Modeling and simulation of multifaceted properties of X2NaIO6 (X = Ca and Sr) double perovskite oxides for advanced technological applications.

CONTEXT: In this study, the authors have investigated the structural, optoelectronic, thermoelectric, and thermodynamic properties of Ca2NaIO6 and Sr2NaIO6 double perovskite oxides. Both materials exhibit semiconductor behavior with direct band gaps (Eg) of 0.353 eV and 0.263 eV, respectively. Optical parameters like absorption coefficient α(ω), reflectivity R(ω), dielectric constants, and refractive index have been calculated. The most notable absorption peaks are identified at 5.52 eV (equal to 108.33 × 104 cm-1) in the case of Ca2NaIO6 and at 11.16 eV (equivalent to 118.17 × 104 cm-1) for Sr2NaIO6. These findings suggest a promising outlook for applications in optoelectronics. Moreover, their commendably low thermal conductivity and a high figure of merit, particularly at low temperatures (100 K), indicate their effectiveness as thermoelectric materials. This analysis underscores that these materials hold potential as suitable candidates for n-type doping, making them well-suited for use in thermoelectric devices. Studying thermal properties, including thermal expansion, bulk modulus, acoustic Debye temperature, entropy, and heat capacity, contributes to understanding the materials' thermodynamic stability. The titled materials are dynamically stable. The analysis of these double perovskite materials highlights their potential across various technological applications due to their advantageous structural, electronic, optical, and transport properties, offering new possibilities in material science and technology development. METHODS: The study utilized the full potential linearized augmented plane wave (FP-LAPW) method in conjunction with density functional theory within the WIEN2k simulation code. This approach is widely recognized as one of the most dependable methods for evaluating the photovoltaic characteristics of semiconducting perovskites. The thermoelectric properties were ascertained using the rigid band approach and the constant scattering time approximation, both implemented in the BoltzTraP computational code.

Electronic structure, theoretical power conversion efficiency, and thermoelectric properties of bismuth-based alkaline earth antiperovskites.

CONTEXT: This research paper investigates the properties and potential applications of antiperovskite materials. Antiperovskites are a class of materials with a unique crystal structure, where the central atom is surrounded by a cage of anions. We review recent research on antiperovskite-based materials for energy storage, photovoltaics, catalysis, and sensors. We discovered that these materials display direct band gap semiconductors, strong absorption in the visible (VIS), ultra-violet (UV), and near infrared regions (NIR) based on their fundamental features, which is the most admirable quality that may be found in many optoelectronic devices. Both mechanical and thermodynamic stability have been confirmed for these materials. We discovered that these materials exhibit high figures of merit through the calculation of transport properties, which makes them a promising candidate for thermoelectric devices. It is anticipated that the proposed material BiPMg3, which has a theoretical efficiency of 11.5%, will make a suitable photovoltaic absorber. This paper highlights the potential of these materials for future technological advancements. METHODS: Herein, we have used most authentic techniques to compute fundamental physical properties of these antiperovskites. Full-potential linear augmented plane wave (FP-LAPW) method has been used to investigate electronic, magnetic, optical properties, and make antiperovskites attractive for a variety of applications. In light of its implementation, we have checked the theoretical power conversion efficiency by first principles spectroscopic screening methodology, and inspect the fundamental physical parameters of antiperovskites, focusing on their potential as functional materials for energy and information technologies.

Progress in theoretical study of lead-free halide double perovskite Na2AgSbX6 (X = F, Cl, Br, and I) thermoelectric materials.

CONTEXT: Herein, we have studied progressively novel metal lead-free halide double perovskite renewable energy materials. Due to their potential use in electronic devices, researchers have investigated these materials with a lot of interest. From the electronic structure, we have found that these are the indirect band gap semiconductors within the range between 1.273 and 3.986 eV. Optical parameters such as dielectric constant, electrical conductivity, and absorption coefficient have also been investigated, which have shown that these materials have potential use in photovoltaics. We have checked stability issues by thermodynamic parameters and phonon spectra. We have found them thermally stable; however, the phonon spectra show their dynamical instability and except for Na2AgSbF6 and Na2AgSbI6, the remaining compounds are weak in mechanical stability. For another futuristic purpose, thermoelectric parameters such as Seebeck coefficient, power factor, and figure of merit have also been calculated, which again verifies that these materials may be very useful in thermoelectric devices. Most of the parameters have been computed for the first time. METHODS: We have performed this computational work using WIEN2k simulation code, which is based on the full-potential linearized augmented plane wave (FP-LAPW) technique. It is one of the most reliable techniques to calculate the photovoltaic properties of semiconducting perovskites. The interaction between ion-core and valence electrons was dealt with within the PAW technique as implemented in Vienna Ab initio Simulation Package (VASP).

