Bio-priming Of Seeds Research Articles

Management of Wilt Complex of Chickpea with Seed Biopriming and Soil Application of Trichoderma spp.

Background: Chickpea wilt complex caused by several soil-borne pathogens is a serious biotic constraint for chickpea production.Methods: To find out the effective management of the disease through seed biopriming and soil application of biocontrol agents under in vivo and in vitro conditions experiments were carried out during rabi 2018-19 and 2019-20 at Anand Agricultural University, Anand, Gujarat.Result: Seed biopriming showed a positive impact producing vigorous plant shoot and root system, besides disease control during in vitro conditions. While under in vivo conditions, the pooled results of two years revealed that seed biopriming for 10 h with the suspension of talc-based formulation (2 x 108 CFU/g) of Trichoderma viride or T. asperellum @ 50 g in 250 ml of water/kg of seed followed by soil application of T. viride or T. asperellum enriched FYM (10g/kg FYM) @ 100 g/m2 of soil found significant for the disease management as well as higher yield. The seed biopriming alone control the disease in the range of 23-34% and increased the yield of chickpea by 23-29%. However, combined applications of seed biopriming as well as soil application significantly control the disease in the range of 51-70% and increased the grain yield by 41-51% over untreated control.

Effect of Integration of Seed Bio-priming and Inorganic Fertilization on Soil Physico-chemical Properties of Sunflower (Helianthus annuus L.)

Conventional agricultural practices rely on the immense application of agrochemicals that show detrimental effects on soil biota. Negative impacts on soil microbiota and enzymes that involve in nutrient cycles hinder nutrient availability. Application of plant growth-promoting microbes such as Trichoderma spp. can evade these hurdles by improving soil biodiversity and performance of the crop. A pot culture experiment was conducted during two consecutive years (2018 and 2019) to figure out the effect of different doses of fertilizers and seed bio-priming with Trichoderma asperellum BHUT8 in sunflower (PAC-334) on soil chemical properties. Results showed that the initial soil reaction was slightly alkaline that tend towards neutral with seed bio-priming. The electrical conductivity of soil in both seasons varied randomly among imposed treatments. Soil cation exchange capacity, which permits the soil to hold all essential nutrients, was enhanced 4% with the supply of 70% recommended dose of fertilizer and seed bio-priming. Soil available nitrogen, phosphorus, and potassium were found maximum in the treatments supplied with Trichoderma through seed bio-priming. Inoculation of Trichoderma showed positive effects on soil chemical properties and reduced the requirement of inorganic fertilizers.

Biopolymers for biopriming of Brassica rapa seeds: A study on coating efficacy, bioagent viability and seed germination

The coating agent is critical in ensuring the success of seed biopriming. In this study, various biopolymers (sodium alginate, carboxymethylcellulose, gum arabic, xanthan gum) were tested for their efficacy as a coating agent for bioagent (Trichoderma asperellum) bioprimed to Brassica rapa (pak choy) seeds. Seeds and bioagent were first treated separately in biopolymer solutions, and examined for seed germination and spore viability, respectively, as a measure of compatibility. The suitable biopolymers and concentrations were then used to coat T. asperellum to the seeds, and the percentage of spore entrapped, and viable spore count were determined to reflect coating efficacy. The biopolymer with efficient coating efficacy was selected and employed as coating agent with various spore concentrations on seeds, and seed germination and radicle length were determined. Results revealed that coating with biopolymers benefited seeds. Spore viability was higher when treated with all biopolymers (89–100%) than without (84%). Higher coating efficacy was achieved with sodium alginate (1.5% w:v) which entrapped more spores during biopriming (83.63 ± 0.86%) and retained more viable spores (4.01 ± 0.01 log spore seed-1) after 24 h post-priming. Biopolymers have no adverse effect on radicle length and seed germination, although increasing spore concentrations inhibited radicle elongation. In short, biopriming using sodium alginate (1.5% w:v) with 102 spores/mL of T. asperellum is therefore recommended for Brassica seeds as higher seed germination (90.67 ± 2.88%) and overall benefits can be achieved.

