Erratic rainfall leading to flash flooding causes huge yield losses in lowland rice. The traditional varieties and landraces of rice possess variable levels of tolerance to submergence stress, but ...gene discovery and utilization of these resources has been limited to the Sub1A-1 allele from variety FR13A. Therefore, we analysed the allelic sequence variation in three Sub1 genes in a panel of 179 rice genotypes and its association with submergence tolerance. Population structure and diversity analysis based on a 36-plex genome wide genic-SNP assay grouped these genotypes into two major categories representing Indica and Japonica cultivar groups with further sub-groupings into Indica, Aus, Deepwater and Aromatic-Japonica cultivars. Targetted re-sequencing of the Sub1A, Sub1B and Sub1C genes identfied 7, 7 and 38 SNPs making 8, 9 and 67 SNP haplotypes, respectively. Haplotype networks and phylogenic analysis revealed evolution of Sub1B and Sub1A genes by tandem duplication and divergence of the ancestral Sub1C gene in that order. The alleles of Sub1 genes in tolerant reference variety FR13A seem to have evolved most recently. However, no consistent association could be found between the Sub1 allelic variation and submergence tolerance probably due to low minor allele frequencies and presence of exceptions to the known Sub1A-1 association in the genotype panel. We identified 18 cultivars with non-Sub1A-1 source of submergence tolerance which after further mapping and validation in bi-parental populations will be useful for development of superior flood tolerant rice cultivars.
The intermittent nature of renewable energy sources results in an interruptible and inadequate power. The integration of the battery energy storage to renewable energy sources provides reliable and ...continuous power to the loads. Further, the high penetration of renewable energy sources raises the power quality problems in the grid. This work deals with performance improvement of PV‐battery energy storage based energy conversion system achieved through implementing a multi‐structural adaptive circular noise estimation control for its grid connected mode. The control is developed for the grid side voltage source converter, which provides the power quality improvement and automated transition from grid connected mode to standalone mode or vice‐versa. It provides multi‐functional features such as harmonics extraction, DC offset elimination, and power quality improvement in PV‐battery energy storage based energy conversion system even at nonlinear loading condition in grid connected mode. In standalone mode, the amplitude and waveform of load voltage are controlled sinusoidal by the voltage control. Performance of PV‐battery energy storage based energy conversion system is studied to validate the acceptability of these controls according to the IEEE‐519 standard.
Potato (
Solanum tuberosum
L.) is the third most important crop after rice and wheat in the world and it is one of the most efficient food crops producing more yield, alimental fibre, high-quality ...protein, minerals and vitamins than wheat, maize and rice per unit area and time and is recognized as a steady and healthy food crop. The production of seed potatoes and its supply chain face special problems because they are big in size, multiply slowly and large quantities are needed to plant the next crop. There is a huge gap between production and supply of quality planting materials of potato. So, it is important to develop a systematic protocol for production of planting materials at large scale. Given such conditions, the conception of an effective and reproducible in vitro regeneration system in popular potato cultivar(s) is crucial to produce high-quality planting material at large scale. Keeping this in mind, to produce genuine propagative material of high phytosanitary, physiological and genetic quality, effective and reproducible in vitro regeneration protocols of potato are indispensable. To attain such goals, potato sprouts were employed as explants sources and inoculated on MS medium fortified with different auxins and cytokinins in fluctuating proportions or alone as well as in diverse concentrations and amalgamations in combination with 30.0 g l
−1
sucrose and 7.5 g l
−1
agar. Induction medium MS3NB (MS + 3.0 mg l
−1
NAA + 1.0 mg l
−1
BA) was more responsive for callus induction (83.00%). Whilst nutrient media MS3BN (MS + 3.0 mg l
−1
BAP + 1.0 mg l
−1
NAA) displayed better in vitro competence, i.e. number(s) of shoot inducing explants (91.00%) and number(s) of shoot(s) per explant (6.50) along with shoot of bigger length (4.60). Whilst higher in vitro rooting response, viz., root proliferating efficiency (84.0%), number(s) of roots (9.0) with higher length (5.1) was exhibited by rooting medium MSIB (MS + 1.0 mg l
−1
IBA). For inducing rooting in vitro, a reduced level of sucrose, i.e. 15.0 g l
−l
, was used. The regenerants were shifted to pots and acclimatized in polyhouse/net house during preliminary ablactating phase. Regenerants showed normal growth and morphology and were found efficacious in the external environment after hardening. Culture medium with higher regeneration aptitude obtained in present investigation may be used for mass in vitro propagation, micro tuber production and different biotechnological works including tailoring transgenic plants resistant/tolerant against diverse biotic and abiotic stresses.
