14 research outputs found

    Evaluating the seasonal accumulation of Heat units as an agroclimatic indicator on Baby corn (Zea mays L.) under different sowing windows

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    Temperature determines the plant's growth and development, which decides the onset of different phenophasic stages of the Baby corn. This study aimed to evaluate the phenological behaviour and yield of Baby corn (Zea mays L.) influenced by sowing windows and heat units with the field investigations carried out during winter (January – April) and kharif  (June – September) 2022 at Eastern Block Farm of Tamil Nadu Agricultural University, Coimbatore. Growing Degree Days (GDD), Photo Thermal Units (PTU), Helio Thermal Units (HTU), Relative Temperature Disparity (RTD), Heat Unit Efficiency (HUE) and seasonal efficiency were calculated at different phenological stages. The results revealed that early attainment of phenophases was noticed during winter (62.5 days - January 21st to 27th April) than kharif (77.1 days – 15th June to 4th October). Among seasons, higher accumulation of GDD (1553) and PTU (19099) was observed during kharif 2022, whereas maximum accumulation of HTU (9923) and RTD (2146) was observed in winter 2022. Seasonal efficiency was higher during kharif (118) than during the winter season (81). The sowing windows significantly influenced the higher accumulation of heat units and yield attributes. Hence, higher yield (11922.7 kg ha-1) and HUE (7.3) were obtained during kharif than in winter 2022 (yield – 7849 kg ha-1 and HUE – 5.8). Weather parameters showed a negative correlation except RH-I, WS, SR and HUE during winter 2022 (R2=0.802) and RH-II, WS, RF, Daylength, HUE during kharif 2022, which had a positive correlation (R2=0.795). Baby corn is highly sensitive to increasing temperature. Hence, the study expresses the effect of varying ambient temperature on the duration between the phenological stages and yield.  

    Light interception and radiation use efficiency (RUE) in maize (Zea mays. L) intercropping with greengram (Vigna radiata L.)

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    Intercropping is growing two or more crop species simultaneously, different canopy architectures by row configuration, changing light interception, radiation utilisation, and increased yield. The present study aimed to evaluate different intercropping systems affected light interception per cent and radiation use efficiency in maize (Zea mays L.) intercropping with greengram (Vigna radiata L.) different ratios. Field experiments were conducted for Kharif 2022 and Rabi 2022-2023 seasons, which were laid out in a split-plot design and replicated three times. Three Nitrogen levels viz., N1 - 75 % RDN (Recommended dose of Nitrogen), N2 – 100% RDN, N3-125% RDN had taken as the main plot and three intercropping treatments were taken as subplot viz., M2G2- replacement series (two row of maize and two row of Greengram), M4G2- replacement series (four rows of maize and two row of Greengram), M2G3-paired row system (two rows of maize and three rows of Greengram), and sole maize. Both light interception and radiation use efficiency were significantly affected by intercropping systems. Light interception per cent of the main crop (maize) was significantly higher (69.0, 75.5 and 71.0 % during Kharif and 60.1, 78.1 and 76.6 during rabi) at vegetative, flowering and maturity phases, respectively. The Kharif 2022 and Rabi 2022-2023 maximum Radiation Use Efficiency (RUE) of Maize intercropping with green gram (maize + greengram) was higher in T12 (M2G3 paired row with 125 % Recommended Dose of Nitrogen) recorded as 2.46 (Kharif) and 1.43 (rabi). The outcome might be utilised to optimise the row configuration of intercropping design, explain the mechanism of intercropping on light utilisation, and improve radiation use efficiency

    Exogenous melatonin improves seed germination and seedling growth in greengram under drought stress

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    Drought stress diminishes seedling germination and vigor by reducing water uptake, inhibiting plant growth and development. Most of the pulse growing areas are under rainfed ecosystems, which significantly reduces crop yield. Melatonin, a growth-regulating compound, is widely used to mitigate the negative effects of abiotic stresses in pulses. With this background, a laboratory experiment was conducted to standardize the optimum melatonin concentration for seed treatment and foliar application in greengram, to minimize the ill effects of drought stress. The experiment was arranged in a completely randomized design (CRD) with three replications for each treatment. The treatments consisted of soaking seeds with different melatonin concentrations, viz., 20, 40, 60, 80 and 100 μM. Seeds were sown in a perti dishes and the drought stress was imposed using poly ethylene glycol 6000 (PEG 6000) @ - 0.4 MPa, and plates were maintained at room temperature (24-30 °C). After the seedlings emerged, various seedling growth parameters like germination percentage, shoot length, root length, vigor index, promptness index, germination stress tolerance index, fresh and dry weight of the seedlings, plant height stress index and root length stress index were recorded. The experimental results showed that drought stress significantly reduced germination percentage and other growth-related parameters in greengram seedlings compared to the melatonin treatments. Among the melatonin treatments, seeds treated with @ 100 μM concentration recorded the highest germination percentage (99.67 %), promptness index (98.80), vigour index (1631.68), shoot and root length (8.9 cm and 7.5 cm), fresh and dry weight of the seedlings (3.249 and 0.147 mg seedling-1) under PEG induced drought stress condition

    Melatonin mediated high-temperature tolerance at seedling stage in green gram (Vigna radiata L.)