Biopriming of seeds with plant growth promoting bacteria Pseudomonas fluorescens for better germination and seedling vigour of the East Indian sandalwood

The East Indian sandalwood (Santalum album L), one among the valued timber species in the global market due to its sweet-scented heartwood, is facing a drastic decline of its natural populations over the past three decades. The major constraint in the regeneration of sandal is the slow, staggered, and poor germination of the seeds. The germination may continue even up to one year. The present investigation focused on the impact of biopriming on the germination and seedling performance in sandal. Fresh mature seeds of sandal were procured from the Nachivayal Reserve Forest, Marayur Sandal Division. The seeds were subjected to 16 biopriming treatments using Pseudomonas fluorescens at 4 concentrations (25, 50, 75 and 100%) and 4 durations (2, 4, 6, and 8 days). The results revealed that the biopriming at 100% for 8 days recorded the highest germination percentage (88%) within 21 days with lowest energy period (15 days) and highest germination energy (62.98%). Biopriming at 50% concentration for 8 days was the next best treatment which improved the germination of sandal seeds and the lowest germination percentage was recorded in control seeds (46%). With regard to the seedling growth, the biopriming treatment contributed a significant increase in growth attributes of the seedlings. We recommend the biopriming with Pseudomonas fluorescens at 100% for 8 days as a potential technique to enhance seed germination and seedling growth in sandal.

Effect of different sources of organic manures and seed bio-priming on yield and economics of Rice bean (Vigna umbellate)

A field experiment was conducted during kharif-2019 at Research Institute of Organic Farming field unit, UAS, GKVK, Bengaluru to study the Effect of different sources of organic manure and seed bio-priming on growth and yield of rice bean (Vigna umbellate) laid out in Factorial Randomized Complete Block Design with 10 treatments replicated thrice and the variety used was KBR-1. Results of the experiment revealed that seed bio priming with Rhizobium and Trichoderma recorded significantly higher seed yield (1184.87 kg ha-1) and stover yield (3052.56 kg ha-1), yield attributes like number of pods per plant (59.87), pod length (8.69 cm) seed yield per plant (11.37 g) and 100% N equivalent through vermicompost resulted in significantly higher seed yield (1789.50 kg ha-1) and stover yield (3504.47 kg ha-1), yield attributes like number of pods per plant (69.67), pod length (9.92 cm), number of seeds per pod (9.17) seed yield per plant (12.83 g). Lower seed yield (237.3 kg ha-1) and stover yield (1985.2 kg ha-1) recorded T1 (without seed bio-priming). Whereas, higher B:C ratio (2.96) was recorded with 100% N equivalent through neemcake + seed bio-priming.

Biopriming of sweet pepper and tomato seeds with Ascophyllum nodosum

Organic agriculture has been growing in recent years; however, one of the limitations in this area is the treatment of seeds with natural products and less aggressive to the environment. Seed biopriming with brown seaweed extract can be used to improve the physiological quality of seeds. This study aimed to evaluate the effect of seed biopriming with Ascophyllum nodosum extracts (algae) on pepper and tomato seed quality. Pepper seeds of All Big and Alegria cultivars (cvs), and tomato seeds of Cereja and Rio Grande cvs were used. The extract concentrations were 0, 125, 250, and 375 ppm. A completely randomized design in a 2×4 factorial scheme was used. The variables analyzed were percentage germination; germination speed index; root and shoot length; and root and shoot dry weight. Sweet pepper biopriming at 125 ppm enhanced germination in 16.5% for All Big cv; but it did not benefit Alegria cv. A. nodosum as a biopriming provided an increase of 50% in root length growth in Alegria cv; although, it had a negative effect on the growth of pepper seedlings of the All Big cv at 375 ppm. Tomato seed biopriming with A. nodosum at 125 ppm, enhanced root and shoot growth by 38 and 31% of Cereja cv; Nevertheless, it did not provide higher levels of germination. For Rio Grande cv, shoot growth was benefited at 125 ppm, with approximately 1.04 cm larger than the control. The effect of Ascophyllum nodosum priming depended on its concentration and the cultivar given that, different responses were obtained, also due to the compounds of the extract.

