Root Dip Research Articles

Synergistic application of melatonin and silicon oxide nanoparticles modulates reactive oxygen species generation and the antioxidant defense system: a strategy for cadmium tolerance in rice.

Unfavorable environmental conditions pose a major barrier to sustainable agriculture. Among the various innovative strategies developed to protect plants from abiotic stress, the use of phytohormones and nanoparticles as "stress mitigators" has emerged as one of the most important and promising approaches. The objective of this study was to observe the protective role of melatonin (Mel) and silicon oxide nanoparticles (SiO-NPs) in rice (Oryza sativa L.) seedlings under cadmium (Cd) stress. Rice seedlings have reduced growth and phytochemical attributes when grown in Cd-contaminated (0.8 mM) pots. Seedlings under Cd stress had 38% less shoot length (SL), 53% total soluble sugar (TSS) and 57% protein content. However, superoxide dismutase (SOD), hydrogen peroxide (H2O2) and malondialdehyde (MDA) increased by 51%, 37% and 34%, respectively, under Cd stress. Beside this, activities such as peroxidase (POX) also elevated in the plants subjected with Cd-stress. In contrast, Mel (100 µm) as foliar spray and SiO-NPs (100 mg/L) as root dipping reduced oxidative stress in rice seedlings under Cd stress by reducing reactive oxygen species (ROS) generation. Furthermore, the application of Mel and/or SiO-NPs significantly increased the activity of antioxidative enzymes that scavenge ROS. The combined application of SiO-NPs and Mel increased growth, gas exchange and photosynthetic attributes, chlorophyll value, and protein content. It causes alleviation in the activity of SOD, CAT and POX by 73%, 62% and 65%, respectively. Overall, this study findings show that Mel and/or SiO-NPs can potentially protect the rice crop against oxidative damage under Cd stress.

Potentiality of Formulated Pseudomonas Fluorescens and Bacillus Subtilis for the Management of Sheath Blight Disease of Rice Under Field Condition

Rice production is severely affected by sheath blight disease in Bangladesh which is caused by a fungus Rhizoctonia solani that is still merely managed by synthetic chemical fungicides. In this study, different isolates of Pseudomonas fluorescens and Bacillus subtilis were evaluated to assess their inhibitory effects against R. solani both in- vitro and field condition following dual culture method in order to formulate technique for the management of sheath blight of rice. Among all the isolates, P. fluorescens (Pf- 7 and Pf- 8) and B. subtilis (Bs-17 and Bs-21) showed the highest in –vitro mycelial growth suppression of the pathogen. Based on the in-vitro mycelial growth suppression performance, fourteen treatments combinations, either single or in consortia of antagonistic bacteria in talc-based formulations were applied by root dipping. All the formulated bacterial isolates showed significant reduction in disease and severity compared to untreated control and chemical fungicide. At 90 DAT, both the disease incidence and severity were found lowest in T11 (31.67 % and 37.33 % respectively) where the seedlings were treated for 24 hours with consortium of Pf-7 + Pf- 8 formulated in talc followed by in T12 (32.00 % and 38.00 %) where the seedlings were treated for 24 hours with consortium of Bs-17 + Bs-21 formulated in talc respectively. Vegetative and yield parameters were also significantly increased in both T11 and T12. The highest yield as well as Benefit Cost Ratio (BCR) were found in T11 (2.50 kg/ m2 and 2.20) followed by T12 (2.49 kg/m2 and 2.18). Thus, the consortia of bacterial isolates (Pseudomonas fluorescens and Bacillus subtilis) with seedling dipping time for 24 hour represents a promising alternative to chemical fungicides for the management of sheath blight of rice in field condition. J Bangladesh Agril Univ 22(3): 342-351, 2024

Strategic management of nano-fertilizers for sustainable rice yield, grain quality, and soil health

