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Sarao P.S.,Punjab Agricultural University | Sahi G.K.,Punjab Agricultural University | Neelam K.,Punjab Agricultural University | Mangat G.S.,Punjab Agricultural University | And 2 more authors.
Rice Science | Year: 2016

Out of 1 989 wild accessions sown in seed boxes for screening, only 1 003 wild accessions with good germination were screened against brown planthopper (BPH), Nilaparvata lugens (Stål) under greenhouse conditions. The collection comprised of accessions from 11 wild species and African cultivated rice. The germplasm was screened for BPH following standard seed box screening technique in the greenhouse. As many as 159 accessions were identified as resistant during the year 2012 based on one year screening. A selected set of BPH resistant accessions were screened again during 2013. Based on the two years screening, seven accessions of O. nivara (AA), one accession of O. officinalis (CC), seven accessions of O. australiensis (EE), five accessions of O. punctata (BB and BBCC) and nine accessions of O. latifolia (CCDD) were confirmed to be resistant to BPH. So far no BPH resistance genes have been identified and designated from O. nivara and O. punctata, hence these may act as new sources of resistance. © 2016 China National Rice Research Institute.

Molla K.A.,University of Calcutta | Molla K.A.,ICAR National Rice Research Institute | Karmakar S.,University of Calcutta | Chanda P.K.,University of Calcutta | And 5 more authors.
Plant Science | Year: 2016

Rice sheath blight disease, caused by the fungus Rhizoctonia solani, is considered the second most important disease of rice after blast. NPR1 (non expressor of PR1) is the central regulator of systemic acquired resistance (SAR) conferring broad spectrum resistance to various pathogens. Previous reports have indicated that constitutive expression of the Arabidopsis thaliana NPR1 (AtNPR1) gene results in disease resistance in rice but has a negative impact on growth and agronomic traits. Here, we report that green tissue-specific expression of AtNPR1 in rice confers resistance to the sheath blight pathogen, with no concomitant abnormalities in plant growth and yield parameters. Elevated levels of NPR1 activated the defence pathway in the transgenic plants by inducing expression of endogenous genes such as PR1b, RC24, and PR10A. Enhanced sheath blight resistance of the transgenic plants was evaluated using three different bioassay systems. A partially isolated toxin from R. solani was used in the bioassays to measure the resistance level. Studies of the phenotype and yield showed that the transgenic plants did not exhibit any kind of phenotypic imbalances. Our results demonstrate that green tissue-specific expression of AtNPR1 is an effective strategy for controlling the sheath blight pathogen. The present work in rice can be extended to other crop plants severely damaged by the pathogen. © 2016 Elsevier Ireland Ltd.

Gangopadhyay K.K.,ICAR National Bureau of Plant Genetic Resources | Singh A.,ICAR National Bureau of Plant Genetic Resources | Bag M.K.,ICAR National Rice Research Institute | Ranjan P.,Indian Institute of Vegetable Research | And 3 more authors.
Genetic Resources and Crop Evolution | Year: 2016

The wild species in general is considered to be the reservoir of genes especially for biotic and abiotic stresses. In okra, the predominant biotic stresses are yellow vein mosaic disease (YVMD), shoot and fruit borer and leaf hopper. Sixty eight (68) accessions belonging to four wild Abelmoschus species [Abelmoschus caillei (A. Chev.) Stevels, Abelmoschus manihot (L.) Medik., Abelmoschus moschatus (L.) Medik. and Abelmoschus tuberculatus Pal et Singh] and eight okra varieties were characterized and evaluated for phenological characters including biotic stresses under natural epiphytotic condition. The wild species examined consisted of 18 accessions (16 exotic and 2 indigenous) of A. caillei, 29 accessions of A. manihot, 16 accessions of A. moschatus and 5 accessions of A. tuberculatus. All the wild Abelmoschus species exhibited high diversity (as measured by Shannon Diversity Index) for 3 qualitative characters viz. intensity of stem colour, leaf shape, epicalyx shape, 13 quantitative characters and 3 biotic stress parameters. Among the wild species, A. caillei and A. tuberculatus showed maximum and minimum diversity for qualitative characters, respectively. There was significant variation for 19 out of 24 quantitative characters studied. Inter-species diversity pattern as estimated through Ward’s Minimum Variance Dendrogram and Principal Component Analysis revealed clear differentiation among the species with minimum overlapping indicating close association between geographical origins and clustering pattern. Intra-species diversity indicated role of specific adaptation in sub-clustering. Resistance to YVMD was found in accessions belonging to three wild species viz. A. caillei, A. manihot and A. moschatus while resistance to shoot and fruit borer and leaf hopper was found in accessions of all the four wild species. The resistant accessions can further be used for introgressing biotic stress resistance through pre-breeding into cultivated okra species. © 2016 Springer Science+Business Media Dordrecht