A concern regarding the deterioration in power quality (PQ) has escalated with the high level of integration of renewable energy sources to the utility, primarily in the scenario of a weak ...distribution grid. This paper presents a modified complex variable filter (MCVF)‐based control to enhance the power quality performance of wind–solar photovoltaic (PV) and battery‐based microgrid under the weak grid and dynamic load conditions. An MCVF attenuates the harmonics and DC bias infected voltage and current and extracts the fundamental components from distorted current and voltage. The control scheme for the voltage source converter (VSC) is presented to meet the active power demand of load/grid and attenuates harmonics to control the power quality issues at the point of common coupling. To achieve the round, the clock operation of the microgrid, a battery is interfaced to support the local loads under off‐grid mode. Therefore, the presented VSC controller supplies the continuous power to the local loads and maintains the total harmonic distortion value of grid current within the PQ Standard IEEE‐519‐2014. The simulated and test results are presented to validate the VSC controller in different operating conditions.
In this article, multiple parallel photovoltaic (PV) inverters based microgrid is developed to enhance the reliability and accessibility of electricity in remote areas. A self-adaptive control ...strategy is presented for a microgrid to ensure a seamless transition between the islanded mode (IAM) and grid-connected mode (GCM) of operation with a proportional power sharing. This microgrid consists of two solar PV inverters based on local distributed generation (DG) units. Each PV-inverter unit feeds an active power to support local loads and the power demand of each local load is shared between respective DG units and microgrid. The PV-battery-interfaced main unit with a self-adaptive control strategy in parallel with a PV array supported unit-2 is considered to operate in the IAM and GCM of operation. The control strategy achieves transient free operation during load disturbances, power variation at the PV array side, and off-grid operation. Moreover, the microgrid ensures high-quality performance at the point of common coupling and provides the seamless transition between GCM and IAM to guarantee a continuous power to critical loads. The microgrid simulation and experimental results are presented under various operating conditions, such as load variation, intermittent power generation, and automated mode transition between GCM and IAM.
This paper presents a modified power control (MPC) for a grid-interfaced autonomous microgrid connecting multiple solar photovoltaic inverter (SPI) units. An MPC provides the automatic transition ...capability between grid-tied mode (GTM) and an islanding mode (IAM) for a microgrid consisting of multiple parallel-operated SPIs. In GTM, SPIs extract PV power to fulfil the load demand, and the rest power is fed to the grid at the unity power factor (UPF) by working in the current control mode (CCM). Upon grid failure, the main SPI unit inherently changes from CCM in GTM to voltage control mode (VCM) in the IAM state to achieve an uninterruptable power supply to loads. When the grid restores, the main SPI unit near the point of common coupling (PCC) re-synchronizes the PCC voltage with grid voltage in the microgrid and control shifts back to GTM. A seamless mode transition in the microgrid is achieved without rearrangement of control formation, and power distribution between the parallel SPI units is achieved without communication setup. This reduces the cost of remote communication setup for resynchronization and saves the complexity. Moreover, MPC accurately regulates the reference grid current of SPIs when the load demand fluctuates. The MPC method combines the adaptive integrator filter (AIF), which attenuates the harmonics from the input signal to strictly control the power factor at PCC and maintains the total harmonics distortion (THD) of grid current and PCC voltage according to the IEEE stand. 519. The performance of the presented MPC method is evaluated via a simulation and test results.
This work presents a hybrid control method (HCM) for inverters in a single-phase AC grid-interactive photovoltaic (PV) microgrid connecting multiple PV inverter (PVI) units. The HCM is incorporated ...into a single control method employing three cascaded loops -grid current loop, voltage control loop and improved third order adaptive integrator-quadrature signal generator (ITOAI-QSG). The HCM is used for mode transitions between the grid integrated mode (GIM) to islanding mode (IAM) and vice-versa, and this confirms the seamless transfer between the modes without rearranging the control structure. In GIM, the presented controller regulates the grid current and provides dynamic grid support by the reactive power compensation. In IAM, the controller changes from the grid current control to the voltage control to adjust the PV inverter's output voltage. The control method is presented for a parallel-operated single-stage where PV panels are interfaced with the inverters with independent maximum power point tracking (MPPT) to harvest maximum power. The battery energy storage (BES) is interfaced with the main PVI unit to support the load demand in peak demand periods and maintains the power balance in IAM. The charging and discharging profiles of BES are achieved by a DC-DC bidirectional converter (DBC). Test results verify the performance of the developed control.