Conventional fertilizers, although widely available, are relatively low in nutrient use efficiency and cause serious environmental concerns like eutrophication, greenhouse gas (GHG) emissions, nitrate poisoning, and soil pollution. With this in mind, a randomized block design (RBD) experiment was conducted in an experimental field taking 10 treatments and 3 replications to investigate the effects of integrated approaches of nano-formulated DAP fertilizer applications on rice growth, yield, and nutrient use efficiency over conventional approaches. The result revealed that plant height, panicle length, number of tillers hill−1, total number of grain panicle−1, and root length were maximum in T10 treatment (50% of the soil test recommended doses (STD) for N and P + seedling root dipping (SRD) with nano DAP at 5 mL L−1 + twice foliar sprays (FS) with nano DAP at 4 mL L−1 at 25 and 45 DAT (date after transplanting). The highest mean grain yields (4.12 and 4.05 Mg ha−1) and nutrient uptake were recorded in the T2 treatment (100% STD), but this was at par with T10 treatment. The highest benefit–cost ratio (2.26) was recorded in T10, which was 3.5% higher than T2. N and P agronomic use efficiency (AUE) ranged from 7.5% to 31.5% and 15% to 63%, and recovery efficiency (RE) ranged from 30% to 94.2% and 11.2% to 90.4%. The highest nutrient use efficiency was recorded with T10, followed by T9, and lowest in T4. Post-harvest soil pH and available N and P were significantly highest in T10. Soil MBC, MBN, MBP, urease, and phosphatase activity were found significantly higher in T2, followed by T10. The integrated application of 50% STD for N and P + SRD with nano DAP at 5 mL L-1 + twice FS with nano DAP at 4 mL L−1 at 25 and 45 DAT application can be a suitable substitute for conventional DAP and urea for rice in climate-smart agriculture as it possibly reduces environmental pollution while undisturbing crop yield over the 100% STD.

Assay of Front-Line Demonstration on Integrated Pest and Disease Management (IPDM) in Rice in the Vikarabad District of Telangana, India

Rice crop is attacked by various insects and diseases in spite of using pesticides, but relaying only on synthetic pesticides usage resulted into disrupt the natural balance between crop pests and their existed natural enemies. Integrated pest and disease management (IDPM) is a concept which is blended with all possible proven technologies like Cultural, Mechanical, Biological and Chemical methods. Front line demonstration on Integrated Pest and Disease Management in rice was taken up in farmers fields during kharif season of two consecutive years of 2021 and 2022 by DAATTC, Tandur in Vikarabad district of Telangana. Study revealed that seed treatment with Carbendazim @3gm/kg seed, seedling root dip with Pseudomonas species 10gm /lit of water, application of Carbofuran granules @160g/cent nursery, installation of pheromone traps, formation of alley ways and need based application of fertilizers and pesticides reduced the pest like Stem borer, BPH, Leaf folder and Blast disease significantly compared to farmers practice. Mean higher yield was recorded in demo field 6065 kg/ha compared to 5795 kg/ha in check, and showed 4.6 per cent yield increases in demonstration fields.

Application of silver nanoparticles synthesized from the calli of Centella asiatica for the management of Meloidogyne arenaria infection in cowpea plants

The green synthesis of AgNPs from the calli extract of Centella asiatica was confirmed by the detailed analysis of UV–Vis spectroscopy, Scanning electron microscopy (SEM), Energy dispersive X-ray analysis (EDAX), Transmission electron microscopy (TEM), Fourier Transform Infrared Spectroscopy (FT-IR) which revealed the size, shape, chemical composition and functional groups involved in the AgNPs formation.The in-vitro raised cowpea plants were given root dip treatment in Murashige and Skoog (MS) suspension medium supplemented with LC50- 75 mg/mL AgNPs followed by their transfer to glass house conditions for acclimatization. To evaluate the efficiency of root dip treatment, the acclimatized plants were inoculated with 2000 J2s of M. arenaria and the plants were observed on weekly basis. A differential growth response was observed from the cowpea plants under glass house conditions. A treatment plan designed showed that P4 plants showed a significant defense response against the biotic stress of M. arenaria as indicated by the percentage response of several growth parameters such as- plant height of 49.22 ± 0.89 %, plant fresh mass of 46.12 ± 0.83 %, plant dry mass of 9.3 ± 0.17 % and nodule number of 38 ± 0.68 % were reported in P4 plants after 6 weeks of J2s inoculation.Confocal microscopy of root sections of P3 cowpea plants revealed the presence of M. arenaria J2s in the cortical and provascular regions, however, in case of P4 plants an intact cellular structure was maintained. The application of AgNP didn't show any toxic effect on the growth of plant.