Stability and suitability of genotypes and environment to Ascochyta blight of chickpea.

Ascochyta blight (AB) is a major biotic constraint to chickpea production internationally. The disease caused by the phytopathogenic fungus Ascochyta rabiei is highly favored by prolonged spells of low temperature and high humidity. The disease scenario is expected to aggravate in the near future as a result of rapidly changing climatic conditions and the emergence of fungicide-resistant pathogen strains. Tapping into host-plant resistance is the most logical way to preempt such a crisis. Presently, high levels of stable resistance against AB are yet to be identified from the chickpea gene pool. The present study was aimed at facilitating this process through multi-environment testing of chickpea genotypes. Using the GGE biplot analysis method, we could identify three genotypes, viz., ICCV 16508, ICCV 16513, and ICCV 16516, from the International Ascochyta Blight Nursery, which showed consistent moderate resistance reactions across all the tested environments. Moreover, we were able to evaluate the test locations for their suitability to support AB screening trials. Ludhiana and Palampur locations were identified as the most ideal for continual screening in the future. Controlled environment screening at the ICRISAT location offered to reduce large plant populations to small meaningful sizes through initial screening under controlled environment conditions. This study will further improve the scope of phenotyping and sources of stable resistance to be utilized in future AB resistance breeding programs.

Identification of promising chickpea interspecific derivatives for agro-morphological and major biotic traits.

The wild Cicer species is well-known for having climate-resilient and productivity-enhancing traits of interest. Therefore, wide hybridization could be used as a realistic strategy for introgressing prospective traits from wild species into the cultivated gene pool. The present study was, thus, undertaken to evaluate F7 chickpea interspecific derivatives derived from Cicer reticulatum Ladiz. and C. echinospermum P. H. Davis wild annual Cicer species. As a result, a set of six interspecific crosses were advanced using the single seed descent (SSD) method of breeding. The F7 generation of these crosses was assessed in two diverse agro-ecological regions of India. The data revealed a wide range of variation with respect to seed yield and its important component traits, which resulted in the identification of the most promising derivatives carrying desirable characters as indicated by range, mean, and coefficient of variation. Further, fruitful heterosis was also estimated as promising selection criteria for identifying superior lines for earliness and high seed yield, including resistance against prevailing stresses (ascochyta blight, botrytis gray mold, dry root rot, and fusarium wilt). The superior derivatives carrying putative characters could be recommended for further breeding and selection of genetic materials for developing suitable genotypes.

Novel Genomic Regions Linked to Ascochyta Blight Resistance in Two Differentially Resistant Cultivars of Chickpea.

Ascochyta blight (AB), caused by the fungal pathogen Ascochyta rabiei, is a devastating foliar disease of chickpea (Cicer arietinum L.). The genotyping-by-sequencing (GBS)-based approach was deployed for mapping QTLs associated with AB resistance in chickpea in two recombinant inbred line populations derived from two crosses (AB3279 derived from ILC 1929 × ILC 3279 and AB482 derived from ILC 1929 × ILC 482) and tested in six different environments. Twenty-one different genomic regions linked to AB resistance were identified in regions CalG02 and CalG04 in both populations AB3279 and AB482. These regions contain 1,118 SNPs significantly associated with AB resistance (p ≤ 0.001), which explained 11.2-39.3% of the phenotypic variation (PVE). Nine of the AB resistance-associated genomic regions were newly detected in this study, while twelve regions were known from previous AB studies. The proposed physical map narrows down AB resistance to consistent genomic regions identified across different environments. Gene ontology (GO) assigned these QTLs to 319 genes, many of which were associated with stress and disease resistance, and with most important genes belonging to resistance gene families such as leucine-rich repeat (LRR) and transcription factor families. Our results indicate that the flowering-associated gene GIGANTEA is a possible key factor in AB resistance in chickpea. The results have identified AB resistance-associated regions on the physical genetic map of chickpea and allowed for the identification of associated markers that will help in breeding of AB-resistant varieties.

