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.

Aims: An experiment was conducted to examine the effect of various concentrations of melatonin on post harvest weight loss and shelf life of three traditional banana varieties viz. Ney Poovan, Nendran and Red Banana. Study Design: Completely Randomized Design. Place and Duration of Study: Post Graduate laboratory, Horticultural College and Research Institute, Tamil Nadu Agricultural University, Coimbatore during 2022. Methodology: Banana hands were dipped in 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 mM melatonin for 15 minutes and were stored at ambient temperature. The hands dipped in water were treated as control. Observations on physiological weight loss and shelf life were recorded till the fruits remained marketable. Results: The results depicted that fruits immersed in 1.0 and 1.5 mM melatonin for 15 minutes recorded lower weight loss (31.56, 30.55 and 24.90%) on 11^th, 11^th and 12^th day of storage and longer shelf life by 3, 2.67 and 2.67 days in Ney Poovan, Nendran and Red Banana respectively. Conclusion: The effects of melatonin were due to its efficiency in reducing transpiration and respiration and thereby lowering weight loss. The lowered metabolic activity not only mitigated weight loss but also maintained firmness and turgidity of the fruits and thereby prolonging the storability. It was evident from the results that melatonin treatment could be a good practice for extending postharvest life of banana by reducing the physiological loss in weight simultaneously maintaining the appearance.

Background: Grape is one of the important cash crops cultivated in India. The grape bunches during growth stages are adversely affected by various biotic and abiotic factors which in turn affects the yield and quality. In addition, high usage of agrochemicals in grape cultivation increased concern over pesticide residues among consumers. Therefore, an alternative technique of fruit bagging to enhance the yield and quality as well as to minimize pest and disease infestation is emphasized. Bagging of grape bunches also aids in preventing the agrochemicals entry into the fruits. Methods: A field experiment was conducted to study the impact of fruit bagging on yield attributes in grape cv. Muscat Hamburg at Coimbatore during winter (August - December, 2018) and summer seasons (January - May, 2019). The grape clusters were covered with non-woven UV stabilized polypropylene bags of different colours viz., blue, white, yellow, red and green immediately after fruit set and were removed before harvest. The unbagged clusters were treated as control. Result: In the present study, the grape clusters covered with white colour non-woven UV stabilized polypropylene bags was found to be superior for yield attributes viz., bunch weight (255.03 g and 294.80 g), berry diameter (15.39 mm and 15.97 mm), berry weight (4.30 g and 4.85 g), pulp weight (3.88 g and 4.44 g), peel weight (0.28 g and 0.31 g) and yield per vine (7.7 kg and 8.8 kg) in both summer and winter season crops respectively. Hence, the present study emphasizes that fruit bagging improves the yield attributes in grapes.

Papaya (Carica papaya L.) is a highly nutritious fruit crop cultivated commercially in the tropical and subtropical regions of the world. Being a shallow rooted fruit crop, it requires frequent application of nutrients. Papaya is highly remunerative due to its high productivity and responds positively to nutrient application. Papaya Ring Spot Virus (PRSV) is a major threat to papaya production, which causes severe yield loss and reduces fruit quality. To combat PRSV and enhance productivity, a nutrient formulation was developed by combining organic, inorganic nutrient sources with biocontrol agents to improve the health and vigor of the plants. Experiments were conducted to standardize the application time and evaluate the efficacy of nutrient formulation in enhancing yield, and to combat papaya ring spot virus (PRSV) incidence in papaya from January 2021 to December 2023 at Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India. The results revealed that foliar application of nutrient formulation at monthly intervals from the 3rd to the 7th month after planting (MAP) along with regular application of recommended dose of fertilizers (RDF) at bimonthly intervals from the 3rd MAP significantly increased the yield (37.79% and 30.57% in TNAU Papaya CO 8 and Red Lady, respectively) and reduced PRSV disease incidence (22.49% in TNAU Papaya CO 8 and 16.53% in Red Lady). Metabolomics study indicates that foliar spray of nutrient formulation enhanced the activators and precursors of defense enzymes, viz., peroxidase (PO), polyphenol oxidase (PPO), phenyl ammonia lyase (PAL), catalase (CAT) and nitrate reductase (NRase) in the sprayed plants over unsprayed control. Therefore, the sprayed plants exhibited tolerance to PRSV incidence by maintaining vigor and induced systemic resistance by the defense enzymes.