight disease in rice. The biosynthesized AgNPs were characterized through various analytical techniques such as UV-vis spectrophotometer, X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Particle size analyzer, Zeta potential, Scanning Electron Microscope (SEM), Field Emission Scanning Electron Microscope (FESEM), Transmission Electron Microscope (TEM) for confirming their successful production and crystalline nature of nanoparticles. The results of UV-visible spectrophotometers revealed an absorption peak ranging from 421 to 434 nm, validated the synthesis of AgNPs in the solution. XRD, DLS, and TEM estimated AgNPs sizes were~45 nm, 66.2nm, and 46.38 to 73.81 nm, respectively. SEM and FESEM demonstrated that the synthesized AgNPs were spherical in shape. In vitro assays demonstrated the significant inhibitory effects of AgNPs on mycelial growth of Rhizoctonia solani, particularly at higher concentrations and pH levels. Further greenhouse and field experiments validated the antifungal efficacy of AgNPs against sheath blight disease in rice, exhibiting comparable effectiveness to commercial fungicides. The findings highlight the potential of AgNPs as a sustainable and effective alternative for managing rice sheath blight disease, offering a safer solution amidst environmental concerns associated with conventional fungicides.
Plant Health Progress, Mar 7, 2023
A total of seven seed-borne fungi were detected from forty rice (Oryzae sativa) seed samples (cv.... more A total of seven seed-borne fungi were detected from forty rice (Oryzae sativa) seed samples (cv. BR11 and BRRI dhan28) collected from two upazilas (Narshingdi Sadar and Shibpur) of Narshingdi district in Bangladesh. The identified species were Bipolaris oryzae, Alternaria padwickii, Sarocladium oryzae, Curvularia lunata, Aspergillus niger and Fusarium spp. The seed samples were composed of apparently healthy seed, spotted seed, discoloured seed, deformed seed, varietal mixture and chaffy grain. Prevalence of fungi and seed germination varied significantly with respect to variety and seed source. Seeds of rice variety BRRI dhan28 carried the lower infection of all the seed-borne fungi than the variety BR11. Seeds collected from Shibpur had higher seed-borne infection. An attempt has been made to control the seed-borne fungi by different plant extracts and chemicals. Garlic extract (1:1) dilution found best which successfully reduced seed-borne infection (80.3%) and also increased seed germination by 10.69% over control. Neem, allamanda and bishkatali extracts also increased seed germination 8.99%, 7.10% and 5.84%, respectively. Seed treating fungicides viz. Vitavax-200, Bavistin 50 WP and Captan were also tested to control seed-borne fungi. Seed treatment with Vitavax-200 @ 0.3% of seed weight eliminated all the seed-borne fungi and increased seed germination by 25.70% over control. Another chemical Bavistin also reduced seed-borne infection (88%) successfully and increased seed germination by 24.67% over control. Considering the high cost and deleterious effect of chemicals on environment, plant extracts may be recommended for controlling seed-borne fungal pathogens of rice as they are cheap, safe and eco-friendly.
Archives of Phytopathology and Plant Protection, Feb 25, 2016
Bacterial Blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo), a destructive disease of ric... more Bacterial Blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo), a destructive disease of rice. Altogether, 96 isolates of Xoo were collected from 19 rice growing districts of Bangladesh in irrigated and rainfed seasons during 2014 to assess pathotypic variation. Pathotypic analyses on a set of 12 Near Isogenic Lines (NILs) of rice containing resistance genes viz. Xa1, Xa2, Xa3, Xa4, Xa5, Xa7, Xa8, Xa10, Xa11, Xa13, Xa14 and Xa21 and two check varieties IR24 and TN1 by leaf clip-inoculation technique. A total of 24 pathotypes were identified based on their virulence patterns on NILs tested. Among these, pathotypes VII, XII, and XIV considered as major, containing maximum number of isolates, (9.38% each) frequently distributed in North to Mid-Eastern districts of Bangladesh. Most virulent pathotype I recorded from Habiganj and Brahmanbaria. This pathotypic variation explained the pathogenic relatedness of X. oryzae pv. oryzae populations from diverse geographic areas in Bangladesh.
