Effect of Botanical and Chemical Treatments on Post-Harvest Quality and Shelf Life of Mandarin (Citrus reticulata Blanco)

Mandarin (Citrus reticulata Blanco) is an important commercial fruit crop in Nepal, but its high perishability and inadequate postharvest management contribute to considerable quality deterioration and storage losses. This study evaluated the effectiveness of selected botanical and chemical treatments in maintaining postharvest quality and extending the shelf life of mandarin fruits under ambient storage conditions. The experiment was conducted in a completely randomised design with seven treatments and four replications at the Horticulture Laboratory of the Citrus Development Centre, Tansen, Palpa, from January to April 2026. The treatments consisted of 15% Aloe vera extract, 15% ginger extract, 15% garlic extract, 4% calcium chloride, 4 mM salicylic acid, 30 ppm gibberellic acid, and distilled water as the control. The experiment was conducted from January to April 2026 under ambient storage conditions (23–27°C and 65–75% relative humidity). Physicochemical quality parameters were assessed at seven-day intervals until 42 days after treatment (DAT), while shelf-life monitoring continued separately until 50% of the fruits exhibited visible decay or became unmarketable. The treatments significantly influenced several quality attributes during the later stages of storage. Aloe vera extract was the most effective in reducing physiological weight loss and retaining juice content, whereas calcium chloride showed greater retention of titratable acidity. Aloe vera-treated fruits also maintained a comparatively lower TSS/TA ratio, indicating better retention of the sugar–acid balance. Shelf life differed significantly among treatments, with Aloe vera providing the longest storage life (70.75 days), followed by calcium chloride (64.25 days), compared with 47.25 days for the control. Overall, Aloe vera extract 15% showed the most consistent performance, followed by calcium chloride 4%, in maintaining postharvest quality and extending the marketable shelf life of mandarin fruits under ambient conditions. These treatments may therefore provide practical options for reducing postharvest deterioration and losses in mandarin.