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Gajbhiye A.,Rashtrasant Tukadoji Maharaj Nagpur University | Rai A.R.,Rashtrasant Tukadoji Maharaj Nagpur University | Meshram S.U.,Rashtrasant Tukadoji Maharaj Nagpur University | Dongre A.B.,Central Institute for Cotton Research
World Journal of Microbiology and Biotechnology | Year: 2010

Present investigation is based on the isolation of Bacillus subtilis from cotton rhizosphere and their evaluation as biocontrol agent against Fusarium oxysporum. The production of extracellular hydrolytic enzyme was studied for determining the antagonism. 43% of 21 isolates were identified under the B. subtilis group on the basis of biochemical characterization. 38% isolates showed competitive activity against Fusarium oxysporum and exhibit more than 50% mycelial inhibition in dual culture bioassay. The pot assay of cotton by seed treatment and soil amendment technique under green house condition showed the competent activity of the isolates in preventing the wilting of cotton seedlings due to F. oxysporum infection. SVI values of 30day old seedlings indicated that the soil inoculation with B. subtilis BP-2 and seed treatment with B. subtilis BP-9 significantly promoted the growth of cotton seedlings. RAPD profiling revealed the diversity in the Bacillussubtilis group, ranging from 10 to 32%. The discriminative pattern among the isolates belonging to the same species was validated by 16S rDNA partial sequencing which identified them into four different strains of B. subtilis. © Springer Science+Business Media B.V. 2009. Source


Prabhakar M.,Indian Central Research Institute for Dryland Agriculture | Prasad Y.G.,Indian Central Research Institute for Dryland Agriculture | Thirupathi M.,Indian Central Research Institute for Dryland Agriculture | Sreedevi G.,Indian Central Research Institute for Dryland Agriculture | And 2 more authors.
Computers and Electronics in Agriculture | Year: 2011

Detection of crop stress is one of the major applications of hyperspectral remote sensing in agriculture. Many studies have demonstrated the capability of remote sensing techniques for detection of nutrient stress on cotton with only few on pest damage but none so far on leafhopper (LH) severity. Subsequent to introduction of Bt cotton, leafhopper is emerging as a key pest in several countries. In view of its wide host range, geographical distribution and damage potential, a study was initiated to characterise leafhopper stress on cotton, identify sensitive bands, and derive hyperspectral vegetation indices specific to this pest. Cotton plants with varying levels of LH severity were selected from three locations across major cotton growing regions of India. About 57-58 cotton plants from each location exhibiting different levels of LH damage symptoms were selected. Reflectance measurements in the spectral range of 350-2500nm were made using hyperspectral radiometer. Simultaneously chlorophyll (Chl) and relative water content (RWC) were also estimated from the selected plants. Reflectance from healthy and leafhopper infested plants showed a significant difference in VIS and NIR regions. Decrease in Chl a pigment was more significant than Chl b in the infested plants and the ratio of Chl a/b showed a decreasing trend with increase in LH severity. Regression analysis revealed a significant linear relation between LH severity and Chl (R2=0.505**), and a similar fit was also observed for RWC (R2=0.402**). Plotting linear intensity curves between reflectance at each waveband with infestation grade resulted in six sensitive bands that exhibited maximum correlation at different regions of the electromagnetic spectrum (376, 496, 691, 761, 1124 and 1457nm). Regression analysis of several ratio indices formulated with two or more of these sensitive bands led to the identification of new leaf hopper indices (LHI) with a potential to detect leafhopper severity. These new indices along with 20 other stress related hyperspectral indices compiled from literature were further tested for their ability to detect LH severity. Two novel indices LHI 2 and LHI 4 proposed in this study showed significantly high coefficients of determination across locations (R2 range 0.521 to 0.825**) and hence have the potential use for detection of leafhopper severity in cotton. © 2011 Elsevier B.V. Source


Trushina N.,Technion - Israel Institute of Technology | Levin M.,Technion - Israel Institute of Technology | Mukherjee P.K.,Bhabha Atomic Research Center | Mukherjee P.K.,Central Institute for Cotton Research | Horwitz B.A.,Technion - Israel Institute of Technology
BMC Genomics | Year: 2013

