Effect of Sodium Doping on Thermal Properties of Perovskite RMnO3 for Potential Magnetoelectric Applications

The partial replacement of rare earth cation by sodium introduces large size and charge mismatch at A-site affecting the bulk modulus and thermal properties of RMnO3 which in turn makes them suitable candidates for thermoelectric applications. Thermal, elastic, cohesive properties of sodium doped Rare Earth manganites R1-xNaxMnO3 (R3+= La, Pr, Tb) has been studied by means of a Modified Rigid Ion Model (MRIM) and AIM theory. Lattice specific heat (Cp) of Pr0.8Na0.2MnO3, and Tb0.85Na0.15MnO3 as a function of temperature (1K£T£ 350K) is found to be in agreement with the published data. The trend of variation of Debye temperature (?D), thermal expansion (?), bulk modulus (B) and cohesive energy (?) with A-site cationic radius is predicted probably for the first time for these technologically important doped rare earth manganites. Keywords: Thermal Expansion, Specific Heat, Thermal properties, Colossal Magnetoresistance Materials, Magnetoelectric materials

Thermodynamic Properties of Ni-substituted LnCoO3 Perovskite

With the objective of exploring the unknown thermodynamic properties of Ni-substituted LnCoO3 perovskite, we present here an investigation of the temperature-dependent (10K < T < 300K) specific heat of LnCo0.95Ni0.05O3 (Ln=Pr and Nd) family. We report here probably for the first time the specific heat along with other elastic and thermal properties of Ni doped perovskite cobaltate LnCoO3 (Ln=Pr and Nd). In addition, the results on the cohesive energy (f) in orthorhombic perovskite phase, molecular force constant (ƒ), Reststrahlen frequency (uo) and Gruneisen parameter (γ) are also presented. Keywords: Specific heat, Bulk modulus, Perovskite cobaltat

Cohesive and thermoelastic properties of 〖(KCN)〗_(x ) 〖(KCl)〗_(1-x)

The thermal and elastic properties of are investigated by means of Extended Three Body Force Shell Model (ETSM). The motion of constituent atoms or molecules or the nature of binding forces of a crystal can be investigated by exploring the mechanical properties of pure and mixed crystals like anharmonic elastic properties. We have chosen different compositions at different temperature to show that anharmonic elastic properties are temperature dependent rather than composition dependent and the purpose of study is to test the mechanical stabilities of the potential. Moreover, the thermodynamic properties such as molecular force constant (f), Reststrahlen frequency (uo), cohesive energy (f), Debye temperature (θD) and Gruneisen parameter (γ) have also been discussed. Keywords: Elastic constants, Cohesive energy, Thermodynamic propertie

Resistance Evaluation for Native Potato Accessions against Late Blight Disease and Potato Cyst Nematodes by Molecular Markers and Phenotypic Screening in India

The potato originated in southern Peru and north-western Bolivia (South America). However, native accessions have also been cultivated in India for many years. Late blight, caused by the fungus Phytophthora infestans, is the most devastating potato disease, while potato cyst nematode (Globodera spp.) (PCN) is another economically significant quarantine-requiring pest in India. In this study, we have generated a new Indian native collection of 94 potato accessions collected from different parts India. These accessions were screened against late blight and potato cyst nematode resistance by using gene-based molecular markers and phenotypic screening methods. Marker assisted selection using R1 gene-specific marker CosA210 revealed a late blight resistance gene in 11 accessions. PCN resistance bands were found in 3 accessions with marker TG689141, 5 accessions with marker 57R452, and 1 accession having Gro1-4-1602 marker for G. rostochiensis (Ro1,4), while 64 accessions amplified marker HC276 indicating G. pallida (Pa2,3) resistance gene (GpaVvrn QTL). On the other hand, phenotypic screening against late blight resistance under natural epiphytic conditions (hot-spot) revealed three accessions with high resistance, while others were resistant (1 accession), moderately resistant (5 accessions), susceptible (29 accessions), and highly susceptible (56 accessions). For G. rostochiensis (golden cyst nematode) and G. pallida (white cyst nematode) resistance, accessions were grouped into highly resistant (3, 3), resistant (0, 2), moderately resistant (6, 29), susceptible (32, 30), and highly susceptible (53, 30), respectively, for the two PCN species. Collectively, we identified promising accessions with high resistance to late blight (JG-1, Kanpuria Safed, and Rangpuria), and also highly resistant to both Globodera species (Garlentic, Jeevan Jyoti, and JG-1). Our findings suggested that these accessions would be useful for late blight and PCN resistance breeding, as well as future molecular studies in potatoes

Table_1_Root system architecture for abiotic stress tolerance in potato: Lessons from plants.DOCX

The root is an important plant organ, which uptakes nutrients and water from the soil, and provides anchorage for the plant. Abiotic stresses like heat, drought, nutrients, salinity, and cold are the major problems of potato cultivation. Substantial research advances have been achieved in cereals and model plants on root system architecture (RSA), and so root ideotype (e.g., maize) have been developed for efficient nutrient capture to enhance nutrient use efficiency along with genes regulating root architecture in plants. However, limited work is available on potatoes, with a few illustrations on root morphology in drought and nitrogen stress. The role of root architecture in potatoes has been investigated to some extent under heat, drought, and nitrogen stresses. Hence, this mini-review aims to update knowledge and prospects of strengthening RSA research by applying multi-disciplinary physiological, biochemical, and molecular approaches to abiotic stress tolerance to potatoes with lessons learned from model plants, cereals, and other plants.</p