Response of Black Gram to Seed Biopriming with Facultative Halophilic Bacteria under Salinity

Under high salinity conditions, plant growth promoting halophilic bacteria (PGPHB) can thrive and greatly encourage plant growth. The use of PGPHB is minimal and less discussed in sustainable agriculture and abiotic stress control. The focus of the current investigation is to improve the growth of black gram by inoculating with of halophilic bacteria under salinity stress. Four PGPHB bacteria, viz., Bacillus safensis strain Lewis_Bac_3 (HB-5), Pseudomonas stutzeri strain MN1 (HB-13), Staphylococcus xylosus strain C5 (HB-18) and Pseudomonas sp. (GP-21: reference strain) were inoculated to black gram seeds to evaluate their plant growth promoting ability at 4 dS m-1 and pH >8.5. Increase in root length, plant height, and number of branches have been reported in consortium treatment (T8), indicating that salinity does not affected black gram photosynthesis and nutrient absorption in consortium treatment. Corroborating evidence revealed higher nodulation and total nitrogen and phosphorous content in the same treatment, in comparison with control. Due to salinity stress, decreased blooming was reported in control, conversely, consortium treatment showed 29.3 flowers/plant. A positive correlation with yield was demonstrated by number of pods and seeds per pod of black gram. In addition, there is a strong association between pods per plant and the amount of flowers per plant, nutrient content, and length of root. The decrease in control plot yield was due to shoot and root development resulting from insufficient nutrients availability. In this study we also found positive correlation between% P in plant and yield. Hence, we conclude that PGPH bacteria helps in the reduction of salt stress and significantly increase black gram growth and yield under mild salinity stress.

Seed bio-priming with tri-species consortia of phosphate solubilizing rhizobacteria (PSR) and its effect on plant growth promotion

Three potential rhizobacteria namely Burkholderia gladioli (MTCC 10216), Pseudomonas sp. (MTCC 9002) and Bacillus subtilis (MTCC 8528) procured from IMTECH, Chandigarh (India) were evaluated individually and as consortia for its phosphate (P) solubilizing ability and effect of growth of fenugreek (Trigonella foenum-graecum L.) and tomato (Lycopersicon esculentum L.). Phosphate solubilizing ability of these strains individually and as consortia was tested on Pikovskayas agar medium, Phosphate solubilizing agar medium and National Botanical Research Institute phosphate agar medium containing six different sources of insoluble inorganic phosphate such as tri-calcium phosphate (TCP), di-calcium phosphate (DCP), zinc phosphate (ZP), ferric phosphate (FP), sodium di-hydrogen phosphate (SP), and aluminum phosphate (AP), and two organic P such as calcium and sodium phytate. The maximum P solubilizing ability was recorded in consortium-4 having all three potential bacterial strains. Phosphate solubilization after 7th day of incubation was 37.9 mg/100 ml of TCP, 40.01 mg/100 ml of DCP, 15.79 mg/100 ml of FP, 43.02 mg/100 ml of SP, no solubilization of ZP and AP, 39.75 mg/100 ml of calcium phytate and 24.01mg/100 ml of sodium phytate. Seed germination and the other plant parameters such as plant height and weight significantly increased in fenugreek and tomato seeds, bio-primed with consortium-4 followed by consortium-3. After bio-priming of seeds in pot assay, the level of phosphorus in soil got increased by 54% in consortium-4 treated soil followed by consortium-3 (47%) over untreated control soil. Based on these findings, consoritium-4 could be recommended as a good bio-inoculant for fenugreek, tomato and other crops in comparison to individual strains and other consortia.

