Central Agricultural University

About: Central Agricultural University is a education organization based out in Imphal, Manipur, India. It is known for research contribution in the topics: Population & Agriculture. The organization has 1116 authors who have published 1157 publications receiving 9217 citations.

Microsatellite marker dependent genetic divergence assessment within and among heterotic groups of tropical maize inbred lines

Abstract: Use of microsatellite markers can be helpful in assessing the nature and extent of genetic diversity among inbred lines, assigning inbred lines efficienly to heterotic groups and making the choice of heterotic parents to develop new hybrids. A study was conducted to determine the heterotic groups of 18 inbred lines of maize including three inbred testers and to examine the nature and extent of divergence within and between heterotic groups of inbred lines based on the analysis of targeted microsatellite sites. Using hybrid index and hybrid mean values obtained from the results of experimental trials conducted over the two seasons as the indices, inbred lines were classifie into three heterotic groups. Microsatellite profiing with a panel of 28 primer pairs covering all chromosomes revealed ample genetic polymorphism, which allowed unique genotyping and unambiguous classificaion of inbred lines. Basically, the inbred lines and testers were differentiated into four genotypic groups. Principal coordinate analysis based on similarity indices and spatial ordination of the genetic profile showed four well define genotypic groups of 18 inbreds. The distribution pattern of the entries into different heterotic groups formed on the basis of hybrid index value and hybrid mean value corresponded with the microsatellite markers based groups to the extent of 75% and 67% in the firs heterotic group, 40% and 29% in the second heterotic group and 33% and 40% in the third heterotic group, respectively. Overall coincidences of inbred lines in heterotic groups based on microsatellite markers with the hybrid index value and hybrid mean value based heterotic groups (47% and 40%, respectively) indicated that microsatellite markers may be effectively and efficienly utilized to assign the inbred lines to heterotic groups for the purpose of reducing the number of single crosses to be generated and evaluated. Average genetic divergence revealed within and between heterotic groups by the microsatellite markers may be utilized as the criterion for parental line selection during development of experimental hybrids

Biochemical, physiological (haematological, oxygen-consumption rate) and behavioural effects of mercury exposures on the freshwater snail, Bellamya bengalensis.

Abstract: The widespread occurrence of Mercury (Hg) and its derivatives in the aquatic environment and risks to the health of local populations has necessitated investigations into its toxic effects on sessile species. The toxicity of Mercury was observed sequentially from 96 h acute exposure regime (behavioural endpoints) to chronic durations (haematological and biochemical toxicity endpoints) in Bellamya bengalensis. Time-dependent lethal endpoints for acute toxicity (LC50) of mercury i.e., 24,48,72 and 96 h were estimated as 0.94, 0.88, 0.69 and 0.40 mg/l respectively. Threshold effect values i.e., LOEC (Lowest Observed Effect Concentration), NOEC (No Observed Effect Concentration) and MATC (Maximum Acceptable Toxicant Concentration) at 96 h were found to be 0.10, 0.05, 0.039 mg/l respectively. The study of oxygen consumption rate and behavioural changes during acute toxicity and haematological and biochemical responses during chronic toxicity to sublethal concentrations (10% and 20% of 96 h LC50) of mercury to the snail were also conducted. The organisms showed initial elevation at 24 h but later gradual decrease in oxygen consumption rate with the increase of concentration of mercury and time of exposure. For behavioural studies, variable test concentrations from 0.00 to 1.00 mg/l were used for 24, 48, 72 and 96 h. The crawling activity and clumping tendency decreased with the progress of time at all treatment periods and stopped ultimately at 96 h of exposure from 0.7 mg/l onwards whereas touch reflex was not observed at 96 h exposure at all treatments except at 0.09 mg/l. In haemocyte count, no significant variation was observed among control values between various exposure periods (p > 0.05) though variations were observed in sub-lethal concentrations versus control at all treatment duration (7, 14, 21, 28d, p

Fractal analysis of aggregates: Correlation between the 2D and 3D box-counting fractal dimension and power law fractal dimension

