Breeding Mechanisms for High Temperature Tolerance in Crop Plants

Increase in global warming poses a severe threat on agricultural production thereby affecting food security. A drastic reduction in yield at elevated temperature is a resultant of several agro-morphological, physiological and biochemical modifications in plants. Heat tolerance is a complex mechanism under polygenic inheritance. Development of tolerant genotypes suited to heat extremes will be more advantageous to tropical and sub tropical regimes. A clear understanding on heat tolerance mechanism is needed for bringing trait based improvement in a crop species. Heat tolerance is often correlated with undesirable traits which limits the economic yield. In addition, high environmental interactions coupled with poor phenotyping techniques limit the progress of breeding programme. Recent advances in molecular technique led to precise introgression of thermo-tolerant genes into elite genetic background which has been reviewed briefly in this chapter

Development and certification of chromic acid-free anodizing process for aircraft grade aluminium alloys

21-27Chromic acid (Cr6+) anodization process is widely used for the corrosion protection of aircraft aluminium alloys. Hexavalent chromium being toxic in nature need to be phased out by eco-friendly alternatives. In the present study modified tartaric-sulphuric acid (TSA) process has been developed followed by sealing in permanganate based bath to obtain 4 to 6 µm thick anodic oxide layer on 2024-T3, 6061-T6 and 7075-T6 aluminium alloys. The process was carried out using a pilot scale anodizing plant. The anodized specimens were characterized for visual observation, thickness, adhesion, electrical breakdown voltage, corrosion resistance and tensile behaviour. All the tests were carried out as per MIL-A-8625F specifications. The specimens were also subjected for about 800 hrs to real time corrosion testing, 200 metres away from sea shore at Mandapam Camp, Rameshwaram, India. The performance of the permanganate sealed TSA anodized aluminium alloys are comparable with that of the conventional chromic acid anodized coatings. This chromic acid-free anodization process has been qualified to airworthiness regulating standards by Indian military certification authorities. Efforts are in progress to commercialize this technology for use on aero platforms

Development and certification of chromic acid-free anodizing process for aircraft grade aluminium alloys

Chromic acid (Cr6+) anodization process is widely used for the corrosion protection of aircraft aluminium alloys. Hexavalent chromium being toxic in nature need to be phased out by eco-friendly alternatives. In the present study modified tartaric-sulphuric acid (TSA) process has been developed followed by sealing in permanganate based bath to obtain 4 to 6 µm thick anodic oxide layer on 2024-T3, 6061-T6 and 7075-T6 aluminium alloys. The process was carried out using a pilot scale anodizing plant. The anodized specimens were characterized for visual observation, thickness, adhesion, electrical breakdown voltage, corrosion resistance and tensile behaviour. All the tests were carried out as per MIL-A-8625F specifications. The specimens were also subjected for about 800 hrs to real time corrosion testing, 200 metres away from sea shore at Mandapam Camp, Rameshwaram, India. The performance of the permanganate sealed TSA anodized aluminium alloys are comparable with that of the conventional chromic acid anodized coatings. This chromic acid-free anodization process has been qualified to airworthiness regulating standards by Indian military certification authorities. Efforts are in progress to commercialize this technology for use on aero platforms

Speed Breeding: A Propitious Technique for Accelerated Crop Improvement

Development of climate-resilient genotypes with high agronomic value through conventional breeding consumes longer time duration. Speed breeding strategy involves rapid generation advancement that results in faster release of superior varieties. In this approach, the experimental crop is grown in a controlled environment (growth chambers) with manipulation provisions for temperature, photoperiod, light intensity, and moisture. The generation of the crop cycle can be hastened by inducing changes in the physiological process such as photosynthesis rate, flowering initiation, and duration. Speed breeding eases multiple trait improvement in a shorter span by integration of high-throughput phenotyping techniques with genotype platforms. The crop breeding cycle is also shortened by the implementation of selection methods such as single-seed descent, single plant selection, and marker-assisted selection

Simplified detection of the hybridized DNA using a graphene field effect transistor

