S. K. Dwivedi

Paclobutrazol-induced alleviation of water-deficit damage in relation to photosynthetic characteristics and expression of stress markers in contrasting wheat genotypes

Our experiment was conducted in order to find out effects of paclobutrazol (PBZ; 30 μl l–1) on morphology, photosynthetic process, and stress markers under water surplus and deficit conditions in several wheat genotypes. Study revealed that relative water content (RWC), photosynthetic rate, and maximal quantum yield of PSII (FV/FM) was improved after a PBZ application both under irrigation and water deficit across the genotypes, while the stomatal conductance was reduced. Further, the application of PBZ led to reduced leaf area in wheat genotypes. Moreover, a proline content was higher in the wheat genotypes under water stress as compared to the irrigated plants. The application of PBZ led to downregulation of the proline content under water deficit, while there was no significant change in the content and activity under irrigation with or without the PBZ treatment. These findings indicated that due to the application of PBZ the wheat genotypes might sense a lower stress level (indicated by the proline content) and better drought tolerance (according to RWC and photosynthetic characteristics).

Induction of water deficit tolerance in wheat due to exogenous application of plant growth regulators: membrane stability, water relations and photosynthesis

Our experiment was carried out in order to explore effects of plant growth regulators (PGR; thidiazuron, paclobutrazol, and ascorbic acid) on physiological traits of wheat genotypes under water surplus and deficit conditions. Study revealed that relative water content, membrane stability index, chlorophyll content, photosynthetic rate (PN), and maximal quantum yield of PSII improved with PGRs application across the genotypes both under irrigation and water stress. The response of HD 2733 genotype was more positive toward PGRs treatment as compared to other genotypes under water stress. Higher PN and chlorophyll contents were observed in HD 2987 followed by C 306 genotype under water-stress conditions. Moreover, Rubisco small subunit (SSU) expression was lower in wheat genotypes under water stress as compared to irrigated conditions. Application of PGRs led to upregulation of SSU under water stress, while no significant change was found in Rubisco level and activity under irrigated condition in dependence on PGRs treatments. Yield-related traits showed also significant reduction under water-stress conditions, while application of PGRs enhanced the yield and its components. Results indicated that the PGRs exhibited a positive interaction and synergetic effect on water stressed wheat plants in terms of photosynthetic machinery and yield.

Effect of different rice establishment methods on soil physical properties in drought-prone, rainfed lowlands of Bihar, India

To enhance productivity, alleviate environmental and management constraints, and enhance farmers’ incomes in the rice–wheat cropping system of the Indo Gangetic Plains, new approaches that are labour-saving, more productive and sustainable need to be developed. Most systems of rice cultivation use puddling to prepare the seedbed and control weeds in rice fields of rainfed, stress-prone environments. This practice might be helpful to reduce weed pressure and obtain slightly higher productivity, but might have negative impacts on soil physical properties. A better understanding is needed of the comparative advantage of unpuddled rice fields for maintaining good soil physical properties. To study the effect of different rice establishment methods on soil physical properties in a rice–wheat cropping system, we analysed soil samples in 2 years (2012–13 and 2013–14) from an experiment testing puddled and unpuddled rice-establishment methods. The treatments were: (i) puddled, transplanted with best management practices; (ii) puddled, transplanted with the system of rice intensification; (iii) unpuddled, transplanted; and (iv) unpuddled, direct-seeded. Omission of puddling improved soil physical properties such as bulk density, penetration resistance, aggregation stability and cracking behaviour. The absence of soil disturbance also improved soil aggregation, average mean-weight diameter and water-stable aggregates. Thus, unpuddled conditions increased the macro-aggregate fraction by 18–33%. By contrast, the higher frequency of smaller macro-aggregates (0.053–0.25 mm diameter) in puddled conditions clearly indicated the breakdown of larger macro-aggregates (>0.25 mm) into smaller size fractions. Puddled treatments were also characterised by a hard pan and wider, longer and deeper cracks, with a crack volume more than three times higher in puddled conditions. Unpuddled treatments recorded slightly higher nutrient contents in the topsoil. The study reveals that puddling deteriorates soil health. However, a long-term study is required for a better understanding of the soil changes related to different rice establishment technologies.

