Pre-Harvest Calcium Treatments Modulate Ambient Storage Behaviour and Postharvest Quality of Guava (Psidium guajava L.) cv. Hisar Safeda during Rainy and Winter Seasons

Abstract

Guava is highly perishable under ambient conditions, and pre-harvest calcium management may modify postharvest deterioration through effects on tissue integrity and ripening. This study evaluated three calcium sources—calcium chloride, calcium nitrate and calcium sulphate—each at 0.5%, 1.0% and 1.5%, against a water-sprayed control in guava cv. Hisar Safeda during rainy- and winter-season crops at Hisar, India. Pre-harvest sprays were applied in the last week of June and November during 2022–23. Fully mature fruits were stored under ambient conditions and assessed on alternate days to day 6 in the rainy season and day 8 in winter. Calcium source and concentration significantly influenced moisture content, specific gravity, physiological loss in weight, decay, firmness and sensory quality. Calcium nitrate at 1.5% gave the lowest mean physiological loss in weight (8.51% rainy; 6.91% winter) and the lowest mean decay (27.08% rainy; 27.22% winter), while also obtaining the highest mean sensory ratings (7.33 and 7.60, respectively). Calcium chloride at 1.5% provided the greatest mean firmness (4.01 and 5.79 kg cm−2) and the highest mean moisture content (79.11% and 78.33%). Deterioration was numerically slower in winter fruit: at day 6, mean physiological loss in weight was 12.55% in winter compared with 19.52% in the rainy crop, and mean sensory rating was 6.07 compared with 4.43. Because the thesis analysis did not report season as a common factorial term, these seasonal contrasts are descriptive. The results indicate complementary benefits of calcium nitrate for limiting weight loss and decay and calcium chloride for retaining firmness, with 1.5% concentrations consistently among the strongest treatments.