Influence of Seed Biopriming and Vermiwash Treatment on Tomato Plant's Immunity and Nutritional Quality upon Sclerotium rolfsii Challenge Inoculation

Tomato is an important nutritional vegetable crop and its nutrient contents are affected by both biotic and abiotic stresses. The main objective of this study was to determine the effect of seed biopriming with Trichoderma pseudokoningii BHUR2 and vermiwash treatment on nutrient content of tomato and defense response against Sclerotium rolfsii under heat stress condition. The combined application of T. pseudokoningii BHUR2 and vermiwash increased fresh weight of root (4.8-fold) and shoot (5.8-fold), dry weight of root (6.9-fold) and shoot (6.4-fold) and number of fruits per plant (4.2-fold) as compared to control under S. rolfsii inoculated condition. Plants treated with T. pseudokoningii BHUR2 and vermiwash exhibited higher defense response against S. rolfsii, mediated by higher activity of superoxide dismutase (3.57-fold), peroxidase (2.05-fold) and phenylalanine ammonia lyase (2.98-fold) enzymes and accumulation of total phenol content (5.35-fold) as compared to control plants. In addition, combined treatment was found to have a positive impact on nutritional status (N, P, K and Ca and lycopene, total soluble sugar and total protein) in tomato fruit. These results suggest potential of T. pseudokoningii BHUR2 and vermiwash in enhancing tomato immunity against S. rolfsii under heat stress condition, which was due to (1) induction in the antioxidant activity and phenylpropanoid pathway, which minimize oxidative damage and reduce pathogen infection and (2) significant improvement in nutrient content leads to better plant growth. The formulation of Trichoderma BHUR2 can be used for field application to mitigate heat stress in plants.

Influence of Seed Biopriming with Microbial Inoculants on Seed Quality Parameters in Soybean [Glycine max (L.) Merril

The present investigation was carried out in the Department of Seed Science and Technology, College of Forestry, Ranichauri, Tehri Garhwal, Uttarakhand during 2015. A laboratory experiment was conducted to find out the influence of bio-priming on seed germination and seedling vigour. Seed germination was reported maximum for Psf-173 (93.66%) while minimum was reported for control (65.66%). Seed vigour parameter viz. root length (11.01 cm), shoot length (7.96 cm), seedling length (18.98 cm), fresh weight (8.00 g) and dry weight (1.31 g), vigour index I (1666.80) and vigour index II (115.56) was found higher for PSB treatment. Shilajeet variety had recorded significant higher values for most of the germination and vigour parameters. Shilajeet bio-primed with PSB attained higher values for majority of the quality parameters. Under laboratory condition results suggested that seed germination and seed vigour were greatly affected by different bio-agents. Among all the bio-agents, PSB showed positive influence on most of the quality parameter. However, other bio-agents had also showed significant effect over control.

Seed biopriming with antagonistic microbes and ascorbic acid induce resistance in tomato against Fusarium wilt

Seed biopriming is an emerging technique to enhance seed germination under stress conditions. An integrated approach of tomato seed biopriming with ascorbic acid, Trichoderma asperellum BHU P-1 and Ochrobactrum sp. BHU PB-1 was applied to observe the response against wilt pathogen of tomato Fusarium oxysporum f. sp. lycopersici (FOL). Tomato seeds bioprimed with the aforementioned application expressed augmented seed germination and activated of defense response. Seed germination was recorded higher (80 %) at low concentration (1 pM) of ascorbic acid as compared to high concentration of 1 mM (41 %). Combination of both ascorbic acid and antagonistic microbe treatments (T5 & T6) significantly reduced disease incidence (up to 28 %) in tomato plants at 10 days. T5 and T6 treated plants exhibited higher accumulation of total phenol content and increased activity of Phenylammonia lyase (PAL), Peroxidase (PO), Chitinase (Chi) and Polyphenol oxidase (PPO) as compared to control (T1) plants. ROS formation in the form of H2O2 was also found to be reduced in combined treatment. Histochemical analysis revealed that phenylpropanoid pathway (lignin deposition) was more activated in combined priming treatment plants as compared to individual treatment upon challenge inoculation with FOL. Transcript expression analysis of defense genes confirmed the up-regulation of PAL (2.1 fold), Chi (0.92 fold), Pathogenesis related proteins (PR) (1.58 fold) and Lipoxygenase (Lox) (0.72 fold) in T6 treatment as compared to T1 treatment plants at 96 h. This study reveals that ascorbic acid treatment with antagonistic microbes through seed priming effectively induced seed germination and elicited defense mechanism to control wilt disease in tomato plants.

