Journal of Applied and Natural Science
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Potential of Inula racemosa root extract and its fractions to suppress root-knot nematode Meloidogyne incognita
Get PDFNematicidal potential of chloroform root extract of Inula racemosa and its fractions was investigated on egg hatching and mortality of root knot nematode Meloidogyne incognita. Egg masses and second stage juveniles (J2) of M. incognita were exposed to different concentrations (0.1-8.0 mg ml-1) of I. racemosa root extract and its fractions. Observations on egg hatch were recorded on 1st, 3rd, 5th, 7th and 9th day and those of mortality studies were recorded on 2nd, 4th, 6th, 8th and 10th day, respectively. Significant mortality as well as egg hatch inhibition was observed for all the tested components at 5 %. The root extract was found to be most effective in controlling egg hatching as complete inhibition was observed at 8.0 mg ml-1 concentration on 1stday of treatment and nonpolar fraction was most effective in causing mortality of J2 of M. incognita as 100 % inhibition was observed at 6.0 and 8.0 mg ml-1 concentration on 2nd day of treatment. Maximum inhibition of egg hatching was observed for root extract at 8.0 mg ml-1 concentration and 100 % mortality was observed for root extract as well as nonpolar fraction at the same concentration. The nonpolar fraction was most effective in causing mortality as maximum mortality was observed at 6.0 and 8.0 mg ml-1 concentration throughout the exposure time. Polar fraction was least effective among all the components both in egg hatch inhibition and J2 mortality of M. incognita. Both the activities showed concentrations as well as time dependence. Results show different role of tested components on egg hatching and mortality of root knot nematode. The root extract of I. racemosa and its fractions showed a potential to develop new nematicide
Effect of arbuscular mycorrhizal (AM) fungi inoculation on enzymatic activity and zinc uptake under direct seeded rice system
Get PDFThe application of treatment T3 (Glomus mosseae + 100 % RDF NK) produced significantly more root volume by 72.60 %, 17.80 %, 12.25 %, 14.13 % over the application of treatment T1 (Control), treatment T5 (Glomus coronatum+ 100 % RDF NK), T6 (Gigasporadecipein + 100 % RDF NK) and T7 (BAU AM-1(Glomus sp + 100 % RDF NK), respectively. Similar trend shows at harvesting stage, here the maximum root volume (23c.c) was recorded by the application of T3 (Glomus mosseae + 100 % RDF NK). Maximum AM colonization and spore count was observed at panicle initiation stage with the application of treatment T3 (Glomus mosseae + 100 % RDF NK). This treatment also gave maximum dehydrogenase activity (55.86 µg TPF g-1 24 hr-1), acid phosphatase activity (0.299 mg PNP g-1 hr-1) and alkaline phosphatase activity (0.54 mg PNP g-1 hr-1) at panicle initiation stage. Application of treatment T3 (Glomus mosseae + 100 % RDF NK) significantly increased DTPA extractable Zn in soil and Zn content in plant when compared with all the treatments except treatment T6 (Gigasporadecipien+ 100 % RDF NK). The maximum zinc uptake (0.056 mg pot-1) by grain was recorded under treatment T3 (Glomus mosseae + 100 % RDF NK) followed by application of treatment T6 (Gigasporadecipien + 100 % N and K). Highest grain yield (14.08 g pot-1) was found with the treatment T3 (Glomus mosseae + 100 % RDF NK). As evident from the results, the AM fungal inoculation can effectively modify the soil microbe population and community structure by increasing the soil enzymatic activities and significantly increased the zinc uptake by grain in direct seeded rice (DSR)
Dynamics of Sclerotium rolfsii as influenced by different crop rhizosphere and microbial community
Get PDFThis study was carried out with the aim of evaluating pathogenicity of Sclerotium rolfsii to different crops influenced by different crop rhizosphere microbes and their population dynamics. Napier was found to be non-preferred host against S. rolfsii pathogen. Among the seven tested crops in micro-plot study, highest level of induction of sclerotial population was observed in groundnut and cow peas (21.81 and 20.06 numbers of sclerotia /100 g of soil, respectively), whereas, reduction in sclerotial number was observed in napier, maize and sorghum plots. S. rolfsii induced damping off was found to be significantly positively correlated with average sclerotial population irrespective of plant cover even at 1% level of significance (r = 0.985) and among the microbiological parameters, FDA was found to be significantly negatively correlated with damping off disease percentage at 5% level of significance (r = - 0.830). Therefore, Napier may be the potential crop to be incorporated in the sequence of rice/vegetable based cropping system in West Bengal for management of this dreaded pathogen
Spatial distribution of Brevicoryne brassicae (L.) in Cabbage in mid-hills of Himachal Pradesh, India