Minimization of Test Suites for Fuzzy Object-Oriented Database

Test suite optimization is an effective method that is used to minimize or reduce the time and cost of testing. There are several researchers and software professionals have used this method or techniques to enhance the correctness and effectiveness of test suites/cases. These approaches optimize test suite for a single objective but fuzzy logic with certain algorithm is used to optimize the test cases/suites for multi objective selection processes. Therefore, in the present work an approach of optimization or minimization of test suites is proposed for the designed fuzzy object-oriented database and also applied this approach to reduce the complexity of the designed database. The main objective of our approach is to minimize and find the test suite that is best optimal for multiobjective testing.

Data Cube Representation for patient Diagnosis System Using Fuzzy Object-Oriented Database

In the current scenario, everyone wants to store and fetch the information in an easy and faster way. Therefore, the data cube is one of the leading tools in these days that facilitate the user to store and retrieve the decision support information in a faster manner with ease. In this paper the patient diagnostic system (PDS) is proposed for the patient who is suffered from the several types of fever and modeling of fuzzy object-oriented database. An attempt is made to design a three dimensional data cube for the fuzzy object-oriented database for storing the vague or imprecise information in it. A class, sequence and activity diagrams are also designed for the graphical representation of the proposed work through the well known modeling language i.e. Unified Modeling Language (UML).

Nutrient uptake and content in sorghum cultivars (Sorghum bicolor L) under summer environment

Performance of 10 sorghum cultivars (CSH13, CSH14, CSH16, CSH25, CSH30, CSV15, CSV20, CSV23, CSV27 and SPV462) for nutrient composition and nutrient uptake was determined under two dates of sowing (16 February and 3 March) at ICAR Research Complex for Eastern Region Patna, during summer season of 2015 and 2016. Study revealed that difference in sowing dates did not influence the nutrient contents (N, P, K, S, Zn, Fe and Cu) of grain of sorghum. But in case of stover, K, Zn and Cu content did change in two dates of sowing, while the content of other nutrients does not change in stover also. The 16th February sown crop had significantly higher K, Zn and Cu content in stover compared to 3rd March sown. Total uptakes of N, P and Zn were higher with 3rd March sown crop compared 16th February crop. The uptake of N, P and Fe in grain was significantly higher with 3rd March sown crop as compared to 16th February sown crop. However, N, P, K and Zn uptake in stover was markedly higher with 3rd March sown crop. Further, 3rd March sown crop had significantly higher total N, P and Zn uptake than 16th March sown crop. Sorghum cultivars varied significantly in nutrient contents and uptake (N, P, K, S, Zn, Fe and Cu) in grain and stover except K content in grain. Total uptake of N was higher with CSH13, while total uptake of P was maximum with CSV27 and K with CSV23. With respect to the micronutrient, total uptake of Zn and Fe was higher with CSH13, while total uptake of Cu was maximum with CSV20. Hence, use of nutrient efficient cultivars like CSH13, CSH16, CSV27 and SPV 462 with optimum sowing time is necessary to improve nutrient-use efficiency of summer sorghum. Further, cultivar ‘SPV 462’ showed the higher photosynthetic rate (PN), stomatal conductance (gs) and intrinsic transpiration ratio as compared to other genotypes irrespective of the sowing dates.The micro-nutrient deficiency in human food and animal feed and fodder in rural areas could be addressed by selecting appropriate sorghum cultivars rich in micro-nutrient (Fe, Zn and Cu) contents in grain and stover.