Endophytic bacteria nano-formula: A promotor for plant growth and systemic acquired resistance against sheath blight disease on rice

Sheath blight disease significantly affected growing rice crop and caused yield losses. This study identified two endophyte bacterial isolates, Bacillus subtilis, and Pseudomonas brassicacearum subsp. Neoaurantiaca, significantly inhibit Rhizoctonia solani AG1 IA mycelial growth. Further, the analysis of the culture filtrate for the two identified bacteria recorded a set of bioactive components that have antifungal activity and enhance plant growth. We prepared a novel nano-formula using the advantages of nano natural charcoal (NCNPs) as an organic matter and enriched with alginate to improve the nano-formula porosity and keep the viability of the loaded bacteria up to 18 months. Two methods (soil application and root dipping) were used to evaluate the impact of bacteria nano-formula on rice growth and rice sheath blight (ShB) disease under artificial inoculation with R. solani at greenhouse conditions. The root dipping with P. brassicacearum NCNPs alginate (PBNF-R) and B. subtillus NCNPs alginate (BSNF-R) recorded the highest performance in the rice growth traits, and a high control level of the rice ShB disease by decreasing relative lesion height and percent disease index. In addition, PBNF-R and BSNF-R increase the defense-related enzyme production in the plant cell (peroxidase, polyphenol oxidase, and phenylalanine ammonia‐lyase) and, consequently, the plant immunity. Moreover, both upregulate the gene expression levels of OsNPR1, OsWRKY45, OsPR10, and OsAOS2, which are related to the plant defense mechanism. Finally, here we introduce the first application of bacteria nano-formula as a safe environmental approach to control the rice ShB disease, promoting growth and thousand-grain weight in rice.

Effect of Organic Nutrient Management Practices on Growth, Yield and Pests Incidence of Scented Rice (Oryza sativa L.) in Rainfed Situation of Assam

The field experiment was conducted in organic block on experimental farm of AAU-Assam Rice Research Institute, Assam Agricultural University, Titabar, Assam during kharif season of 2019 and 2020 to study the effect of organic nutrient management practices on growth, yield and pests incidence of scented rice (Oryza sativa L.) in rainfed situation of Assam. Eight treatment combinations of organic inputs were laid out in Randomized Block Design with three replications including one control where no organic nutrients were added. The study revealed that combined application of different proportion of green manure, enriched compost, azolla, vermicompost, neem cake with bio fertilizer consortium and rock phosphate as different treatment significantly improved the growth behavior, yield and also reduced pests incidence of scented rice. Among the organic nutrient management treatments, combination of Green manure (2.5 t/ha)+ Vermicompost (2.5 t/ha)+ Biofertilizer consortium (4 kg/ha seedling) as root dip +Rock phosphate (17 kg/ha)+Azolla (20 kg/ha) recorded the highest yield (3.80 t/ha) by improving yield attributing parameters, viz., Panicles (276.3 /m2), Spikelet /panicle (25.50 number) and Panicle weight (3.37g). The organic treatments also significantly enhanced the growth physiology viz., leaf area index (4.32), and specific leaf weight (8.56 mg/cm2) at panicle initiation stage (90 DAT). In organic management treatments, pests and disease incidence significantly reduced compared to control plot. Highest reduction of dead heart (DH%) and white ear head (WEH%) infestation due to stem borer, gall midge (silver shoot) and leaf folder damage was noticed in the treatment combination of Green manure (2.5 t/ha) + Vermicompost ( 2.5 t/ha)+ Biofertilizer consortium (4 kg/ha seedling) as root dip+Rock phosphate (17 kg/ha)+Azolla (20 kg/ha).