Get PDFInvestigations were carried out during two consecutive Rabi seasons of 2014 and2015 at the Experi-mental Farm of the Department of Seed Science and Technology, Dr Y S Parmar University of Horticulture and For-estry, Nauni, Solan, Himachal Pradesh, India to study the spatial distribution of Brevicoryne brassicae in cabbage. One month old cabbage seedlings were planted in the field in the month of November during both the years. Distri-bution pattern of any insect population is an important aspect as it represents the interaction between individuals of the species and their habitat. Spatial distribution is useful for designing efficient sampling programmes for population estimation and development of population models. Spatial distribution is also important to understand the bioecology of the pest and to determine the sampling protocol for that species. In the present study variance to mean ratio (s2/X),mean crowding (X*), ratio of mean crowding to mean (X*/X), ‘k’ of negative binomial, Taylor’s power equation(s2 = 0.9099X1.55 during 2014 and s2 = 2.9861X1.1949 during 2015), Iwao’s patchiness regression and optimum number of samples (Nopt) required to achieve the desired precision were calculated for different densities. Cabbage aphid, B. brassicae appeared in the fourth standard week i.e last week of January( 26.2 aphids/ plant during 2014 and 0.30 aphids/ plant during 2015) and persisted upto thirteenth standard week i.e last week of April ( 18.4 aphids/ plant during 2014 and 18.2 aphids/ plant during 2015) and followed a negative binomial distribution during both years. Optimum number of samples (Nopt) required varied with mean density as well as precision level. The present study will serve as basic information to develop a sampling plan of B. Brassicae in cabbage for its monitoring and management
RNA interference- a novel approach for plant disease management
Get PDFRNA interference (RNAi) is an incredible revolution in the field of functional genomics, a breakthrough in plant molecular genetics. This technology will generate enormous potential for engineering control of gene expres-sion. The success of managing biotic stress using RNAi technology will prove to be biologically and environmentally safe. It is therapeutic in approach as the resistance induced by RNAi is triggered by ds RNA that results in silencing of specific genes before being translated in a homology dependent manner. Over the time, RNAi is significantly proving it as one of the most promiscent management strategy which eliminates certain risks associated with the development of transgenic plants. This review gives an insight into the probability of management of plant diseases caused by various biotic agents viz. fungi, bacteria and viruses using RNA interference technique and host-pathogen related targeted sites
Rhizosphere competence of native Rhizobium rhizogenes strain and its use in management of crown gall
Get PDFNative Rhizobium rhizogenes strain UHFBA-212 [141/1A (NCBI: KC488174)]was isolated from rhizosphere soil of peach nursery plant of wild peach collected from Himachal Pradesh. In addition to this,159 isolates were also collected and were screened in vitro for their biocontrol potential against Agrobacterium tumefaciens. Out of these strain, UHFBA-212 showed maximum zone of inhibition i.e. 4.16 and 3.57cm without and after exposure to chloroform against C58.Sequence analysis (16SrDNA) of the strain showed nucleotide homology similar to Rhizobium sp. Amplification of total genomic DNA of the strain with Vir D2 andipt primers didn’t showed amplification with these virulence genes suggesting the absence of tumorigenic factors. In the field conditions, maximum population (329.33x106 cfu/g of soil) was observed in antibiotic resistant mutant of R. rhizogenes strain K84 applied on cherry rootstock Colt followed by 285.33 (x 106 ) cfu/g of soil in UHFBA-212 after 9 months at the time of uprooting of plants when applied alone as root dip. Minimum incidence of crown gall (2.00%) was observed in strain UHFBA- 212 co inoculated with strain C58 as seed treatment on behmi seeds. The data on population indices in rhizosphere and incidence of crown gall further suggested that for better management of disease R. Rhizogenes isolates should be either equal or more in population than that of A. tumefaciens isolates. Strain UHFBA-212 controls crown gall as effectively as strain K84 and can be exploited against tumorigenic isolates under field conditions
Screening for pod shattering in mutant population of mungbean (Vigna radiata (L.) Wilczek)
Get PDFMungbean, (Vigna radiata (L.) Wilczek) occupies a unique position in Indian agriculture and has been grown under various agro-ecological conditions. It is cultivated in 1.61mha with production of 3.38MT and productivi-ty of 474kg/ha in India. Mungbean pods are thin and brittle when dry, so shattering is a major problem. The loss of seeds by pod dehiscence is one of the major reasons for low yield in mungbean; thus, reducing the frequency of pod dehiscence is an important objective in mungbean breeding. Induced mutations, have offered a single and short alternative to conventional breeding including isolation, screening, selection and testing generation after generation. In this study, variability was induced by gamma rays and Ethyl methane sulphonate (EMS) in two greengram geno-types viz., CO (Gg) 7 and NM 65. Screening for pod shattering was carried out in M2 and M3 populations of green-gram. The scoring for shattering was recorded at physiological maturity of the pod. The shattering percentage ranged from 14.56 (400 Gy) to 93.45 per cent (20 mM). A total of 100 shattering tolerant mutants were selected from field based on visual observation. These mutants were again scored under laboratory condition as per IITA method. A total of 12 mutants of CO (Gg) 7 and 10 mutants of NM 65 which were tolerant to pod shattering were identified in M2 generation and forwarded to M3 generation. These mutants were scored for pod shattering under laboratory con-dition and nine mutants viz., M26, M44, M46, M58, M70, M71, M84, M92 and M98 were found to be tolerant in M3 generation. This study on identification and screening of the mutants tolerant to pod shattering with high yielding potential will help to increase the production of the pods to a greater extent