Effect of Climate Change on Growth and Physiology of Rice-Wheat Genotypes

Under the changing climatic condition, both CO2 and temperature are the key variables that may cause significant changes in crop productivity. To understand the effect of these key variables of climate change on rice and wheat genotypes, a study was conducted under different sets of varying environments inside open top chambers (OTCs). The sets of conditions were ambient condition, ~25 % higher CO2 than ambient, 25 % higher CO2 + 2 °C ˃ ambient temperature, and 2 °C higher than the ambient temperature. Finding of the study showed that C3 crops (rice and wheat) respond positively toward increasing atmospheric CO2 in the absence of other stressful conditions, but the beneficial direct impact of elevated CO2 can be offset by other effects of climate change, such as elevated temperature. Climate changes affect the development, growth, and productivity of plants through alterations in their biochemical, physiological, and morphogenetic processes. The rising level of atmospheric CO2 led to the fertilization effect on C3 crops which in turn improved their growth and productivity. Increasing CO2 concentration in the atmosphere could lead to higher crop yields. Increased temperatures during the growing period may also reduce CO2 effects indirectly, by increasing water demand. Among different rice genotypes, IR83376-B-B-24-2 was highly responsive, while IR84896-B-127-CRA-5-1-1 was least responsive toward elevated CO2. Moreover, the response of wheat genotypes HD 2967 (4.18 t ha−1) and HD 2733 (4.17 t ha−1) was more positive toward elevated CO2 as compared to other genotypes. In terms of tolerance to heat, the wheat genotype Halna followed by DBW 17 was least affected due to elevated temperature as compared to other genotypes. Finding also suggests that various physiological traits, viz., content of sugar, stability of membrane (MSI %), plant leaf water status (RWC %), and photosynthetic rate, were improved under elevated level of CO2. However, rising temperature led to the negative response in terms of physiological traits. Advance knowledge of the future climate change scenarios in the zone on agroclimatic zone level would help in determining future climate risks and in identifying vulnerable areas to serve as the basis for crop planning and identification of suitable genotypes.

Rice Breeding for Drought Tolerance Under the Changing Climate Scenario

Rice (Oryza sativa L.) is one of the most important staple food crops for about two third of the world’s population. Rice is cultivated in diverse ecosystems extending from rainfed upland to deep water. The rainfed rice covers ~45 % of the world’s rice area. In a rainfed ecosystem, the recurrent event of drought has been attributed as the major reason to the low productivity. Present speculations regarding higher frequency of drought event along with a 1.1–6.4 °C rise in average global soil surface temperature by the end of this century pose an alarming threat to the production and productivity of rice posing a question mark to the food security of Asia. Drought is the greatest single yield-reducing factor among all other stresses influencing more than 23 M ha area of South and Southeast Asia. Out of the total 20.70 M ha located in India, ~16 M ha of area falls in eastern India including 6.3 M ha of upland and 7.3 M ha of lowland areas, which are highly susceptible to drought condition. Rice crop is very susceptible to soil moisture deficit and high-/low-temperature stresses, particularly at the reproductive stage. The majority of the existing high-yielding and traditional varieties of rice in the eastern part of India are very susceptible to moisture stress (drought). The majority of the high-yielding as well as traditional varieties of rice cultivated in the eastern part of India are very susceptible to moisture stress (drought). Farmers of drought-prone areas require such type of rice varieties that give them with high yield in years of normal rainfall and sustainable good yield in drought years. In this scenario, 42 advanced rice breeding lines were evaluated under drought stress at the reproductive stage with the objective of identifying drought stress-tolerant genotypes. The effect of drought stress on morphophysiological and biochemical traits was also studied. In the study, significant yield reduction was noticed almost in all rice genotypes under drought stress condition in comparison to control (non-stress). The varying responses of genotypes to the applied drought stress condition indicate its drought tolerance capacity. Grain yield was varied from 1.26 to 4.76 t/ha and 2.47–7.48 t/ha under stress and control condition, respectively. Based on preliminary screening, rice genotypes, viz., IR88867-4-1-1-4 (4.76 t/ha), IR88964-24-2-1-4 (4.73 t/ha), and IR88867-9-1-1-4 (4.55 t/ha), showed tolerance to drought at the reproductive stage as compared to check varieties Lalat (2.42 t/ha), IR64 (2.04 t/ha), and Sahbhagi Dhan (2.87 t/ha). Reproductive-stage drought also caused a decline in relative water content (RWC), membrane stability index (MSI), and plant biomass and an increase in grain sterility. These drought stress-tolerant rice genotypes may be cultivated in large areas of rainfed ecology where the occurrence of reproductive-stage drought is very frequent, especially in eastern India.