Influence of seed priming on the development of pearl millet downy mildew (Sclerospora graminicola)

Pearl millet is a major cereal and fodder crop and prone to attack by Sclerospora graminicola causing downy mildew. The effect of priming for the control of downy mildew using biocontrol agents viz. Trichoderma viride, Pseudomonas fluorescens and Bacillus subtilis and two aqueous plant extracts Melia azedarach and Azadirachta indica was evaluated in two consecutive Kharif seasons in 2016 and 2017. Treatments consisted of seeds bio-primed with P. fluorescens, B. subtilis and T. viride; hydro-primed with plant extracts; chemo-primed with fungicide (mancozeb 64% + metalaxyl 4%) and control as hydro-primed and non-primed seeds. Priming of seeds with biocontrol agents resulted in improved seed germination and vigorous root and shoot growth of pearl millet in vitro. Maximum seed germination and seedling vigour index was provided by seeds primed with M. azedarach extract (93.14% and 1659.48). Bio-priming of seeds with B. subtilis and its foliar application was found most effectual treatment for controlling downy mildew.

Effect of TNAU-Pf1 seed biopriming and foliar spray of newer fungicides on the incidence of leaf blight of sunflower

Seed biopriming followed by foliar spray of different newer fungicide molecules to manage sunflower leaf spot under field conditions have been tried in Coimbatore, Tamil Nadu, India for three consecutive years (2014-2016). The result indicated that among the different treatments tested, seed biopriming with TNAU Pseudomonas fluorescens (Pf1) @ 10g/kg seeds followed by spray of Hexaconazole @ 0.1% at 45 days and P. fluorescens (Pf1) @ 1.0% at 60 DAS showed less severity of Alternaria leaf spot (25.7) with the highest yield of 1471kg/ha against the control (47.7) which recorded yield of 1111kg/ha. In addition, seed biopriming promoted higher and uniform seed germination under field conditions.

Bioprospecting Drought Tolerant <i>Trichoderma harzianum</i> Isolates Promote Growth and Delay the Onset of Drought Responses in Wheat (<i>Triticum aestivum</i> L.)

The objectives of this study were to investigate whether seed biopriming through drought tolerant isolates of Trichoderma harzianum induces drought tolerance in wheat. Physiological and biochemical parameters were also monitored under greenhouse conditions to explore the mechanism underlying plant water stress resilience in response to Trichoderma inoculation.The impact of bioprospecting Trichoderma harzianum drought tolerant isolates, Rani Th-14, Rani Th-21, Rani Th-25, Rani Th-30 and Rani Th-39 on wheat response to drought was studied. Measurements of the stomatal conductance, net photosynthesis, chlorophyll fluorescence and greenness of plants were performed. In addition, analysis of the total phenolic compounds, free proline, MSI (membrane stability index) as well as lipid peroxidation was carried out. With or without exposure to drought conditions, colonization by Trichoderma isolates promoted seedling growth, the most consistent effect being an increase in shoot and root growth. The primary direct effect of colonization was promotion of root growth, regardless of water status, and an increase in water content, which it is proposed, caused a delay in many aspects of the drought response of wheat. Colonization of Trichoderma by seed biopriming enhanced drought tolerance of wheat plants as they delayed drought induced changes like stomatal conductance, net photosynthesis, chlorophyll fluorescence and greenness of plants. Drought stress from 4 to 13 d of withholding water induced an increase in the concentration of many stress induced metabolites in wheat leaves, while Trichoderma colonization caused a decrease in proline, MDA and H 2 O 2 contents and an increase in phenolics concentration. Among different Trichoderma isolates, Rani Th-14 induced maximum drought tolerance as treated plants recorded only 20-40 per cent wilting even at 13 days drought stress (DDS). The study is important as the experiments confirmed that the drought tolerant isolates of Trichoderma through seed bio priming are critical in inducing tolerance to drought.