Molecular mapping of quantitative trait loci for ascochyta blight and botrytis grey mould resistance in an inter-specific cross in chickpea (Cicer arietinum L.) using genotyping by sequencing.

Ascochyta blight (AB) and botrytis grey mould (BGM) are the most devastating fungal diseases of chickpea worldwide. The wild relative of chickpea, C. reticulatum acc. ILWC 292 was found resistant to BGM whereas, GPF2 (Cicer arietinum L.) is resistant to AB. A total of 187 F8 Recombinant Inbred Lines (RILs) developed from an inter-specific cross of GPF2 × C. reticulatum acc. ILWC 292 were used to identify quantitative trait loci (QTLs) responsible for resistance to AB and BGM. RILs along with parents were evaluated under artificial epiphytotic field/laboratory conditions for two years. Highly significant differences (P < 0.001) were observed for reaction to both pathogens in both years. Parents and RILs were genotyped-by-sequencing to identify genome wide single nucleotide polymorphism (SNPs). A total of 1365 filtered and parental polymorphic SNPs were used for linkage map construction, of which, 673 SNPs were arranged on eight linkage groups. Composite interval mapping revealed three QTLs for AB and four QTLs for BGM resistance. Out of which, two QTLs for AB and three QTLs for BGM were consistent in both years. These QTLs can be targeted for further fine mapping for deployment of resistance to AB and BGM in elite chickpea cultivars using marker-assisted-selection.

Identification of novel resistant sources for ascochyta blight (Ascochyta rabiei) in chickpea.

Chickpea (Cicer arietinum L.) is the second largest pulse crop grown worldwide and ascochyta blight caused by Ascochyta rabiei (Pass.) Labr. is the most devastating disease of the crop in all chickpea growing areas across the continents. The pathogen A. rabiei is highly variable. The resistant sources available are not sufficient and new sources needs to be identified from time to time as resistance breakdown in existing chickpea varieties is very frequent due to fast evolution of new pathotypes of the pathogen. Therefore, this work was undertaken to evaluate the existing chickpea germplasm diversity conserved in Indian National Genebank against the disease under artificial epiphytotic conditions. An artificial standard inoculation procedure was followed for uniform spread of the pathogen. During the last five winter seasons from 2014-15 to 2018-19, a total of 1,970 accessions have been screened against the disease and promising accessions were identified and validated. Screening has resulted in identification of some promising chickpea accessions such as IC275447, IC117744, EC267301, IC248147 and EC220109 which have shown the disease resistance (disease severity score ≤3) in multiple seasons and locations. Promising accessions can serve as the potential donors in chickpea improvement programs. The frequency of resistant and moderately resistant type accessions was comparatively higher in accessions originated from Southwest Asian countries particularly Iran and Syria than the accessions originated from Indian sub-continent. Further large scale screening of chickpea germplasm originated from Southwest Asia may result in identifying new resistant sources for the disease.

Introgression of productivity enhancing traits, resistance to pod borer and Phytopthora stem blight from Cajanus scarabaeoides to cultivated pigeonpea.

The study aimed at introgression of productivity enhancing traits and resistance to pod borer and Phytophthora stem blight from wild to cultivated pigeonpea through an inter-specific cross between Cajanus scarabaeoides (ICP 15683) and C. cajan (ICPL 20329). Progenies derived from the direct segregating (without backcross) population and backcross population were evaluated for yield and yield contributing traits namely fruiting branches and pods plant-1 and 100-seed weight. Introgressed progenies having higher fruiting branches, pods and yield plant-1 compared to the cultivated parent were identified in both populations. A few progenies with significantly shorter plant height, early flowering and early maturity as compared to both cultivated and wild parents were also recovered in both populations. Progenies from both the populations were identified with higher resistance to pod borer and Phytophthora stem blight. However, some introgressed progenies having lower seed weight and seeds per pod were also recovered. The promising progenies are currently being used in the breeding programme to develop cultivars with improved productivity and resistance to pod borer and Phytophthora stem blight.