Soil water distribution and water productivity in red cabbage crop using superabsorbent polymeric hydrogels under different drip irrigation regimes

The water issue has emerged as a significant barrier to agricultural productivity, particularly in dry and semiarid agro-ecologies, particularly during the winter season. Superabsorbent hydrogels have been identified as effective tools for improving crop and water productivity in arid locations by enhancing moisture retention. The application of hydrogel to soil is commonly done as a basal application, and its effectiveness is heavily influenced by the moisture level present in the soil. Therefore, a two-year field study was carried out to study the effects of various hydrogels and their application techniques and to assess the efficacy of recently developed cross–linked hydrogels (SPG 1118 and Pusa hydrogel) on soil water distribution (both spatial and temporal), water productivity and profitability of red cabbage. The experiment consisted of two irrigation regimes [full irrigation (100% ETc) and limited irrigation (75% ETc)] assisted in main plots, with two type of hydrogels (Pusa Hydrogel and SPG 1118) and two methods of application [root dipping and soil application of hydrogels and Control with no application of hydrogel] assisted in sub plots. The field experiment was conducted using spilt plot design with three replications. The analysis of soil water distribution patterns reveals that the utilization of hydrogels has resulted in a notable increase of 3–6% in soil water content (SWC) under full irrigation conditions, as compared to plots subjected to limited water conditions. In comparison to plots without hydrogel application, the plots treated with SPG 1118 and Pusa hydrogel exhibited enhanced soil water content of 5–6% and 2–4%, respectively. Additionally, the application of hydrogels in the root dipping showed increased water availability in the crop's root zone compared to soil application in throughout the crop season. Thus, hydrogels with reduced irrigation application resulted in significantly higher crop water productivity (14%) and irrigation water productivity (8 – 14%) compared to full irrigation levels. Likewise, root dipping of SPG 1118 led in considerable improvement in CWP (12–14%) and IWP (11–12%) over no hydrogel applied plots. In relation to profitability, the adoption of full irrigation in conjunction with SPG 1118 hydrogel resulted in an 8% increase in the benefit cost ratio compared to the control plots. Hence, the use of the unique SPG 1118 hydrogel through direct application to the roots, whether under conditions of full or limited irrigation, presents an inventive approach to address the growing issues of water shortages and sustainability in countries experiencing water stress.

Effects of organic nutrient management on aromatic rice (Oryza sativa)-linseed (Linum usitatissimum) sequence

The experiment was conducted during 2019 and 2020 at the Instructional-cum Research (ICR) Farm, Assam Agricultural University, Jorhat, Assam to study the impact of different combinations of organic nutrient sources on aromatic rice (Oryza sativa L.) (rainy-kharif) and their residual effect on linseed (Linum usitatissimum L.) (winter- rabi) crop for developing a double cropping sequence for rice growers of Assam with organic management. The experiment comprised three aromatic rice cultivars, viz. Kola joha, Keteki joha and Chakhao poireiton and five combinations of organic nutrient sources. Out of the organic nutrient sources, application of N @30 kg/ha through vermicompost along with pre-season green manuring of Sesbania bispinosa and root dip treatment of rice seedlings with Azospirillium and phosphorus solubilising bacteria @3.5 kg/ha each (N3) resulted the highest number of panicles/ m2 (216.72 in 2019 and 223.96 in 2020), highest yield of rice (30.26 q/ha in 2019, 32.58 q/ha in 2020 grain yield and 65.99 q/ha in 2019, 68.98 q/ha in 2020 straw yield). The highest seed yield (394.52 kg/ha in 2019, 416.97 kg/ha in 2020) and stover yield (890.09 kg/ha in 2019, 896.63 kg/ha in 2020) of succeeding relay sown linseed were recorded with the N3 treatment. The highest available N (250.10 kg/ha), P2O5 (20.40 kg/ha) and K2O (140.06 kg/ha), organic C (0.65%), soil organic carbon (SOC) stock (13.29 t/ha), soil microbial biomass carbon (SMBC) (183.43 µg/g of soil) in soil were recorded with the N3 treatment after harvest of linseed in 2020. The study affirmed the suitability of rice-linseed cropping sequence for efficient utilization and conservation of resources.