Seed bio-priming withTrichoderma asperellumeffectively modulate plant growth promotion in pea

Seed biopriming is an advance technique of seed treatment that involves application of beneficial microorganism on seed surface followed by seed hydration. Seed bioprimig is a ecological to control the many seed and soil-borne pathogens which provide an alternative to chemical treatment. Seed biopriming enhance the initial step of plant development by increased seed germination and provide protection before seedling emergence. Trichoderma spp. is widely used for biocontrol agent that enhance plant growth as well as inhibits phytopathogen. In the present study, effectiveness of biopriming with T. asperellum BHUT8 evaluated for plant growth promotion effect in pea. The results showed enhancement in plant growth in the treated plants as compared to control. There was increase in shoot length, root length, number of leaves, shoot fresh weight, root fresh weight, shoot dry weight and root dry weight by 35.29, 96.49, 28.13, 36.10, 146.26, 30.17 and 77.20%, respectively, as compared to the control.

Role of Pellets and Capsules of Acacia nilotica and Sapindus mukorossi in Combination of Seed Bio-Priming with Microbial Antagonists in the Supression of Root Infecting Pathogenic Fungi and Promotion of Crop Plants

Present research investigate the effect of Acacia nilotica and Sapindus mukorossi pellets (pyrophyllite mixed with leaves powder @ 50:50 ratio), capsules (empty shells of capsules filled with leaves powder @ 0.5 g) alone or in combination with bio-priming of leguminous and non-leguminous seeds with microbial antagonists like Trichoderma harzianum and Rhizoboium melilotii. It was found that A. nilotica, S. mukorossi pellets and capsules in combination with biopriming of seeds with T. harzianum were most effective for the promotion of growth and reduction of root infecting fungal pathogens like Macrophomina phaseolina, Rhizoctonia solani and Fusarium sp on peanut, chickpea, okra and sunflower.

Biological Management of Damping-Off, Buckeye Rot and Fusarial Wilt of Tomato (cv. Solan Lalima) under Mid-Hill Conditions of Himachal Pradesh

Disease management is often complicated by the presence of multiple types of pathogens; in an organic system, it is appropriate to develop disease control strategies. The available literature so far reflects that the management of important disease of tomato is through the integrated approaches and very few organic approaches have been tried with various degree of success. Boiopriming of seeds with biocontrol agents (Trichoderma viridae, Trichoderma harzianum and Pseudomonas fluorescens) in combination with different biofertilizers (Azotobacter, Azospirillum and PSB) and organic manures (FYM and vermi-compost) were tested against disease incidence and health management of tomato seedling under nursery as well as field conditions. The studies were conducted during two successive years (2012-2013) at farmer’s field with the objective to combat with the increasing disease incidence of three major disease damping-off, fusarium wilt and buckeye rot from nursery stage to the final harvesting. The study focused on the use of biocontrol agents as the suitable alternative to chemical pesticides with sustainable disease management without pesticide residues in foodstuff. The bio priming of seeds with fungal antagonist Trichoderma viridae and harzianum and bacterial antagonist Pseudomonas fluorescens significantly improved the germination behavior of tomato seeds as compared to untreated control. Highest mean germination (93.1%) and seedling vigour (953.33) was recorded in Treatment 3 (FYM @ 200 q/ ha + Azospirillum + PSB + Trichoderma herzianum (4 kg/ha each) and lowest in control (60.3%) and (304.83), thus indicating a significant per cent increase in seedling emergence (54.4%) and seedling vigour (95.23%). A considerable reduction in disease incidence (pre and post) of damping off was observed in treatment T? and T? (VC @ 50 q/ha + Azospirillum + PSB + Trichoderma herzianum @ (4 kg/ha) with 45.6% and 35.4% respectively). Treatment T? proved highest in terms of yield (665 Kg/Ha), Hence these diseases can be managed by successful application of Biocontrol agents.