In this work, a multifunctional control is implemented for a solar photovoltaic (PV) integrated battery energy storage (BES) system (PVBES), which operates both in the grid-connected mode (GCM) and a ...standalone mode (SAM). This system addresses the major issues of integrating power quality enhancement along with the solar PV generation. Thus, a multifunctional control of voltage source converter (VSC) is implemented to provide the load compensation, harmonics mitigation, unity power factor, and an automated transition between GCM and SAM in PVBES. A single VSC is used to control the active power and to maintain the power quality in this PVBES. Furthermore, due to an automated transition in the system, the local loads have continuous power irrespective of the grid accessibility. The main challenges addressed are the operation of an automated transition between GCM and SAM with the least disturbance to the nonlinear loads. The integration of a BES enables the SAM operation and improves the reliability of the PVBES. The charging and discharging of BES are controlled by using a dc-dc bidirectional converter. The performance of the implemented controls is tested using a real-time processor (dSPACE-1202) and validated through test results for steady state and dynamic conditions. In all operating conditions, the harmonics content of the grid current is maintained less than 5%, which follows the IEEE standard 519-2014.
This article aims to develop a solar- battery energy storage (BES) based system, which ensures an uninterruptable supply to loads irrespective of availability of the grid. This system comprises of a ...solar photovoltaic (PV) array, a BES, the grid and local residential loads. A new control is implemented such that the active power demand of residential loads, is fed from the PV array, a BES unit and the utility grid. In this system, the power control operates in different power modes, which delivers the benefits to the end users with an integration of BES and an excess of PV array power, which is sold back to the grid. For this, an effective control logic is developed for the grid tied voltage source converter. Moreover, this system deals with the issue of an integrating power quality enhancement along with the power generation from the solar PV source. The cascaded delayed signal cancellation based phase locked loop is implemented for grid synchronization during the grid voltage distortion. The developed control is easily implemented in a real time controller (dSPACE-1202). Test results validate the performance of the implemented control in different operating conditions such as varying solar power generation, load variations and unavailability of the grid.
•Marker-assisted backcross improvement of mega varieties of rice.•QTLs for drought, submergence and salt tolerance.•Foreground and recombinant selection.•Background selection using high density 50K ...SNP chip.
Rice is a staple cereal of India cultivated in about 43.5Mha area but with relatively low average productivity. Abiotic factors like drought, flood and salinity affect rice production adversely in more than 50% of this area. Breeding rice varieties with inbuilt tolerance to these stresses offers an economically viable and sustainable option to improve rice productivity. Availability of high quality reference genome sequence of rice, knowledge of exact position of genes/QTLs governing tolerance to abiotic stresses and availability of DNA markers linked to these traits has opened up opportunities for breeders to transfer the favorable alleles into widely grown rice varieties through marker-assisted backcross breeding (MABB). A large multi-institutional project, “From QTL to variety: marker-assisted breeding of abiotic stress tolerant rice varieties with major QTLs for drought, submergence and salt tolerance” was initiated in 2010 with funding support from Department of Biotechnology, Government of India, in collaboration with International Rice Research Institute, Philippines. The main focus of this project is to improve rice productivity in the fragile ecosystems of eastern, northeastern and southern part of the country, which bear the brunt of one or the other abiotic stresses frequently. Seven consistent QTLs for grain yield under drought, namely, qDTY1.1, qDTY2.1, qDTY2.2, qDTY3.1, qDTY3.2, qDTY9.1 and qDTY12.1 are being transferred into submergence tolerant versions of three high yielding mega rice varieties, Swarna-Sub1, Samba Mahsuri-Sub1 and IR 64-Sub1. To address the problem of complete submergence due to flash floods in the major river basins, the Sub1 gene is being transferred into ten highly popular locally adapted rice varieties namely, ADT 39, ADT 46, Bahadur, HUR 105, MTU 1075, Pooja, Pratikshya, Rajendra Mahsuri, Ranjit, and Sarjoo 52. Further, to address the problem of soil salinity, Saltol, a major QTL for salt tolerance is being transferred into seven popular locally adapted rice varieties, namely, ADT 45, CR 1009, Gayatri, MTU 1010, PR 114, Pusa 44 and Sarjoo 52. Genotypic background selection is being done after BC2F2 stage using an in-house designed 50K SNP chip on a set of twenty lines for each combination, identified with phenotypic similarity in the field to the recipient parent. Near-isogenic lines with more than 90% similarity to the recipient parent are now in advanced generation field trials. These climate smart varieties are expected to improve rice productivity in the adverse ecologies and contribute to the farmer’s livelihood.
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