Soil Science and Plant Nutrition, Nov 25, 2020
Genetic variations in the root traits of rice remain unexplored in relation to varietal groups an... more Genetic variations in the root traits of rice remain unexplored in relation to varietal groups and diverse ecosystems. Therefore, we evaluated 257 Bangladeshi accessions, which included landraces and improved varieties belonging to four ecotypes (Aus, Aman, Boro and Jhum), to understand genetic variations in the total root length (TRL), maximum root length and root number under different concentrations of ammonium and nitrate nitrogen in hydroponic culture. There were large variations in all traits across all nitrogen levels. Active elongation of individual roots of the landrace type across all nitrogen conditions suggested a higher potential for the uptake of nutrients by extending roots distribution in any nitrogen environment, while the active development of primary root primordia in the improved type in the presence of nitrate suggested a higher potential for the uptake of nitrate from the soil surface by extending roots distribution around soil surface. Cluster analysis classified the examined accessions into two groups according to their TRL: cluster I with a longer TRL and cluster II with a shorter TRL across all nitrogen conditions. Each of these groups was further divided into two subclusters: sub-cluster Ia, in which the longer TRL resulted from active development of primary root primordia, sub-cluster Ib, in which the longer TRL resulted from active elongation of individual roots, subcluster IIa, in which the shorter TRL resulted from severe reduction of the elongation of individual roots, and sub-cluster IIb, in which the shorter TRL resulted from a moderate reduction in the elongation of individual roots. Further investigation revealed a difference in the composition of these four sub-clusters among the four ecotypes, indicating that Aman was the most diverse ecotype, followed by Aus. The root traits of these promising accessions could be exploited in the future to understand genetic and physiological mechanism(s) of adaptation to diverse ecosystems.
Breeding Science, 2017
Genetic variation in blast resistance was clarified in 334 Bangladesh rice accessions from 4 majo... more Genetic variation in blast resistance was clarified in 334 Bangladesh rice accessions from 4 major ecotypes (Aus, Aman, Boro and Jhum). Cluster analysis of polymorphism data of 74 SSR markers separated these accessions into cluster I (corresponding to the Japonica Group) and cluster II (corresponding to the Indica Group). Cluster II accessions were represented with high frequency in all ecotypes. Cluster II was further subdivided into subclusters IIa and IIb. Subcluster IIa accessions were represented with high frequency in only Aus and Jhum ecotypes. Cluster I accessions were more frequent in the Aman ecotype than in other ecotypes. Distinct variations in resistance were found, and accessions were classified into 4 groups (A1, A2, B1 and B2) based on their reactions to standard differential blast isolates. The most susceptible group was A2 (which included susceptible variety Lijiangxintuanheigu, most of the differential varieties, and a few Bangladesh accessions), followed in order by A1, B2 and B1 (the most resistant). Accessions from 4 ecotypes fell with different frequencies into each of these resistance groups. These results demonstrated that Japonica Group accessions were found mainly in Aman, and Indica Group accessions were distributed across all ecotypes. Susceptible accessions were limited in Aus and Aman.
Bangladesh rice journal, Sep 29, 2017
Outbreak of false smut, caused by the fungus Ustilaginoidea virens has been recorded in recent ye... more Outbreak of false smut, caused by the fungus Ustilaginoidea virens has been recorded in recent years in the popular rice variety 'BRRI dhan49' from various parts of Bangladesh. Registered and/or recommended fungicides are not yet available for chemically controlling the disease. Consequently, uses of unregistered fungicides are common by the farmers for the management of the disease. The present study was, therefore, undertaken to identify effectiveness of any fungicides to control rice false smut disease. Seven synthetic foliar fungicides were evaluated in the naturally induced diseased plots. Each fungicide was applied as spray twice, at panicle initiation and at early flowering stage. Compared to the control (no fungicide application), the fungicide 'Controller 300 EC' reduced the hill infection by 57%, followed by 'Green 300 EC', 'Cuprofix 30 Disperss' and Diazole 300 EC, each of those suppressed the hill infection by 50%. While Cuprofix 30 Disperss, compared to the control, resulted in the lowest number of infected panicle per hill, it was statistically similar to rest of the fungicides except for Confidence 10 SL. Fungicides and control did not have any significant variation on the number of infected florets per panicle. With respect to per unit (hill infection × number of infected panicle per hill) disease suppression Controller 300 EC was the best. However, none of the fungicides reached the level of the disease suppression, the essential criterion for registration and/or recommendation of a fungicide under Bangladesh conditions. It is concluded that more multi-location and multi-season experiments will be required to reach a decisive conclusion on foliar chemical options for controlling rice false smut disease under Bangladesh conditions.