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    Global warming is predicted to have a generally negative effect on food grain production. The emergence of seedlings, blooming, pod-filling stages and yield of the mung bean are affected by high-temperature stress. Melatonin is a multifunctional signaling molecule with antioxidant properties that plays a vital role in plant stress defense mechanism. With this knowledge, the experiment was conducted to identify the optimum melatonin concentration to mitigate the adverse effects of high temperature in green gram var CO 8 with a completely randomized design (CRD). The treatments consisted of soaking seeds with different melatonin concentrations, viz., 20, 40, 60, 80 and 100 μM. Seeds were sown in a pertidish and allowed to germinate. After 5 days, the seedlings were exposed to two different high-temperature stress following the temperature induction response (TIR) protocol in the growth chamber viz., Ambient + 2°C (40°C) and Ambient + 4°C (42°C). After stress period, the seedlings were allowed to recover at room temperature for 2 days. At the end of the recovery period, observations on temperature tolerance-related traits viz., survival percentage, per cent reduction of shoot and root growth, cell viability, mortality per cent, malondialdehyde content, superoxide dismutase and catalase activity of green gram seedlings were assessed. Seeds pre-treated with melatonin of 100 and 80 µM exhibited higher survival percentage, shoot and root growth, cell viability and antioxidant enzyme activity (like superoxide dismutase and catalase) with reduced mortality per cent and malondialdehyde content under high-temperature stress at both 40°C and 42°C. The results revealed that seeds treated with different melatonin concentrations significantly improved green gram germination and seedling health.               

    Evaluation on the development of soil fertility gradients with nutrient exhaustive crop (Sorghum bicolor) regard to N, P, and K in Inceptisols in semi-arid regions of Tamil Nadu

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    Soil test crop response (STCR's) soil fertility gradient approach is based on the idea that  complex treatments are superimposed in a field to obtain crop responses for correlating with soil test values that are artificially created by differential fertiliser treatments prior to conducting the regular experiment, thereby providing a scientific basis for balanced fertilisation between applied and available forms of nutrients. The present study aimed to develop the fertility gradient with sorghum as test crop in the field concerning N, P, and K and also to evaluate its impact on sorghum nutrient uptake, and soil fertility. The experimental field was split into three equal strips. Strips I, II, and III each received three graded levels of fertiliser N (nitrogen), P2O5 (phosphorus pentoxide), and K2O (potassium oxide) as urea, single super phosphate, and muriate of potash, respectively. The green fodder yield of sorghum recorded at harvest in strip I, II & III was 16.4, 23.4 and 28.2 t ha-1, respectively. Whereas post-harvest soil available nitrogen in strip I, II & III was 155, 190 & 214 kg ha-1 respectively, for available phosphorus 12.5, 23.2 & 31.8 kg ha-1 respectively and for available potassium it is 332, 370 & 396 kg ha-1 respectively. Wide variations in green fodder yield and soil fertility were observed among the strips, establishing the influence of graded amounts of fertiliser treatment on these parameters and the formation of a soil fertility gradient

    Influence of the downwash airflow in Hexacopter Drone on the spray distribution pattern of boom sprayer

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    The spray characteristics of drone sprayers are significantly influenced by the downwash airflow produced by Drone multi-rotors. The present study aimed to study the influence of downwash airflow and the operational parameters of Drone sprayer, viz., flight height, travel speed, rotor configuration, payload and wind velocity on the spray distribution pattern for boom sprayer attachment to Drone. The boom type sprayer consisted of four numbers of flat fan nozzles placed at three different spacing viz., 30, 45 and 60 cm between each nozzle. The spray distribution pattern of the Hexacopter Drone was studied at three different operating pressures, viz., 3.0, 4.0 and 5.0 kg cm-2. A spray patternator of 5 m x 5 m was developed per the Bureau of Indian Standards (BIS) standard to study the spray uniformity of volume distribution pattern. The best spray uniformity was found as 0.37 % CV value at 60 cm nozzle spacing and 4 kg cm-2 operating pressure. The optimised parameters viz., 60 cm of nozzle spacing and 4 kg cm-2 operating pressure, the influence of downwash airflow on the spray volume distribution of hexacopter Drone with boom spray attachment were studied. The Drone hovered at three different heights, viz., 1.0, 2.0 and 3.0 m from the top of the patternator and spray operating pressure was maintained at 4 kg cm-2. It was observed that less volume of spray was collected at the middle portion when the Unmanned Aerial Vehicle (UAV) was hovered at 1.0 m height due to the direct impact of downwash airflow of rotors. The uniform spray volume distribution pattern was observed when Drone hovered from 1.0 m to 3.0 m height. A round vertex pattern of spray pattern was generated with boom type nozzles configuration due to the direct impact of downwash airflow of rotors. This study will be helpful in the configuration of nozzles attached to the drone sprayers, optimization of spray operational parameters, and revealing spray volume distribution pattern