Impact of humic acid on various properties of soil and crop productivity- A review

To raise the amount and quality of agricultural produce, numerous studies have been conducted in recent years. The development of agriculture is not just influenced by mechanization and new hybrid seeds; soil quality also plays a significant role. Lack of organic matter in soil frequently renders it unsuitable for plant growth. To address this problem and increase agricultural yields, humic compounds have started to be applied to soil in many parts of the world. Humic acid (HA) can now be applied to crops or soil using a variety of methods, including soil application, foliar application, seed treatment, root dipping, and drip irrigation, as HA is available in various forms viz., granule, powder, flakes, liquid and also in conjunction with inorganic fertilizers. However, soil application is the most effective in numerous studies. Numerous experiments on crops were carried out to determine the ideal dosage of humic acid, and it was found that character, yield, and soil characteristics all had a favourable impact on crop production. This review clarifies the significance of humic acid for various crops and the health of the soil, as well as how it increases agricultural output.

Use of Chemicals and Biological Control Agents as Activators of Plant Defense Against Endoparasitic Sedentary Nematodes.

Full compatible interactions between crop plants and endoparasitic sedentary nematodes (ESNs) lead to severe infestation of the roots and plant growth impairing, as well as to the increase of nematode population in the soil that is a threat for the next planting crop. In the absence of activators, basic plant defense is overcome by nematode secretion of effectorsthat suppress defense gene expression,inhibit ROS generation andtheoxidative burstused byplants to hamper nematode feeding site settlementandlimit its development and reproduction. Activators can be exogenously added as a preventive measure to prime plants and strengthen their defense against ESNs. Activators can be an array of antioxidant compounds or biocontrol agents, such as mutualist microorganisms living in the rhizosphere (biocontrol fungi (BCF), arbuscular mycorrhizal fungi (AMF), plant growth-promoting bacteria (PGPB), etc.). In this chapter, methods are described for usage of both salicylic acid (SA) and its methylated form (Met-SA), and BCF/AMF as elicitors of resistance of vegetable crops against root-knot nematodes (RKNs). The rhizosphere-living BCF/AMF were recovered from commercial formulates pre-incubated in suitable growth media and provided exclusively as soil drench of potted plants. The plant hormones SA and Met-SA were provided to plants as soil drench, foliar spray, and root dip. It is indicated that activators' dosages and plant age are crucial factors in determining the success of a pre-treatment to reduce nematode infection. Therefore, dosages should be expressed as amounts of activators per g of plant weight at treatment. Thresholds exist above which dosages start to work; overdoses were found to be toxic to plants and useless as activators.

Enhancing rice growth and yield with weed endophytic bacteria Alcaligenes faecalis and Metabacillus indicus under reduced chemical fertilization.