Bangladesh Journal of Plant Pathology, 2010
Bangladesh Journal of Plant Pathology, 2009
The virulence spectrum of 300 isolates of Xanthomonas oryzae pv. oryzae (Xoo), representing 17 di... more The virulence spectrum of 300 isolates of Xanthomonas oryzae pv. oryzae (Xoo), representing 17 districts of Punjab, Pakistan was elucidated through inoculation on a set of six rice IRRI-differentials. The virulence level was assessed by using principal component and cluster analysis. Among six principal components (PCs), PC-1 exhibited 59.3 % of the total variance. The highly virulent isolates clusters on the positive side of the ordination away from the point of intersection of PC1 and PC2 and classifies the Xoo isolates from slow disease to the highest disease causing entities. The 300 isolates were categorized into 29 pathotypes (Pt1-29) wherein the highly virulent pathotype (Pt-1), comprises of 39 Xoo isolates were widespread in 12 districts. The majority of Xoo isolates were moderately to least virulent (21.7-43 %) and average disease progress curves confirmed the field reactions of these pathotype clusters for an efficient recognition of Xoo isolates. Interaction of the pathogen with differentials harboring different resistant genes was well investigated in the current study
Pakistan Journal of Weed Science Research, 2015
An investigation was carried out to evaluate the performance of different weed management options... more An investigation was carried out to evaluate the performance of different weed management options regarding effective weed control, yield and yield contributing characters of three popular BRRI (Bangladesh Rice Research Institute) released aman varieties (BRRI dhan39, BRRI dhan49 and BR11) having different growth duration in the year of 2008 and 2009 at Bangladesh Rice Research Institute, regional station, Rajshahi. Weed management options were pre (Pretilachlor) and post emergence (Pyrozosulfuran-ethyl) herbicide, BRRI weeder, hand weeding (three times), pre and post emergence herbicide along with one supplement hand weeding and control (no weeding). Weed dry matter was significantly highest in control plot
A total of seven seed-borne fungi were detected from forty rice (Oryzae sativa) seed samples (cv.... more A total of seven seed-borne fungi were detected from forty rice (Oryzae sativa) seed samples (cv. BR11 and BRRI dhan28) collected from two upazilas (Narshingdi Sadar and Shibpur) of Narshingdi district in Bangladesh. The identified species were Bipolaris oryzae, Alternaria padwickii, Sarocladium oryzae, Curvularia lunata, Aspergillus niger and Fusarium spp. The seed samples were composed of apparently healthy seed, spotted seed, discoloured seed, deformed seed, varietal mixture and chaffy grain. Prevalence of fungi and seed germination varied significantly with respect to variety and seed source. Seeds of rice variety BRRI dhan28 carried the lower infection of all the seed-borne fungi than the variety BR11. Seeds collected from Shibpur had higher seed-borne infection. An attempt has been made to control the seed-borne fungi by different plant extracts and chemicals. Garlic extract (1:1) dilution found best which successfully reduced seed-borne infection (80.3%) and also increased se...
