Kumar U.,ICAR National Rice Research Institute |
Panneerselvam P.,ICAR National Rice Research Institute |
Govindasamy V.,Indian Agricultural Research Institute |
Vithalkumar L.,Indian Agricultural Research Institute |
And 3 more authors.
Ecological Engineering | Year: 2017
Diazotrophs are one of the most important microbial communities which play a key role in rhizosphere to enhance plant growth-promotion by supplying fixed nitrogen to the plants. The aim of present study was to analyze the frequency and diversity of diazotrophs in the rhizospheres of five genotypes of aromatic rice (Oryza sativa cultivars Nua Kalajeera, Ketekijoha, Nua Desheri, Nua Chandan and Kala Namak) grown in ten years old long-term aromatic rice-rice (LARR) cropping system under sub-humid tropical condition. In this study, it was observed that very less frequency of active diazotrophs (0–14.28%) in the rhizosphere of aromatic rice genotypes based on polymerase chain reaction (PCR)-based nifH gene amplification, dot blot hybridization and acetylene reduction assay (ARA). The following five isolates (B10, B12, B29, BK16, NKR16) from rhizosphere of aromatic rice and the reference strain Azospirillum brasilence showed nifH amplification and positive signal for dot blot. None of these isolates showed positive in ARA test except A. brasilence. Basic local alighnment search tool (BLAST) homology of nifH sequences of B10, B12, B29, BK16 and NKR16 matched with Gluconoacetobacter diazotrophicus, Pseudomonas stutzeri, Klebsiella sp., Klebsiella pneumoniae and Sinorhizobium meliloti, respectively. Whereas, isolates B10, B12 and BK16 were identified as Bacillus cereus, Enterobacter sp., and Lysinibacillus sp., respectively based on 16S-rDNA sequencing. As per nifH sequences, these diazotrophs (B10, B12, B29, BK16, NKR16) fall under α and γ-proteobacter, whereas 16S-rDNA sequences revealed that they belonged to firmicutes and γ-proteobacter. Multiple sequence alignment of nifH gene sequences showed wider variation among diazotrophs, however 3D structure of NifH protein revealed the less diversity among isolates. Moreover, restriction digestion of 16S-rDNA using tetracutters (MspI, MboI and HaeIII) deciphered a unique pattern among small population of diazotrophs.The results of this finding provided an interesting data and novel information of diazotroph diversity in LARR cropping system. Finally, the present study indicated that the continuous application of high dose of inorganic nitrogenous fertilizers (nitrogen at the rate of 60 & 80 kg N ha−1 year−1 in wet and dry seasons, respectively) limit the frequency and diversity of rhizospheric diazotrophs in the LARR cropping system. © 2017 Elsevier B.V.
SINGH T.,Regional Rainfed Lowland Rice Research Station |
SATAPATHY B.S.,Regional Rainfed Lowland Rice Research Station |
GAUTAM P.,ICAR National Rice Research Institute |
LAL B.,ICAR National Rice Research Institute |
And 3 more authors.
Experimental Agriculture | Year: 2017
Weed management is the major challenge to the success of boro rice (rice grown during Dec–Jan to May–Jun, also known as summer rice) in Southern Asia. Herbicide seems to be a cost effective and strategic tool from an agronomic view point to control weeds; however, herbicide application can potentially interfere with soil enzyme activity and microbial biomass carbon (MBC). A field study was conducted in 2012/13 and 2013/14 to evaluate the performance of sole and combined application of different pre-emergence herbicides in comparison to manual weeding in boro rice. Lowest weed density, biomass and highest weed control efficiency (~83%) were recorded with the pyrazosulfuron ethyl, causing higher grain yield (6.7 Mg ha−1 in 2012/13 and 4.5 Mg ha−1 in 2013/14) than treatments with chlorimuron + metsulfuron-methyl, bensulfuron methyl + pretilachlor, butachlor fb 2,4D, butachlor and cono-weeder. Among, the herbicidal treatments butachlor caused lower grain yield and higher weed density and biomass when compared to the others. Although grain yield was highest in weed-free treatments but net returns and (B:C) benefit cost ratio was highest for pyrazosulfuron ethyl due to high cost of hand weeding. After 15 days of herbicide application, lowest microbial biomass carbon was recorded with bensulfuron methyl + pretilachlor, whereas lower values of dehydrogenase and fluorescein diacetate activities were observed with the application of chlorimuron + metsulfuron-methyl at 15 days after herbicide application. Our results suggest that pyrazosulfuron ethyl is one broad-spectrum and economically effective herbicide for controlling weeds as an alternative to labour consuming hand weeding in boro rice cultivation. Copyright © Cambridge University Press 2017
Bhaduri D.,Indian Agricultural Research Institute |
Bhaduri D.,ICAR National Rice Research Institute |
Purakayastha T.J.,Indian Agricultural Research Institute |
Patra A.K.,Indian Agricultural Research Institute |
And 3 more authors.