Diversity Among Rice Landraces Under Static (Ex Situ) and Dynamic (On-Farm) Management: A Case from North-Western Indian Himalayas

Crop genetic diversity is the building block of sustainable agricultural development. Crop landraces contain enormous genetic diversity. The genetic structure of rice landraces is an evolutionary approach to existence and performance, especially under rainfed and to some extent under irrigated conditions in valleys and organic inputs in Himalayan agroecosystems. The combined effects of farmer and natural selection led to the building of genotypes representing diverse combinations of traits. The better understanding into the dynamics of genetic resources of rice is needed in order to identify detrimental evolutionary patterns and draw up conservation priorities. During the last two to three decades, the introduction of high-yielding varieties as well as important changes in rice farming systems has led to the loss of genetic diversity particularly from valleys in lower elevation ranges. In order to develop a rational conservation plan, in global climate change scenario, a conservation concept is required that goes far beyond ex situ conservation. In situ conservation on farm has been reflected as a backup and complementary strategy to ex situ conservation. In this scenario, the current study demonstrated farmer management and temporal evolution of rice genetic diversity in traditional production systems. The study also compared gene bank-conserved (ex situ) populations and on-farm-managed (in situ) landrace populations of same landraces Jaulia and Thapachini and revealed a greater number of alleles per locus under on-farm-managed populations as compared to static management. The marker diversity by using STMS indicates the genetic diversity among populations resulting from combined effects of many evolutionary forces operating within the biological and historical context of the landrace. The results indicated the low diversity of the populations under static management. On the other hand, the variations in adaptations indicate the degree to which populations are adapted to their environments and their potential for continued performance or as donors of characters in plant breeding. It also provides particular information on loss of diversity over time and space at allelic and genotype level. This piece of writing is a step towards understanding the impact of traditional farmer management on rice landrace populations in Himalayan agroecosystems of India.

Impact, Adaptation Strategies and Vulnerability of Indian Agriculture Towards the Climate Change

Change in climate is one of the most important worldwide environmental challenges, with implication for production of food, supply of water, health, energy resources, etc. Proper scientific understanding with coordinated action at global level is required for addressing the climate change. Climatic system of the earth has apparently changed on both regional as well as global scales since the pre-industrial era. The Intergovernmental Panel on Climate Change (IPCC) declared that the daily mean temperature (globally) may be increased between 1.4 and 5.8 °C by the twenty-first century. Historically, the responsibility for greenhouse gases (GHGs) emissions’ increase lies largely with the developed world, though the developing nations are likely to be the major cause of a growing proportion of future emissions of GHGs. Agriculture sector is not only sensitive to climate change but also one of the key drivers for climate change. The sensitivity of climate towards agriculture is uncertain, as there is regional variation of climatic factors like rainfall, temperature (maximum and minimum), crop stands and different cropping system, soils properties and management practices. Overall, in the winter season (rabi), rise in the average temperature is likely to be much higher than in the monsoon season (kharif). Agriculture is one of the sectors where impact of climate change will be significant, and it will affect every part of agriculture including crops, fisheries, livestock, etc. Hence, it is necessary to identify the possible impacts of climate change on agricultural productivity and its allied sectors in order to recommend adaptation and mitigation strategies. Developing countries is reducing the vulnerability of their natural and socio-economic systems to the projected climate change that is the issue of the highest importance for developing countries. Developing countries will face the challenge of promoting mitigation and adaptation strategies for climate change, bearing the cost of such an effort, and its implications for social and economic development. We conclude by making interim recommendations on the practical strategies needed to develop a more resilient and dynamic world agriculture in the twenty-first century.