Bangladesh Rice Journal, 2021
A series of experiments were conducted in Plant Pathology Laboratory at Bangladesh Rice Research ... more A series of experiments were conducted in Plant Pathology Laboratory at Bangladesh Rice Research Institute (BRRI), Gazipur to know the efficacy of four bio-pesticides Recharge, Microtech1, Agroplus and Chitin and two bio-control agents (Trichoderma harzianum and Bacillus subtilis) on the major rice disease sheath blight (ShB) caused by Rhizoctonia solani in in-vitro and field condition. One fungicide Nativo (Tebuconazole 50% + Trifloxystrobin 25%) and one disease control (without any treatments) were also included as treatment for comparison. Radial mycelia growth of R. solani was mostly inhibited by a Bangladesh Trichoderma harzianum (BT1), Recharge and chemical fungicide Nativo 75 G at 48 hours of dual contact of R. solani and tested bio-pesticides or bio-control agents in in-vitro. The other bio-pesticides along with B. subtilis didn’t show any inhibition effect on the mycelia growth of R. solani which was similar to control (only water) treatment. Fungal inhibition 87.5% and 86....
Bangladesh Rice Journal, 2021
Strengthening the early warning system to forecast extreme weather and provide action-oriented ad... more Strengthening the early warning system to forecast extreme weather and provide action-oriented advisories may increase rice yield as well as enhance the income of the farmers through minimizing risks and losses, if proper use of the generated advisory is ensured. This study assessed the importance and impact of weather forecast based advisory service (WFBAS) in Bangladesh. Literature review and field experimental data were used in a sensitivity analysis to show the impact of WFBAS on rice production. Available literatures suggested that the weather based advisory service would enhance rice yield by around 6.7-10%, but the experimental findings revealed that yield advantage could be 21.48%. Besides, the adoption of this technology would reduce the cost of cultivation by 12%, whereas the aggregate impact would increase the farmers’ profit by 25%. In the sensitivity study, we considered the production and price of Aman and Boro seasons (actual and government procured prices for 2018-19...
Breeding science, 2017
Genetic variation in blast resistance was clarified in 334 Bangladesh rice accessions from 4 majo... more Genetic variation in blast resistance was clarified in 334 Bangladesh rice accessions from 4 major ecotypes (Aus, Aman, Boro and Jhum). Cluster analysis of polymorphism data of 74 SSR markers separated these accessions into cluster I (corresponding to the Japonica Group) and cluster II (corresponding to the Indica Group). Cluster II accessions were represented with high frequency in all ecotypes. Cluster II was further subdivided into subclusters IIa and IIb. Subcluster IIa accessions were represented with high frequency in only Aus and Jhum ecotypes. Cluster I accessions were more frequent in the Aman ecotype than in other ecotypes. Distinct variations in resistance were found, and accessions were classified into 4 groups (A1, A2, B1 and B2) based on their reactions to standard differential blast isolates. The most susceptible group was A2 (which included susceptible variety Lijiangxintuanheigu, most of the differential varieties, and a few Bangladesh accessions), followed in order...
- Screening of parental lines of three-line rice hybrid against Xanthomonas oryzae pv. Oryzae... more 2014) Screening of parental lines of three-line rice hybrid against Xanthomonas oryzae pv. Oryzae. Journal of Agricultural Technology 10(2):407-421. Experiments were conducted in pot in two seasons to screen some parental lines of hybrid rice against X. oryzae pv. oryzae. Fifty parental lines (Maintainer and Restorer lines) and 2 check varieties viz. 'Purbachi' and 'TN 1' as susceptible check were used as test materials. BXO9, the most virulent isolate of X. oryzae pv. oryzae in Bangladesh was used for inoculation. The inoculation was done by leaf clipping method. Based on lesion length on leaves and relative lesion length the parental lines were grouped into five clusters. In aman season (July to December) 14 days after inoculation, among the five clusters, cluster I contained 21 lines including 'Purbachi' and 'TN 1'. Cluster III comprised 4 lines which contain resistant parental line 'BR 168-2B-283R'. In boro season (November to May), on the...
Bangladesh Journal of Scientific and Industrial Research, 2007
A study was conducted at the Farming Systems Research and Development (FSR&D) site of Bangladesh ... more A study was conducted at the Farming Systems Research and Development (FSR&D) site of Bangladesh Rice Research Institute (BRRI) during kharif-I, 1999 to find the agronomic management followed for lady's finger cultivation by the different categories of farmers and to understand its production, consumption and disposal pattern together with its economy. Technical knowledge was provided to the farmers for growing lady's finger. Farmers grew the crop with their own management and resources. Variation was found in the date of sowing, rate of fertilizer application and number of irrigation. The highest pod yield was associated with better agronomic management that resulted higher gross margin. Lady's finger production, consumption and selling were increased from April to June with a peak in the month of June. Lady's finger consumption was highest per head in case of medium farmer and was decreased from medium farmer to marginal one. The utilization of money earned from la...