Hydropriming -a useful technique for seed invigoration in okra (Abelmoschus esculentus) and parsley (Petroselinum crispum)
Get PDFSeed germinating ability and stand establishment determine the management options in crop production system. Physiological advancement of seeds through priming is a simple and cost-effective method to improve the germinability and stand of any crop. Studies were performed on seed invigoration through hydropriming at the division of PHT, SKUAST-Kashmir during the year 2016 to optimize the hydropriming duration for improved germi-nation and seedling vigour of okra (Pusa sawani) and parsley (curly type). Freshly harvested seeds were soaked in normal water for varying durations (okra- 12, 18 and 24 h; parsley- 24, 48 and 72 h) at (25±2°C) and re-dried to original moisture content at room temperature. Fifty seeds of each treatment were cultured in 14.0 cm Petri dishes lined with 5 layers of moist blotting paper. Observations on various germination parameters were recorded at (25±2°C). Priming of okra seeds for 18 h resulted in highest FGP (85.7%), GE (66.5%), GI (36.7), SDB (29.1mg) and SVI (2.49) coupled with minimum values of T50 (2.75 day) as well as MGT (2.38 day). However, the highest FGP (78.7%), GE (48.7%), SDB (3.13 mg), GI (12.8) and SVI (0.25) together with minimum T50 (7.2 day) and MGT (6.5 day) in parsley was recorded with 24 h priming duration. As such priming duration of 18 and 24 hours at 25±2°C were found optimal for enhanced and rapid seed germination with vigourous seedlings
Effect of long - term integrated nutrient management on crop yield, nutrition and soil fertility under rice-wheat system
Get PDFLong-term effect of nitrogen substitution (25 to 50%) through different organics, viz., FYM (farm yard ma-nure), GM (green manure) and WS (wheat straw) on crop yield, nutrition and physico-chemical properties of soil was studied under rice-wheat system. The data of long term experiment revealed that maximum grain yield of 46.83 qha-1 in wheat was obtained when 100% RDF applied through mineral fertilizers after 50% N of RDF being substituted with FYM in rice. Grain yield of wheat declined under control and sub-optimal fertilizer inputs (50% or 75% recommended fertilizer NPK), whereas positive yield increment was observed under treatments receiving organic supplements. The analysis of soil samples showed that soil pH reduced from initial value of 7.40 to 7.22, organic carbon build-up from 0.46% to 0.76%, available N from 194.00 to 225.95 kgha-1 available P2O5 from 23.60 to 49.54 kgha-1 and available K2O from 155.00 to 189.95 kgha-1 However, available Sulphur and DTPA-Zn increased from 7.74 to 14.41 kg ha-1 and 0.75 to 1.37 mg kg-1 respectively due to long-term (29 years) integrated nutrient management practices under rice-wheat system in alluvial soil. In conclusion, substitution of 50% and 25% N of RDF to rice through organics either FYM / Green manure / Wheat straw significantly increased the crop yield and nutrient uptake of wheat as well as build up the organic carbon, available N, P2O5, K2O, Sulphur, DTPA extractable Zn, Cu, Fe and Mn of post harvest soil after 29 years of the experiment
Integrated management of late blight of potato
Get PDFLate blight of potato is the major biotic constraint responsible for reduction in yield and quality of the pota-to crop. Globally, late blight is managed through application of multiple fungicidal chemical sprays affecting both human health and environment. Now a days, methods of biological control are gaining importance as these are non-toxic and also environment friendly. However, Phytophthora infestans multiplies very fast; therefore, biological con-trol method alone is not a viable option to manage late blight. Hence, integration of both methods is essential. Eleven treatments consisting of biocontrol agents and fungicides were evaluated against the late bight in three consecu-tive seasons (2011-12, 2012-13, 2013-14) at ICAR-CPRIC, Modipuram. Meerut. The results revealed that the treat-ments ( T1 to T10) are effective for managing the disease up to certain level; however, lowest average disease se-verity (27.89%) was recorded in treatment when Bacillus subtilis (B5-0.25%) + Trichoderma viride (TV-0.7%) was applied before disease appearance followed by cymoxanil8+mancozeb 64%WP (0.3%) at onset of late blight and one more spray of B5+ TV after seven days. The next best treatment was application of B5+ TV before appearance of disease followed by metalaxyl 8+mancozeb 64%WP (0.25%) at onset of late blight and one more spray of B5+ TV against control (average disease severity 91.94%) with higher yield also except the treatment of three spray of mancozeb 75% WP (0.2%). These treatments could be integrated in farmer practices