Role of Different Additives on Survival of Serratia plymuthica HRO-C48 on Oilseed Rape Seeds and Control of Phoma lingam

For optimum inhibition of plant pathogens, biocontrol agents must be maintained at higher density and survive for a long time in the plant system. Biopriming of seeds with bacteria in the presence of different additives provide a promising technique that might improve the efficacy of biocontrol agents and their application. The aim of this work was to test different additives and stickers on the activity of Serratia plymuthica in oilseed rape in controlling Phoma lingam. Seeds were soaked in bacterial suspensions (log10 11 CFU ml) containing one of the following Stickers and additives in a ratio of 1:1:1 (w:v:v): Sodium alginate, Dextran T 40, Polyvinyl alcohol, Methylcellulose, Gum Arabic, Raffinose, Tween 20, and Paraffin oil. Seeds were stored either at room temperature or at 4°C. Number of bacteria inside the seeds was monitored over a period of 12 months. The effect of additives and stickers on bacterial efficacy in controlling Phoma lingam was evaluated in pot experiments. Number of bacterial cells inside the seeds was significantly higher in the seeds coated with GA+MgSO4, RF+MC and PA (log10 7.5 ± 0.2, log10 7.5 ± 0.2 and log10 Original Research Article British Microbiology Research Journal, 4(7): 737-748, 2014 738 7.4 ± 0.4, respectively). Interestingly, bacterial concentration in seeds stored at 4°C was higher than that in seeds stored at 20°C. Moreover, after storage for 8 months, Serratia plymuthica was able to control the black leg disease. Our results showed that some additives and stickers prolonged the shelf life of bacteria inside the seeds and improved the efficacy of bacteria in controlling the disease.

Bio-priming of seeds: A potential tool in the integrated management of alternaria blight of sunflower

Of the different integrated seed treatment options tested for the management of Alternaria blight of sunflower, highest benefit was obtained in the seed treatment with Carbendazim+Iprodione (Quintal) at 0.3% in water along with hexaconazole foliar spray (0.1%) followed by seed treatment with Pseudomonas fluorescens (0.8%) in jelly+hexaconazole foliar spray. Efficacy of Pseudomonas fluorescens as seed dresser can be enhanced by bio-priming the sunflower seeds for the effective and eco-friendly management of Alternaria blight of sunflower.

Development of Formulations ofPseudomonas fluorescensfor Control of Chickpea Wilt

Pseudomonas fluorescens strains were obtained from the rhizosphere of different crops and strains that showed inhibitory action against the chickpea (Cicer arietinum) wilt pathogen Fusarium oxysporum f. sp. ciceris were selected for further studies. The efficacy of various carriers in sustaining the population of these strains in storage was assessed. In talc-based and peat-based formulations the bacteria survived even up to 240 days of storage although the population declined from 30 days. When chickpea seeds were treated with talc-based formulations, P. fluorescens survived on the seeds for at least 180 days. When the treated seeds were sown in soil, the antagonist moved to the rhizosphere and survived well in it. Biopriming of seeds increased rhizosphere population. Seed treatment with the antagonist formulation effectively controlled chickpea wilt disease in the two field trials and increased the yield. When seed treatment was followed by root zone application the efficacy of P. fluorescens formulations increased. Pseudomonas fluorescens did not inhibit the beneficial N-fixing bacteria Rhizobium and Azospirillum in vitro and seed treatment fungicides (thiram and carbendazim) were not inhibitory to P. fluorescens in vitro.