Abstract: Fractal dimension (Df) has been extensively used for many years to characterize the morphological properties of aggregate systems. There are two main methods to estimate the fractal dimension of aggregates, namely the box-counting (BC) and power law (PL) methods. However, the relationship between the BC fractal dimension (Df, BC) and PL fractal dimension (Df, PL) has not been discussed yet. In this work, a series of three-dimensional aggregates with different input parameters (Df, PL and the number of primary particles) is generated by a tunable aggregation model. Then, the fractal dimensions (Df, BC, 3D) of all the aggregates are estimated by the 3D BC method. The relationship between Df, BC, 3D and Df, PL is investigated. We found that Df, BC, 3D is greater than Df, PL when Df, PL≤ 2.5. However, the situation is reversed when Df, PL> 2.5. Further, a novel projection method is proposed and applied to all the 3D aggregates to obtain their 2D projection images. In this projection method, the minimum projection overlapping area of all the primary particles in the aggregate is considered. Then, the fractal dimensions (Df, BC, 2D) of 2D projection images are estimated using the 2D BC method. Finally, correlations between Df, BC, 3D and Df, PL with Df, BC, 2D are established.

Conservation Agriculture: Economic Perspective and Future Challenges

Abstract: Conservation Agriculture (CA) is an approach for designing and management of sustainable and resource-conserving agricultural systems. It seeks to conserve, improve and make more efficient use of natural resources through integrated management of soil, water, crops and other biological resources in combination with selected external inputs. Conservation agriculture has emerged as an effective strategy to achieve goals of sustainable agriculture worldwide. It has the potential to address increasing concerns of serious and widespread problems of natural resource degradation and environmental pollution, while enhancing system productivity. The primary focus of developing and promoting RCT practices has been the development and adoption of zero tillage cum fertilizer drill for sowing wheat crop in rice–wheat system. Other interventions being tested and promoted include raised-bed planting system, laser-aided land-leveling equipment, residue management alternatives, alternatives to rice-wheat cropping system in relation to RCT technologies, etc. CA offers an opportunity for arresting and reversing downward spiral of resource degradation, decreasing cultivation costs and making agriculture more resource-use-efficient, competitive and sustainable. ‘Conserving resources-enhancing productivity’ has to be new mission. Availability of machinery / equipment for promotion of resource conservation technologies is a prerequisite for achieving targets of agricultural production. Availability of implement at economical cost is major constraint in promotion of bed planting of crops. Likewise, machinery is not available for crop residue management that is impeding acceleration of this practice. Organizing farmers’ days, holding of field demonstrations, cross-farm visits of extension experts and effective use of mass media i.e. print and electronic media for transfer of technology may play a major role in promotion of resource conservation technologies amongst farming community. Capacity building of farmers to acquire, test and adopt technologies through participatory approach will enable them to seek resource conservation technologies for their farms and thus they can reduce their production cost and combat production constraints. Improvement in coordination among various stakeholders (research, extension service, farmers, service providers, agricultural machinery manufacturers, etc.) for transfer of technologies will play a pivotal role in accelerating adoption of new interventions.

Highlighting the compound risk of COVID-19 and environmental pollutants using geospatial technology.

Abstract: The new COVID-19 coronavirus disease has emerged as a global threat and not just to human health but also the global economy. Due to the pandemic, most countries affected have therefore imposed periods of full or partial lockdowns to restrict community transmission. This has had the welcome but unexpected side effect that existing levels of atmospheric pollutants, particularly in cities, have temporarily declined. As found by several authors, air quality can inherently exacerbate the risks linked to respiratory diseases, including COVID-19. In this study, we explore patterns of air pollution for ten of the most affected countries in the world, in the context of the 2020 development of the COVID-19 pandemic. We find that the concentrations of some of the principal atmospheric pollutants were temporarily reduced during the extensive lockdowns in the spring. Secondly, we show that the seasonality of the atmospheric pollutants is not significantly affected by these temporary changes, indicating that observed variations in COVID-19 conditions are likely to be linked to air quality. On this background, we confirm that air pollution may be a good predictor for the local and national severity of COVID-19 infections.