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Background: Sclerotium rolfsii Sacc. is one of the destructive soil-borne plant pathogens due to its significant loss in terms of yield and quality in several crop plants including soybean. Use of biocontrol agents in the management of disease is an ecofriendly strategy. Therefore, the study aimed to assess in vitro antagonisticactivity of rhizobacteria and endophytes against Sclerotium rolfsii following dual culture technique. Methods: A total of 75 rhizobacterial isolates, 3 endophytes along with reference cultures were evaluated for the antagonistic activity against Sclerotium rolfsii following dual culture technique. The effective rhizobacterial isolates were tested for the various plat growth promoting rhizobacteria traits viz., indole acetic acid production, siderophore production, phosphate solubilization, production of ammonia, hydrogen cyanide production and chitinase test following the standard procedure. Result: The two promising rhizobacterial strains i.e., AUUB 209 (Streptomyces enissocaesilis) and Streptomyces racemochromogenes (AUDT 626) were found effective with 76.79 and 64.75 per cent mycelial inhibition of Sclerotium rolfsii under in vitro. The antagonistic activity of these two rhizobacteria is mainly attributed to the positive confirmation of various PGPR activities viz., production of Indole acetic acid, siderophore, phosphate solubilization and chitinase production. [ABSTRACT FROM AUTHOR]

Background: Groundnut is the principal vegetable oil crop in India and about 85 per cent groundnut area under remains rain fed. Stem rot of groundnut is more prevalent in the area and is capable of causing considerable loss in the yield when left unmanaged. Methods: In order to find out an effective method of managing the disease, an integrated approach was adopted by combining the use of bio agents, organic amendments and fungicides alone and in combinations. Result: Seed treatment with tebuconazole @ 1 g kg-1 and with commercial formulation of Trichoderma harzianum @ 5g kg-1 seed along with soil application of neem cake @ 1.3 t ha-1 maintained its superiority over other treatments by recording the least PDI, maximum germination percentage (98.20%), root length (14.62 cm), shoot length (35.54 cm), number of pods per plant (32.57) and pod yield (3920.0 kg ha-1) which may be synergistic effect of organic amendment with bioagent. However, all the sole treatments also managed the disease to some extent but greater control was recorded in combination treatments than alone. [ABSTRACT FROM AUTHOR]

Background: Sclerotium rolfsii is a soil borne notorious pathogen widely affecting pulses, vegetables, oil seeds, flowers and ornamentals recording high yield loss. In groundnut it causes stem rot. The current study is focused towards management of S. rolfsii using combined application of Trichoderma spp. under field condition. Methods: Twenty-five isolates of Trichoderma spp. were screened initially against the stem rot pathogen through dual culture method. The effective Trichoderma spp. again assessed by agar well diffusion method and their secondary metabolites were identified using GC-MS. Result: From the 25 isolates, T. longibrachiatum and T. asperellum were inhibitory to the growth of S. rolfsii. The isolate T(SP)-20 of T. longibrachiatum showed 84.44% inhibition of mycelial growth of pathogen followed by T(AR)-10 of T. asperellum (75.55%). The major compounds present in GC-MS analysis of T. longibrachiatum and T. asperellum are 2-Tricosenoic acid (3.29%), Hexadecane (3.12%) and Phenol (27.18%), 2,6,10-Trimethyltridecane (3.44%) respectively. At field level combined application of effective T. longibrachiatum and T. asperellum excelled well in reducing stem rot disease incidence (82.67%) when compared to individual species. [ABSTRACT FROM AUTHOR]

Sclerotium rolfsii is a soil borne fast spreading fungal pathogen that causes collar rot in chickpea. The variability among the pathogen isolates have made difficult to design efficient management practices and necessitates for a comprehensive study to know its diversity. The present study was planned to study the genetic diversity among the isolates of S. rolfsii collected from chickpea growing regions of Kurnool and Ananthapur districts of Andhra Pradesh at morphological and molecular level. The morphological characterization of isolates on PDA indicated that the isolates, CSR 14, CSR 18 and CSR 20, were fast growing and the overall growth i.e., sclerotia formation in terms of number, size and days to formation, was also faster. These isolates took only 4 days for production of sclerotial bodies. A total of 254 reproducible and scorable polymorphic bands ranging from 200 to 2000 bp were observed with twenty nine RAPD primers. The RAPD banding pattern reflected the presence of greater variability among the isolates and grouped the isolates into two clusters. The isolates, CSR 18 and 20, formed the cluster II revealing their distantness from other isolates at molecular level. The isolate, CSR 14, formed a separate sub cluster in the cluster I indicating its distant association with other isolates of this cluster. [ABSTRACT FROM AUTHOR]