Background: In fungi, environmental pH is an important signal for development, and successful host colonization depends on homeostasis. Surprisingly, little is known regarding the role of pH in fungal-fungal interactions. Species of Trichoderma grow as soil saprobes but many are primarily mycotrophic, using other fungi as hosts. Therefore, Trichoderma spp. are studied for their potential in biocontrol of plant diseases. Particularly in alkaline soil, pH is a critical limiting factor for these biofungicides, whose optimal growth pH is 4-6. Gaining an understanding of pH adaptability is an important step in broadening the activity spectrum of these economically important fungi. Results: We studied the pH-responsive transcription factor PacC by gene knockout and by introduction of a constitutively active allele (pacCc). ΔpacC mutants exhibited reduced growth at alkaline pH, while pacCc strains grew poorly at acidic pH. In plate confrontation assays ΔpacC mutants showed decreased ability to compete with the plant pathogens Rhizoctonia solani and Sclerotium rolfsii. The pacCc strain exhibited an overgrowth of R. solani that was comparable to the wild type, but was unable to overgrow S. rolfsii. To identify genes whose expression is dependent on pH and pacC, we designed oligonucleotide microarrays from the transcript models of the T. virens genome, and compared the transcriptomes of wild type and mutant cultures exposed to high or low pH. Transcript levels from several functional classes were dependent on pacC, on pH, or on both. Furthermore, the expression of a set of pacC-dependent genes was increased in the constitutively-active pacCc strain, and was pH-independent in some, but not all cases. Conclusions: PacC is important for biocontrol-related antagonism of other fungi by T. virens. As much as 5% of the transcriptome is pH-dependent, and of these genes, some 25% depend on pacC. Secondary metabolite biosynthesis and ion transport are among the relevant gene classes. We suggest that ΔpacC mutants may have lost their full biocontrol potential due to their inability to adapt to alkaline pH, to perceive ambient pH, or both. The results raise the novel possibility of genetically manipulating Trichoderma in order to improve adaptability and biocontrol at alkaline pH. © 2013 Trushina et al.; licensee BioMed Central Ltd. Source


Rathinavel K.,Central Institute for Cotton Research
Indian Journal of Agricultural Research | Year: 2015

Experiments conducted to elucidate the impact of polymer coating on viability of cotton seeds at Central Institute for Cotton Research, Regional Station, Coimbatore, India revealed that seeds coated with polymer "polycote" or " polyloc" @ 3 ml kg-1 + thiram @ 2.5 g kg-1+ super red @ 5 ml kg-1 + cruiser @ 5 g kg-1 packed in polythene bag (700 gauge ) and stored at ambient condition for 26 months was found superior in preserving seed quality viz., seed viability expressed in terms of germination and seedling vigour over untreated seeds. The percentage loss of viability was less rapid and at 26th month of storage it was 70% where as in control 56%. Less seed infection, high seedling vigour and field emergence was recorded in coated seeds. Source


Behere G.T.,University of Melbourne | Behere G.T.,Indian Council of Agricultural Research | Tay W.T.,CSIRO | Russell D.A.,University of Melbourne | And 2 more authors.
PLoS ONE | Year: 2013

Helicoverpa armigera is an important pest of cotton and other agricultural crops in the Old World. Its wide host range, high mobility and fecundity, and the ability to adapt and develop resistance against all common groups of insecticides used for its management have exacerbated its pest status. An understanding of the population genetic structure in H. armigera under Indian agricultural conditions will help ascertain gene flow patterns across different agricultural zones. This study inferred the population genetic structure of Indian H. armigera using five Exon-Primed Intron-Crossing (EPIC)-PCR markers. Nested alternative EPIC markers detected moderate null allele frequencies (4.3% to 9.4%) in loci used to infer population genetic structure but the apparently genome-wide heterozygote deficit suggests in-breeding or a Wahlund effect rather than a null allele effect. Population genetic analysis of the 26 populations suggested significant genetic differentiation within India but especially in cotton-feeding populations in the 2006-07 cropping season. In contrast, overall pair-wise FST estimates from populations feeding on food crops indicated no significant population substructure irrespective of cropping seasons. A Baysian cluster analysis was used to assign the genetic make-up of individuals to likely membership of population clusters. Some evidence was found for four major clusters with individuals in two populations from cotton in one year (from two populations in northern India) showing especially high homogeneity. Taken as a whole, this study found evidence of population substructure at host crop, temporal and spatial levels in Indian H. armigera, without, however, a clear biological rationale for these structures being evident. © 2013 Behere et al. Source

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