Endophytic bacteria, recognized as eco-friendly biofertilizers, have demonstrated the potential to enhance crop growth and yield. While the plant growth-promoting effects of endophytic bacteria have been extensively studied, the impact of weed endophytes remains less explored. In this study, we aimed to isolate endophytic bacteria from native weeds and assess their plant growth-promoting abilities in rice under varying chemical fertilization. The evaluation encompassed measurements of mineral phosphate and potash solubilization, as well as indole-3-acetic acid (IAA) production activity by the selected isolates. Two promising strains, tentatively identified as Alcaligenes faecalis (BTCP01) from Eleusine indica (Goose grass) and Metabacillus indicus (BTDR03) from Cynodon dactylon (Bermuda grass) based on 16S rRNA gene phylogeny, exhibited noteworthy phosphate and potassium solubilization activity, respectively. BTCP01 demonstrated superior phosphate solubilizing activity, while BTDR03 exhibited the highest potassium (K) solubilizing activity. Both isolates synthesized IAA in the presence of L-tryptophan, with the detection of nifH and ipdC genes in their genomes. Application of isolates BTCP01 and BTDR03 through root dipping and spraying at the flowering stage significantly enhanced the agronomic performance of rice variety CV. BRRI dhan29. Notably, combining both strains with 50% of recommended N, P, and K fertilizer doses led to a substantial increase in rice grain yields compared to control plants receiving 100% of recommended doses. Taken together, our results indicate that weed endophytic bacterial strains BTCP01 and BTDR03 hold promise as biofertilizers, potentially reducing the dependency on chemical fertilizers by up to 50%, thereby fostering sustainable rice production.

Selenium Nanoparticles Improves Morpho-Physio-Biochemical Traits and Cadmium Stress Tolerance in Garden Mint using Seedling Root Dip Feeding

Due to extensive global contamination of agricultural soils with cadmium (Cd), there is a dire need for cost-effective and practical methods to ensure the production of safe food. The recent introduction of micronutrients in nano form has been found to reduce the accumulation of Cd in crops. A greenhouse pot-culture experiment was done to investigate the effects of selenium nanoparticles (0, 10, 20 and 30 mgL-1) applied by seedling root dipping technique on the growth, biomass, physio-biochemical and antioxidant potential of mint grown under induced cadmium stress (25 mg kg-1of soil using CdCl2). Findings revealed that application of selenium nanoparticles considerably improved tissues biomass, photosynthesis, and antioxidant enzyme activities in the mint plants. In addition, the application of Se nanoparticles in optimal concentration improved the relative water contents (7.26%), and decreased the electrolyte leakage (32.96%) in plant tissues. Selenium nanoparticles exhibited a dose-additive effect in reducing the levels of malondialdehyde cadmium in tissues of mint plants. Selenium nanoparticles at 20 mg L-1 demonstrated more efficacy than other levels under control and Cd stressed conditions. These findings indicate that seedling root dip feeding of selenium nanoparticles is an efficient approach and could be recommended for remediation of Cd contaminated soils.

Evaluation of antibiotics and bioagents for the management of black rot disease of cabbage and their effect on extracellular polysaccharide secretion

Black rot disease caused by bacterium Xanthomonas campestris pv. campestris has been identified as major cause for low cabbage yields. The present study was conducted to evaluate the efficacy of various antibiotics and bioagents for controlling black rot disease and also their effect on extracellular polysaccharide secretion (EPS) of Xanthomonas campestris pv. campestris. Under in vitro conditions, bacterial proliferation and EPS production were examined on yeast peptone agar medium containing sucrose or trehalose with or without antibiotics. Number of Xanthomonas campestris pv. campestris on yeast peptone agar medium with Validamycin-A was less as compared to control. Extracellular polysaccharide secretion (EPS) was also inhibited on yeast peptone agar medium with antibiotic Validamycin-A. In vivo, disease intensity was recorded minimum in seed treatment + root dipping + foliar spray with Validamycin-A @ 500 µg/ml followed by seed treatment with Validamycin-A @ 500 µg/ml in comparison to control. Similarly, 45.61% higher cabbage yield was recorded in seed treatment + root dipping + foliar spray with Validamycin-A @ 500 as compared to untreated control. However, the antibiotic Validamycin-A which was found effective can be recommended to manage the disease. Bangladesh J. Bot. 52(4): 965-970, 2023 (December)

Effect of nitrogen levels and liquid nano urea application on growth and yield of rice (Oryza sativa L.)