<p>Detection of disease-related gene expression by DNA hybridization is a useful diagnostic method. In this study a monolayer graphene field effect transistor (GFET) was fabricated for the detection of a particular single-stranded DNA (target DNA). The probe DNA, which is a single-stranded DNA with a complementary nucleotide sequence, was directly immobilized onto the graphene surface without any linker. The V_Dirac was shifted to the negative direction in the probe DNA immobilization. A further shift of V_Dirac in the negative direction was observed when the target DNA was applied to GFET, but no shift was observed upon the application of non-complementary mismatched DNA. Direct immobilization of double-stranded DNA onto the graphene surface also shifted the V_Dirac in the negative direction to the same extent as that of the shift induced by the immobilization of probe DNA and following target DNA application. These results suggest that the further shift of V_Dirac after application of the target DNA to the GFET was caused by the hybridization between the probe DNA and target DNA.</p

Facile Synthesis of Hafnium Oxide Nanoparticle Decorated on Graphene Nanosheet and Its Photocatalytic Degradation of Organic Pollutants under UV-Light Irradiation

The HfO2 nanoparticles and the nanocomposites of HfO2-graphene (10, 30, and 50 wt%) were prepared via precipitation and simple mixing method. The XRD pattern confirmed the presence of monoclinic HfO2 and hexagonal graphene in the nanocomposite. Raman spectroscopy studies revealed the formation of HfO2-graphene nanocomposite. According to SEM and TEM images the HfO2, NPs are spherical, and their size is less than 10 nm, anchored on the surface of the graphene sheets. The EDX spectrum shows carbon, oxygen, and HfO2 and reveals the formation of the HfO2-graphene nanocomposite. The UV-vis absorption spectra show the optical properties of synthesized HfO2-graphene nanocomposite. The study examines the influence of different ratios of the addition of graphene on the photocatalytic activity of HfO2-graphene. It was found that the HfO2-graphene (50 wt%) 40 mg nanocomposite exhibits enhanced photocatalytic activity than the bare HfO2 towards the methylene blue photodegradation, an aromatic pollutant in water under UV light irradiation, which can be applied optimally for individually wastewater management system. The HfO2-graphene (50 wt%) photocatalyst degrades 81 ± 2% of tetracycline in 180 min, implying that tetracycline can be degraded more efficiently under UV light. The enhancement in photocatalytic activity under UV light illumination can be attributed to the effective separation of photogenerated electrons, inhibiting recombination in the HfO2-graphene composite

Influence of <i>Eucalyptus</i> Agroforestry on Crop Yields, Soil Properties, and System Economics in Southern Regions of India

Agroforestry benefits farmers, making it a sustainable alternative to monoculture. To create a viable Eucalyptus clone-based agroforestry system, a field experiment was carried out in Tamil Nadu, India. The economics and changes in the soil qualities were evaluated by growing agricultural and horticultural crops, namely pearl millet, sorghum, maize, sesame, small onions, green gram, and red gram, as intercrops under eight-month-old eucalyptus clone trees using a randomised block design in three replications at a spacing of 3 m × 1.5 m. The plots for the intercrops and the eucalyptus clones were kept apart for comparison. Maize showed the greatest drop in plant height during all the phases, including 30 DAS, 60 DAS, and harvest, while small onions showed the least reduction in plant height. Sesame and small onions showed the greatest drop in dry matter production, whereas sorghum showed the least. In terms of the intercrop yield reduction, maize had the biggest reduction and green gram had the lowest. Red gram had the largest crop equivalent yield, whereas maize had the lowest. The volume of the trees was generally increased more favourably by red gram than by green gram. The intercrops had some effects on the nutrients in the soil. Red gram intercropping had the highest levels of EC, soil organic carbon, available soil nitrogen, available soil phosphorus, and available soil potassium, while the sole tree treatment had the lowest levels. Small onions, red gram, and sesame were the crops; tree + small onion, tree + red gram, and tree + sesame were the intercrop combinations with the highest gross income, net income, and B:C in the intercropping treatment alone. Tree + green gram had the highest land equivalent ratio (LER) and the red gram, sesame, and small onion intercrops were shown to be the most profitable. Although the present study supports a complementary relationship, the lack of awareness among farmers of Eucalyptus allelopathy formed the major limitation