Saha S.,ICAR National Rice Research Institute | Munda S.,ICAR National Rice Research Institute | Adak T.,ICAR National Rice Research Institute
Indian Journal of Agricultural Sciences | Year: 2016

A field experiment was conducted during the wet seasons of 2010 and 2011 at ICAR-National Rice Research Institute, Cuttack to study the efficacy of azimsulfuron for controlling broad spectrum of weeds in transplanted rice (Oryza sativa L.) field under rainfed shallow lowland. The present study consisted of 10 treatments which includes seven doses of azimsulfuron, viz. 12.5, 17.5, 22.5, 27.5, 30.0, 35.0 and 40 g/ha each with 0.2% surfactant along with recommended herbicide, pretilachlor at 625 g/ha, weed-free and weedy as check. Yield attributes of rice were significantly (P<0.05) affected by weed control treatments. The highest grain yield (5.72 tonnes/ha) and N-use efficiency (57.2) were obtained in weed free check, realizing 76% increase in grain yield of rice over weedy check. Azimsulfuron at 35 and 40 g/ha applied 18 days after transplanting was found to be very effective (weed control efficiency 92.8 and 95.5%, respectively) in controlling the complex weed flora and produced comparable grain yield with weed-free check. There was more than 45% reduction in the grain yield of rice due to competition with weeds in weedy plots. The negative effect of weed competition in weedy check plot was reflected in significant reduction in crop growth rate (4.66 g/m2/day) and total biomass of rice (6.89 tonnes/ha).

Tripathi R.,ICAR National Rice Research Institute | Shukla A.K.,P.C. | Shahid M.,ICAR National Rice Research Institute | Nayak D.,ICAR National Rice Research Institute | And 10 more authors.
Ecological Engineering | Year: 2016

In this paper an attempt has been made to quantify and test whether rice cultivation in adjoining areas of mangrove forest by cutting forest tress has brought about significant changes in physicochemical, microbial and enzymatic properties of soils of the mangrove ecosystem. We collected 48 soil samples (24 pairs). We collected paired soil samples from each location, i.e., one soil sample from mangrove forest and its paired soil sample from adjacent rice fields. Various soil physicochemical, microbial and enzymatic properties were analyzed. Total soil organic carbon (TOC), available potassium and Bray P were significantly higher in soils of mangrove forest than soils of cultivated rice fields. Soil pH was in the acidic range at all locations, but was moderated towards neutral in mangrove soils. DTPA extractable concentrations of soil micronutrients (Zn, Mn) were significantly higher under the soils of mangrove than soils under cultivated rice fields. Enzymatic activities (Dehydrogenase, Urease, FDA hydrolysis, Acid Phosphatase) in soils of mangrove forests exceeded than under cultivated rice fields except for acid phosphatase activity which had higher activity in soils of cultivated rice fields. Populations of ammonium oxidizer and nitrite oxidizer were higher in mangrove soils, whereas populations of aerobic hetreotrophs were higher in cultivated rice fields compared to mangrove soils. The study provides a soil quality index based on soil physico-chemical and microbiological properties. This index is a function of the eight soil parameters, which showed the greatest weight in the factorial analysis made with all the parameters analysed. The value of the soil quality index was higher in mangrove soils compared to soils of rice fields at all the four locations of sampling indicating the adverse effect of rice cultivation around the mangrove forests. © 2016 Elsevier B.V..

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