A field experiment was conducted at Pandit Jawaharlal Nehru College of Agriculture and Research Institute, Karaikal to study the effect of nitrogen levels and liquid nano urea application on the growth and yield of rice (Oryza sativa L.) during samba 2021 (September 2021 to January 2022) under puddled transplanted condition, involving fourteen treatments in a randomized block design (RBD) replicated thrice. The experiment involved a combination of four levels of nitrogen (0, 50, 75 and 100 % recommended dose of N) with three methods of liquid nano urea application (seed treatment, root dipping and foliar spraying) along with recommended dose of fertilizers and control. The results revealed that the application of 75 % recommended N + seed treatment with liquid nano urea resulted in the highest values for plant height, leaf area index, leaf area duration, dry matter production and number of tillers hill-1 followed by application of 100 % recommended N + seed treatment with liquid nano urea. Application of 75 % recommended N + seed treatment with liquid nano urea increased the grain yield by 14.8 and 84.3 % and straw yield by 6.5 and 76.4 % over recommended NPK and control, respectively.

Response of Transplanted Rice to Seedling Root-dip in Phosphorus and Biofertilizer Slurry in Acid Soils of North East India- A Participatory Assessment in Farmers’ Field

Background: Rice production is mainly constrained by low P-use efficiency (PUE) and P-recovery efficiency (PRE) in acid soils of the North East hill region of India. Efficient P fertilizer management strategies for rice production is very essential to achieve higher yield per unit of P fertilizer applied. Rhizosphere-based P management in wetland rice is considered as an efficient strategy to minimize the quantity of applied P to obtain a profitable yield. Methods: Seedling root dipping in P slurry technique in farmers’ field condition was studied in comparison to the conventional methods of application of recommended dose of fertilizer (RDF) and the integrated nutrient management (INM) practices to identify a suitable cost effective method of application of phosphatic fertilizer for the acid soils of this hill region of North East India. Result: The highest plant height, maximum number of effective tillers and root biomass were recorded in SSP root dip+Phosphate Solubilizing Bacteria (PSB) followed by INM practices. P root dip had greater root biomass (4.36 g plant-1) which was significantly higher than RDF (3.82 g plant-1). Root dip application showed higher yields (5.80 t ha-1), compared with INM (5.53 t ha-1) and RDF (5.46 t ha-1) and control (4.25 t ha-1). The result of the present study demonstrated that P-dipping can achieve high applied P use efficiency (1193.42) in transplanted rice compared to conventional incorporation of P (625.43). Thus, P-dipping is a potential strategy to overcome low applied P use efficiency in high P-fixing soils and hence reduces the need for excess P application.

Characterization of Fusarium Wilt Disease Among Different Strawberry (Fragaria sp.) Cultivars In Indonesia

Strawberry can be intensively cultivated in small-scale farms without a sequential crop rotation over time. However, to prevent pathogen infection, strawberry requires a continuous pesticide treatment that can harm soil qualities and exacerbate soil-borne pathogen infection. One of the important soil-borne diseases found in strawberries is fusarium wilt. Characterization of symptoms and disease resistance in different cultivars are crucial. This research aims to evaluate the disease resistance level of several strawberry cultivars to the causing pathogen. Eight strawberry cultivars were used in this research, i.e. OSO Grande, SC Pujon, EBI 13, Korea, Local Batu, Chandler, BK and RB AOI. These cultivars were inoculated with the pathogen to assess level of the disease resistance by root dip inoculation method. In this research, Fusarium oxysporum is found to be the main cause of crown rot and wilting in these cultivars. The disease intensities were not significantly different among cultivars. The highest and lowest intensities of the infected crown were recorded in the Korea and BK cultivars with 50% and 16.7% respectively, although there are differences in percentage of crown infected. Similarly, the crown root diameter is not significantly different among cultivars. On the other hand, the trichome size of these cultivars appeared to be affected by the pathogen infection, shown by the size reduction in the infected cultivars.

Preventive and Curative Effects of Treatments to Manage Strawberry Root and Crown Rot Caused by Neopestalotiopsis rosae.