Bangladesh Journal of Agricultural Research, 2012
An experiment was carried out at the Bangladesh Agricultural University, Mymensingh during Octobe... more An experiment was carried out at the Bangladesh Agricultural University, Mymensingh during October 2005 to March 2007 to study the effect of different soil water levels on the physio-morphological features of ten Chilli (Capsicum annuum L.) accessions viz. C-0277, C-0297, BM-1, C-0100, BM-2, C-0265, C- 0272, C-0275, BM-3, and C-0271. The experiment was set up in pots under glasshouse condition. The water treatments were applied at 4 vegetative growth stages following withholding method (crude method) starting from 25 days after sowing and thereafter at every 7 days interval until final stage. The water treatments applied were W1 = watering once a day; W2 = watering at 4 days interval; W3 = watering at 8 days of interval, and W0 = no watering. Moisture capacity of polybag (analogous to field capacity) was determined by subtracting leached water from the original amount of water applied. In most of the parameters studied, W2 gave the highest value, W1 and W0 gave the lowest, while W3 ...
Field Crops Research, 2009
Conventional tilled transplanting, a widely practiced method of rice (Oryza sativa L.) establishm... more Conventional tilled transplanting, a widely practiced method of rice (Oryza sativa L.) establishment in puddled soils in rice-rice and rice-wheat (Triticum aestivum L.) systems in Asia, requires a large amount of labor and water, which are becoming scarce and expensive. Growing more food with the same production costs or even reduced costs and sustaining the quality of the natural resource base are a major concern. On-farm trials were conducted in Chuadanga District of Bangladesh during the wet season as monsoon rice (aman) and during the dry season as winter rice (boro) in 2006-07 to evaluate the effects of establishment methods with improved crop management on productivity, resource (land, water, and labor) use, and economic return. Rice was established by sowing in line with a drum seeder on conventional tilled puddled soils (CT-DrumR) and by transplanting in line on the day of CT-DrumR (CT-TPR1) and 30 and 35 days after CT-DrumR (CT-TPR2) in aman and boro seasons, respectively. Farmers' usual transplanting time corresponds to the day of CT-TPR2. Grain yields in CT-DrumR and CT-TPR2 were similar but the crop occupied the main field 22-24 days longer in CT-DrumR than in CT-TPR2, resulting in lower productivity (45 kg grain ha À1 day À1 vs. 55 kg grain ha À1 day À1) in both seasons. Drum-seeded rice matured earlier by 8 and 11 days, received 12% and 6% less irrigation water, saved 19 and 24 persondays ha À1 , and gave higher gross margins of 6% and 4% but input costs increased by 20% and 12% than CT-TPR2 in aman and boro seasons, respectively. There is a need to examine these benefits of drum-seeded rice in relation to the feasibility of adoption by farmers.
Bangladesh Rice Journal, 2017
Rice false smut (RFSm), considered as a minor importance, has become a serious disease in many ri... more Rice false smut (RFSm), considered as a minor importance, has become a serious disease in many rice growing areas of Bangladesh and other parts of the world. Many aspects of its epidemiology still remained unclear, notable the life cycle of RFSm pathogen, its infection site and the smut ball formation on infected panicles. Present research was undertaken to investigate the density and distribution of false smut balls on infected rice panicles aiding to understand on how severe the disease can be in a rice-ecosystem, on which position the smut balls form on infected panicles and likely yield reduction from such disease severity. This study included field observation of natural RFSm infection during 2014, 2015 and 2016, and simulated infection during 2015 in T. Aman rice in the experimental farm of the Bangladesh Rice Research Institute (BRRI), Gazipur, Bangladesh. While the number of smut balls reached as many as 136 (recorded in one panicle in 2015), the study shows there was 81, 54...