An experiment was conducted to evaluate the effect of palm kernel cake fermentation (PKCF) with Sclerotium roflsii by adding humic acid as broiler diet on the performance of broiler. Two hundred DOC of broiler were used in this experiment and randomly assigned to five treatments (0%, 17%, 22%, 27%, 32% palm kernel cake fermented in diets) in a completely randomized design (CRD) with four replications. The diets were formulated in iso protein 22% and iso caloric 3000 kcal/kg ration. The parameters of this study were feed consumption, body weight gain, feed conversion, body weight, carcass percentage of broiler. The result of this study showed that feed consumption, body weight gained, feed conversion, body weight, carcass percentage were not significantly affected (P>0.05) by any treatment. In conclusion the palm kernel cake fermented (PKCF) by Sclerotium roflsii can be used up to 32% in broiler diets. [ABSTRACT FROM AUTHOR]

Stem rot (Sclerotium rolfsii Sacc.) resistance in groundnut genotypes was due to activities of defense enzymes such as, catalase, peroxidase and polyphenol oxidase. Bio-agent, Bacillus amyloliquefaciens isolated from groundnut rhizosphere enhances the activities of defense enzymes through salicylic acid induced systemic resistance. In resistant genotypes (NRCGCS-19 and NRCGCS-319) higher activities of defense enzymes were recorded constitutively while in susceptible genotypes it was increased after bio-agent treatment. The activities of pathogenesis related-proteins viz., polygalacturonase and chitinase were registered in plants inoculated with S. rolfsii. Enzymes, catalase, peroxidase, polyphenol oxidase and chitinase showed strong negative correlation with disease severity index. However, the activity of polygalacturonase was directly related to disease severity index and inversely related to activity of chitinase. Hence, to obtain required levels of crop protection against S. rolfsii one has to grow either resistant genotypes or bio-agent treated susceptible genotypes. [ABSTRACT FROM AUTHOR]

Plant growth-promoting rhizobacteria (PGPR) thrive in the rhizosphere of plants and play a beneficial role in plant growth, and development along with biocontrol activities. The present study was undertaken with the aim of developing rhizobacterial inoculants for groundnut for enhancement of growth and yield and suppression of major soil-borne fungal diseases caused by Sclerotium rolfsii (stem rot) and Aspergillus niger (collar rot). Out of a total of 154 rhizobacterial isolates obtained from groundnut rhizosphere, 78 isolates were selected on the basis of in vitro antifungal activities against three major soil-borne fungal pathogens of groundnut, i.e. Aspergillus niger, Aspergillus flavus and Sclerotium rolfsii. The selected isolates were further screened for the production of 2,4-Diacetylphloroglucinol (2,4-DAPG) by the gene specific PCR amplification of phlD gene. A total of 11 rhizobacterial isolates were found to have DAPG-producing genes and selected for further studies. Gene specific primers were also used for characterization of the isolates for plant growth-promoting and biocontrol traits. The qualitative and quantitative estimation of the various attributes of the isolates were also carried out. Majority of the isolates showed production of IAA, siderophores and fluorescent pigments. The DAPG-producing rhizobacterial isolates have great potential as bio-inoculants for groundnut crop for suppressing soil-borne fungal pathogens and to enhance growth and yield. [ABSTRACT FROM AUTHOR]

The experiments were conducted during 2009 and 2010 to find out the most effective screening techniques for identifying host plant resistance against chickpea collar rot caused by Sclerotim rolfsii in pot house. Out of four techniques employed, chickpea 'grain inoculation techniques' was found best. The minimum post emergence mortality (6.7%) occurred at 4.0 percent concentration of Pyraclostrobin which is significantly relatively less in comparison to control (26.8%) during the two consecutive year of testing. Among 88 chickpea desi genotype GNG 1958 was found resistant to disease whereas , 13 entries viz., NDG 9-21, PG 97030, BG 3004, JG 14-11, H 04-68, PG 054, BGD 1058, GJG 0724, RSG 931, JG1307, GJG 0504, JG 14-110, H05-24 were moderately resistant. Among Kabuli types, two entries i.e GNG 1969, BG 2086 were resistant and 9 as moderately resistant (IPCK 2005-23, Phule G 0027, JGK 2003-304, IPCK 02, BG 3001, MNK 1, BG 3000,Vihar, HK 06-168). [ABSTRACT FROM AUTHOR]