    Assessing antioxidant system and yield of maize (Zea mays L.) inbreds under elevated temperature condition

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    Maize (Zea mays L.) is the most important food and feed crop grown under diverse soil and climatic conditions. Among the cereals, demand for maize is increasing year after year, but fluctuation in climatic conditions especially the temperature extremes is the current and future threat in maize cultivation. Each degree Celsius increase in global mean temperature causes yield reduction up to 7.4 per cent in maize. The high temperature stress impact at the reproductive stage affects grain filling rate and duration. Adaptation of maize crop to future warmer climatic conditions requires a better understanding of physiological responses to elevated temperatures. With this view, a pot culture experiment was conducted at the Department of Crop Physiology, TNAU, Coimbatore during the summer season of 2020. Two maize inbreds viz., UMI 1230 and CBM-DL- 322 were taken for the study and exposed to high temperature stress treatments viz., T1 - ambient, T2 - ambient+4°C and T3 - ambient+6°C (44°C) for 10 days during the reproductive stage to assess the changes in biochemical and yield traits. The ambient+4ºC treatment revealed that the maize inbred line CBM-DL-322 recorded lower malondialdehyde content with over production of antioxidant enzyme activity (superoxide dismutase, catalase and ascorbate peroxidase). Cob weight and seed set parentage showed a negative correlation with both elevated temperatures. It is concluded that the maize inbreds line CBM-DL- 322 performed better at an elevated temperature at ambient+4°C and recorded more cob weight (57.09g) compared to UMI 1230 inbred (43.56g)

    Framework and Overview of a State-Wide College Mental Health Program in Kerala, India

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    Background: Mental health issues are common among college students, and structured services have been proven to enhance outcomes. Despite increased enrolment for higher education in India, college mental health services remain sparse. JEEVANI is the first structured state-wide college mental health service in India. This paper describes its framework and provides an overview of its functioning during the initial five months. Methods: In 2019–2020, the Directorate of Collegiate Education, Government of Kerala, implemented the program in 66 colleges catering to approximately 60,000 students. Qualified counsellors were trained to identify issues and provide interventions and early referrals, using a stepped-care approach. They conducted awareness programs to promote mental health and reduce stigma. Results: The services were accessed by 2,315 students during the assessment period (October 2019 to February 2020). The beneficiaries were predominantly females (54.1%). Over a third (38.8%) belonged to the lower socio-economic strata, and 2.5% had significant vulnerabilities. Although no syndromal diagnoses were made, anxiety and depression were the most common presentations. The counsellors provided 3,758 individual sessions and facilitated support for students who reported academic difficulties or interpersonal issues. Severe mental illness was detected in 54 students, and referrals for specialist mental health input were initiated in 68. Conclusion: Describing the framework, sharing the technical material, and providing an overview of its functioning from a resource-constrained setting in India may encourage higher education institutions in low- and middle-income countries to consider similar projects

    Melatonin Decreases Negative Effects of Combined Drought and High Temperature Stresses through Enhanced Antioxidant Defense System in Tomato Leaves

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    In tomato (Lycopersicon esculentum L.), the effects of combined drought (D) and high temperature (HT) stress during the flowering stage had not been studied in detail. Therefore, this study was conducted with an objective of quantifying the effects of foliar spray of melatonin under individual and combined drought and HT stress. At flowering stage, D stress was imposed through withholding irrigation, while HT stress was imposed through exposing the plants to ambient temperature (AT) along with an increase of +5 °C. Under D + HT, plants were first subjected to drought followed by a + 5 °C increase in AT. The duration of individual or combined stress was ten days. At 80% available soil moisture, 100 µM melatonin was sprayed on D, HT, or D + HT treated plants. Among the stresses, D + HT stress increased the thylakoid membrane damage and decreased the photosynthetic rate and fruit yield more than D or HT stress. Foliar spray of 100 µM melatonin produced decreased thylakoid membrane damage [D: 31%, HT: 26%, and D + HT: 18%] and increased antioxidant enzyme, viz., superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, and glutathione reductase, activity over stress-control plants. The photosynthetic rate [D: 24%, HT: 22%, and D + HT: 19%] and fruit yield [D: 32%, HT: 23%, and D + HT: 16%] were increased over stress-control plants. Hence, it is evident that the increased photosynthetic rate and fruit yield in D + HT and 100 µM melatonin-sprayed plants may be associated with an increased antioxidant defense system. Melatonin as a novel biostimulator has a great potential in scavenging free radicals through increased antioxidant activity, which shields the photosynthetic membrane from damage and therefore helps in stress mitigation
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