Environmental Earth Sciences | Year: 2017
The assessment of soil quality is essential to track changes in soils as a result of management practices. Although a range of soil physical and chemical properties have been used internationally to track change in soil quality, work to evaluate a range of soil biological indicators as a means of monitoring soil quality has been more limited. In order to identify key biological indicators of soil quality, a long-term field trial at the Indian Agricultural Research Institute, New Delhi, was conducted which included tillage (main plots), water (subplots) and nutrient (sub-subplots) treatments for both rice and wheat. Here the combined influence of tillage, water and nutrient management after eight cropping cycles of rice–wheat, on selected soil microbial properties, was assessed. Results showed that non-puddling significantly enhanced dehydrogenase activity (5%), microbial biomass carbon (3%) and potentially mineralizable nitrogen (5%) over puddling, whereas the latter treatment hugely benefited soil respiration (48%) and metabolic quotient (41%) in rice. No-tillage resulted in higher values of soil biological indicators under wheat cultivation. Partial substitution of fertilizer N by farmyard manure, sewage sludge and a combination of (FYM + biofertilizer + crop residues/green manure) increased indicators at higher magnitudes, like dehydrogenase activity (36%), microbial biomass carbon (33%) and potentially mineralizable nitrogen (57%), but reduced the metabolic quotient which implied an accumulation of stable organic C under organic nutrient management uniformly after both the crops. The drainage of irrigation water in rice also increased dehydrogenase activity and microbial biomass carbon. In contrast more frequent (five times and three times) irrigations in wheat significantly increased these indicators. Principal component analysis revealed that both microbial metabolic quotient and dehydrogenase activity were the most promising indicators of soil biological quality in the present experimental setup. © 2017, Springer-Verlag Berlin Heidelberg.
Kumar S.,ICAR Indian Institute of Soil and Water Conservation |
Raizada A.,ICAR Indian Institute of Soil and Water Conservation |
Biswas H.,ICAR Indian Institute of Soil and Water Conservation |
Mondal B.,ICAR National Rice Research Institute
Ecological Indicators | Year: 2016
This paper aims at assess district-wise vulnerability index of the state of Karnataka State, which is predominantly is rainfed and is highly susceptible to climatic variability. Secondary data on relevant indicators were collected to prepare indices viz., crop production losses, exposure, sensitivity and adaptive capacity. Following normalization and using appropriate weights for indicators, these four indices were used for constructing vulnerability index, which can be used a rapid assessment method for prioritizing districts that need measures to moderate the detrimental impact of climate change. It has been observed that Climatic variability caused higher production losses in cereals, pulses and oilseeds in Davangere, Gulbarga and Raichur districts, respectively. Districts like Koppal, Raichur, Bijapur Gulbarga, Gadag, Bagalkote and Bellary were placed under extreme degree of exposure. As per the sensitivity index scores, Kolar district is the most sensitive. Further, Bengaluru (Urban), Dakshin Kannada and Kodagu are ranked first, second and third in terms of adaptive capacity in the state. Overall, vulnerability index scores indicate that Gulbarga, Koppal, Raichur, Bellary, Bagalkote, Bijapur and Belgaum are extremely vulnerable districts in the state. It was also estimated that around 70% of the cultivated area, which supports 60% and 67% of livestock and rural population of the state, respectively are facing ‘extreme to high’ level of vulnerability. The ranking based prioritization of the vulnerable areas calls for a holistic approach for each district or a group of districts to reduce their sensitivity, minimize exposure to rainfall variability through implementation of site-specific and leverage adaptive capacity through better health and education facilities, expansion of employment opportunities in other sectors or reducing over dependence on agriculture. © 2016 Elsevier Ltd
PubMed | ICAR Research Complex for NEH Region, ICAR National Bureau of Plant Genetic Resources and ICAR National Rice Research Institute
Type: Journal Article | Journal: BMC genetics | Year: 2016
Hill rices (Oryza sativa L.) are direct seeded rices grown on hill slopes of different gradients. These landraces have evolved under rainfed and harsh environmental conditions and may possess genes governing adaptation traits such as tolerance to cold and moisture stress. In this study, 64 hill rice landraces were collected from the state of Arunachal Pradesh of North-Eastern region of India, and assessed by agro-morphological variability and microsatellite markers polymorphism. Our aim was to use phenotypic and genetic diversity data to understand the basis of farmers classification of hill rice landraces into two groups: umte and tening. Another goal was to understand the genetic differentiation of hill rices into Indica or japonica subspecies.According to farmers classification, hill rices were categorized into two groups: umte (large-grained, late maturing) and tening (small-grained, early maturing). We did not find significant difference in days to 50% flowering between the groups. Principal component analysis revealed that two groups can be distinguished on the basis of kernel length-to-width ration (KLW), kernel length (KL), grain length (GrL), grain length-to-width ration (GrLW) and plant height (Ht). Stepwise canonical discriminant analysis identified KL and Ht as the main discriminatory characters between the cultivar groups. Genetic diversity analysis with 35 SSR markers revealed considerable genetic diversity in the hill rice germplasm (gene diversity: 0.66; polymorphism information content: 0.62). Pair-wise allelic difference between umte and tening groups was not statistically significant. The model-based population structure analysis showed that the hill rices were clustered into two broad groups corresponding to Indica and Japonica. The geographic distribution and cultivars grouping of hill rices were not congruent in genetic clusters. Both distance- and model-based approaches indicated that the hill rices were predominantly japonica or admixture among the groups within the subspecies. These findings were further supported by combined analysis hill rices with 150 reference rice accessions representing major genetic groups of rice.This study collected a valuable set of hill rice germplasm for rice breeding and for evolutionary studies. It also generated a new set of information on genetic and phenotypic diversity of hill rice landraces in North-Eastern region of India. The collected hill rices were mostly japonica or admixture among the subpopulations of Indica or Japonica. The findings are useful for utilization and conservation of hill rice germplasm.
