Papaya is widely grown in tropical and subtropical climates due to its high yield potential and high returns. The vital hormone melatonin, regulating various biological processes in plants, is eco-friendly and less harmful to humans than other chemicals. This study aims to enhance the quality and antioxidant enzyme activities and lessen postharvest senescence in papaya cv. CO 8 fruits during both ambient (32 ± 2 °C and 55 ± 5% RH) and cold storage (10 ± 2 °C and 90–95% RH) as exogenous melatonin (EMT) is applied in varying concentrations. An optimum melatonin dose of 1.5 mM was applied as a pre-harvest spray 15 days before harvest and a postharvest dip proved effective in prolonging shelf life (under ambient it prolonged to day 9 and under cold storage up to 28 days) and delaying ripening and softening. Exogenous melatonin application enhanced antioxidant activity, reduced weight loss, maintained firmness, delayed ripening enzymes, and lowered ethylene and CO₂ levels. For instance, control fruits had weight losses between 7.42% and 10.09%, while fruits treated with 1.5 mM melatonin showed 5.74% and 9.06% weight loss under ambient and cold storage, respectively. In conclusion, applying EMT (1.5 mM) could be an economically viable and environmentally benign way to lessen senescence after harvest and preserve the qualities of the papaya fruit during ambient and cold storage.

Tomato (Solanum lycopersicum), a solanaceous crop, is widely cultivated worldwide. This study evaluates the impact of Nano DAP (diammonium phosphate) on morpho-physiological traits, biochemical properties, yield, and quality parameters. Eight treatments comprising varying proportions of DAP and Nano DAP were evaluated for traits including plant height, leaf area, chlorophyll index, total dry matter production, gas exchange parameters, leaf soluble protein, total soluble solids (TSS), ascorbic acid, titratable acidity, firmness and fruit yield. The hybrid tomato variety 'Shivam' was cultivated in pot culture under a glasshouse at Tamil Nadu Agricultural University, Coimbatore, using a completely randomized design with five replications. Foliar sprays with different proportions of nano DAP and DAP were applied 30 and 45 days after transplanting. Among the treatments, 75% RDNP (recommended nitrogen and phosphorus dose) combined with two foliar sprays of nano DAP @ 0.7% (T5) significantly increased plant height (48.90 cm and 54.31 cm), chlorophyll index (40.05 and 42.15), dry matter production (55.45 g plant?¹), TSS (5.52 Brix), fruit production, and ascorbic acid content. This treatment also improved gas exchange parameters, fruit firmness, and overall `growth and productivity compared to other treatments. Conversely, the absolute control group demonstrated the lowest performance across all parameters. The study highlights that combining both conventional fertilizers with Nano DAP considerably improves tomato growth by enhancing nutrient absorption, particularly nitrogen and phosphorus, which are essential for cell division, photosynthesis, and energy transfer. Nano DAP, due to its small particle size and large surface area, effectively penetrates plant tissues, increasing nutrient availability, chlorophyll content, and plant height. These findings underscore the potential of Nano DAP to substantially enhance tomato yield and quality, thereby contributing to sustainable crop production.

Dragon fruit, or pitaya, has become famous owing to its unique look, health advantages, and resilience to diverse climates, rendering it especially appropriate for Southern India. This study investigates the economic feasibility and production challenges of dragon fruit farming in Andhra Pradesh, Karnataka, and Tamil Nadu in 2024. Financial assessments using Net Present Value (NPV), Benefit-Cost Ratio (BCR), and Internal Rate of Return (IRR) indicate that dragon fruit farming is profitable in these states, with Andhra Pradesh and Karnataka showing better financial outcomes compared to Tamil Nadu. Garrett's Ranking Technique was employed to identify and rank the production and marketing constraints. Key production challenges in Tamil Nadu and Andhra Pradesh include the high cost of installation materials and insufficient technical support, while Karnataka primarily faces a shortage of skilled labor. On the marketing front, the absence of adequate cold storage facilities and high transportation costs pose significant hurdles across all states. The findings highlight the need for targeted solutions, such as improving access to affordable installation materials, upgrading cold-storage infrastructure, and implementing training programs for farmers. Addressing these challenges can enhance the profitability and sustainability of the dragon fruit industry in Southern India.

The effects of melatonin, salicylic acid (SA) and brassinosteroids on the post-harvest quality and shelf life of two mango varieties, Alphonso and Sindhura, were investigated with respect to physiological, biochemical and enzymatic changes. The study assessed physiological loss in weight (PLW), Total Soluble Solids (TSS), titratable acidity, sugars, total phenolics, carotenoids, ripening related enzymes (pectin methylesterase, polygalacturonase, amylase and cellulase) and antioxidant enzymes (peroxidase, catalase and superoxide dismutase). According to the results, the shelf life of mango was considerably increased by 200 µM melatonin, 2.0 mM salicylic acid and 25 ppm brassinosteroids, which also decreased PLW to 9.81 %, 10.12 % and 9.79 % in Alphonso and 9.48 %, 9.51 % and 9.92 % in Sindhura. These treatments maintained a balance between TSS, sugars and acidity, while preserving higher concentration of total phenolics and carotenoids. Treated fruits exhibited lower ripening enzyme activity, particularly polygalacturonase, which declined by 16.7 %, 11.2 % and 17.0 % in Alphonso and 11.5 %, 10.9 % and 11.2 % in Sindhura with 200 µM melatonin, 2.0 mM salicylic acid and 25 ppm brassinosteroids treatments respectively. Similarly, pectin methyl esterase (PME) was reduced by 12.2 %, 11.6 % and 10.5 % in Alphonso and 12.1 %, 10.3 % and 12.1 % in Sindhura corresponding to these treatments, delaying cell wall degradation and maintaining fruit firmness. Additionally, antioxidant enzymes were upregulated, mitigating oxidative stress by reducing reactive oxygen species (ROS) and preserving fruit quality. These treatments were effective in delaying ripening, enhancing stress resistance and extending the marketability of mangoes during storage. This study highlights the potential of melatonin, salicylic acid and brassinosteroids as eco-friendly alternatives to synthetic chemicals for improving post-harvest mango management.

Aims: To study the effect of nutrients and plant growth regulators through foliar spray on yield and quality characteristics of guava var. Arka Kiran. Study design: Randomized Block Design (RBD). Place and Duration of Study: The experimental trial was conducted at a Farmer’s field in Theethipalayam village of Coimbatore district, Tamil Nadu during 2022-2023. Methodology: The current study included six treatments and three replications. Three-year-old guava trees with uniform size, growth, and bearing habit were chosen for imposing treatments. Observations on fruit yield, physical and quality characteristics of guava were recorded. Results: Fruit diameter (6.30 cm), Fruit weight (168.17 g), fruit volume (146.46 ml), fruit yield (16.53 kg/tree) and the number of fruits per tree (98.35) were recorded maximum in plants treated with nutri-hormonal spray-I. The best-quality fruits in terms of increased TSS (12.08), ascorbic acid (185.35 mg/g), reducing (3.15%), non-reducing (4.19%), and total sugars (7.35%) and reduced acidity (0.40%) were also recorded in the same combination. Conclusion: The foliar application of nutrients and PGRs spray-I can be advocated to improve the yield and quality attributes of guava.