Strawberry root and crown rot caused by the fungus Neopestalotiopsis rosae is an emerging disease that has caused yield losses of up to 70% in Mexico and other regions worldwide. This research evaluated the effects of biological and chemical fungicides applied as preventive and curative applications for controlling root and crown rot caused by N. rosae in strawberries under greenhouse conditions. Treatments included these chemical fungicides: prochloraz, prochloraz + thiram, cyprodinil + fludioxonil, difenoconazole + azoxystrobin, iprodione, captan, thiram, pydiflumetofen + fludioxonil, fluxapyroxad + pyraclostrobin, and hymexazol; each was applied at commercial doses. Also tested were biological treatments based on Trichoderma koningiopsis, T. asperellum, Streptomyces sp., and Bacillus amyloliquefaciens strain D747 (B. velezensis). Disease incidence, severity, plant mortality, root length, and dry weight were determined. Results showed that overall, preventive applications of the fungicides pydiflumetofen + fludioxonil, cyprodinil + fludioxonil, and prochloraz resulted in the smallest area under the disease progress curve and the lowest final disease incidence, severity, and plant mortality. An intermediate group of effective treatments entailed hymexazol, iprodione, T. asperellum, and T. koningiopsis (50 to 75% efficacy). Treatments with greater efficacy (99 to 100%), pydiflumetofen + fludioxonil, cyprodinil + fludioxonil, and prochloraz, also had maximal total plant biomass vis-à-vis the untreated control. By contrast, each treatment's efficacy was significantly reduced when applied curatively (0 to 37% treatment efficacy). These results suggest that certain treatments are useful for controlling strawberry root and crown rot caused by N. rosae when applied preventively (as root dipping). These results will contribute to designing more effective management programs for root and crown rot caused by N. rosae on strawberry.

Integrated management practices against an emerging Bakanae disease of rice under the hot-humid climate of Indo-Gangetic plains of India

Bakanae disease caused by Fusarium fujikuroi is emerging in India. In this work, fungicides and biocontrol agents were evaluated as seed, seedling treatment, and foliar spray(s) against bakanae disease in rice under field conditions. Carbendazim (50% WP) was found to be the most effective fungicide for seed and seedling root dip treatments. Soil drenching with 0.25% carbendazim (50% WP) 5 days before transplanting of seedlings was effective for large scale treatments. Foliar spray of 0.1% tebuconazole 50%+ trifloxystrobin 25% w/w (75 WG) significantly reduced the percentage of infected seeds (7.17%) compared with the control (32.50%). The minimum disease incidence (31%) was observed when seeds were treated with Talaromyces flavus. Individual treatments were integrated in the form of six management modules and evaluated under the field conditions of New Delhi (India) and Pusa Bihar (India) with the susceptible cultivars ‘Pusa Basmati 1121’ and ‘Pusa 1176’. Bakanae disease incidence was lower in the modules tested compared with the inoculated control or the individual treatment. The most favorable results at two locations achieved the lowest disease incidence of 7% and 2.41%.

Sources of genetic resistance to Fusarium wilt (Fusarium oxysporum f. sp tracheiphilum) in cowpea (Vigna unguiculata (L.) Walp.) and comparison of inoculum concentration levels

Fusarium wilt caused by Fusarium oxysporum f. sp tracheiphilum (Fot) is a soil-borne fungal disease of significant constraint to cowpea production in West Africa. The disease infection can cause up to 100% yield loss in highly infested fields. The most effective control strategy is the use of resistant varieties. Sixty cowpea germplasm collections were screened for resistance to F. oxysporum. The result revealed that only two (TVu 134 and TVu 410) of the germplasm showed a high level of resistance when subjected to artificial epiphytotic and innovative seedling root dip screening methods using three inoculum concentration levels. These two cultivars can be used directly by farmers or as potential donors for developing resistant cultivars against F. oxysporum. The study also identified useful polymorphic SSR markers associated with resistant and susceptible parents, which will significantly enhance the breeding programs in developing varieties’ resistance to the disease.