PubMed | ICAR National Rice Research Institute and Maharana Pratap University of Agriculture and Technology
Type: Journal Article | Journal: The plant pathology journal | Year: 2016
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).
PubMed | ICAR National Rice Research Institute
Type: | Journal: Ecotoxicology and environmental safety | Year: 2016
Application of pesticide in agricultural fields is unnecessary evil for non-target microflora and fauna. Hence, to identify the safer pesticide molecules against non-target microbes, a long-term pesticide experiment was initiated at National Rice Research Institute, Cuttack, India. In the present study, the effect of continuous application of chlorpyrifos (0.5kgha
PubMed | ICAR National Rice Research Institute
Type: Journal Article | Journal: PloS one | Year: 2016
Rice exhibits enormous genetic diversity, population structure and molecular marker-traits associated with abiotic stress tolerance to high temperature stress. A set of breeding lines and landraces representing 240 germplasm lines were studied. Based on spikelet fertility percent under high temperature, tolerant genotypes were broadly classified into four classes. Genetic diversity indicated a moderate level of genetic base of the population for the trait studied. Wrights F statistic estimates showed a deviation of Hardy-Weinberg expectation in the population. The analysis of molecular variance revealed 25 percent variation between population, 61 percent among individuals and 14 percent within individuals in the set. The STRUCTURE analysis categorized the entire population into three sub-populations and suggested that most of the landraces in each sub-population had a common primary ancestor with few admix individuals. The composition of materials in the panel showed the presence of many QTLs representing the entire genome for the expression of tolerance. The strongly associated marker RM547 tagged with spikelet fertility under stress and the markers like RM228, RM205, RM247, RM242, INDEL3 and RM314 indirectly controlling the high temperature stress tolerance were detected through both mixed linear model and general linear model TASSEL analysis. These markers can be deployed as a resource for marker-assisted breeding program of high temperature stress tolerance.
PubMed | ICAR National Rice Research Institute
Type: Journal Article | Journal: Environmental monitoring and assessment | Year: 2016
Impact of elevated CO2 on chlorpyriphos degradation, microbial biomass carbon, and enzymatic activities in rice soil was investigated. Rice (variety Naveen, Indica type) was grown under four conditions, namely, chambered control, elevated CO2 (550 ppm), elevated CO2 (700 ppm) in open-top chambers and open field. Chlorpyriphos was sprayed at 500 g a.i. ha(-1) at maximum tillering stage. Chlorpyriphos degraded rapidly from rice soils, and 88.4% of initially applied chlorpyriphos was lost from the rice soil maintained under elevated CO2 (700 ppm) by day 5 of spray, whereas the loss was 80.7% from open field rice soil. Half-life values of chlorpyriphos under different conditions ranged from 2.4 to 1.7 days with minimum half-life recorded with two elevated CO2 treatments. Increased CO2 concentration led to increase in temperature (1.2 to 1.8 C) that played a critical role in chlorpyriphos persistence. Microbial biomass carbon and soil enzymatic activities specifically, dehydrogenase, fluorescien diacetate hydrolase, urease, acid phosphatase, and alkaline phosphatase responded positively to elevated CO2 concentrations. Generally, the enzyme activities were highly correlated with each other. Irrespective of the level of CO2, short-term negative influence of chlorpyriphos was observed on soil enzymes till day 7 of spray. Knowledge obtained from this study highlights that the elevated CO2 may negatively influence persistence of pesticide but will have positive effects on soil enzyme activities.