Yield and Fruit Quality Responses of Guava (Psidium guajava L.) cv. Hisar Safeda to Pre-Harvest Calcium Sources and Concentrations during Rainy and Winter Seasons

Abstract

Pre-harvest mineral management can influence both productivity and the quality with which highly perishable guava fruit enters the postharvest chain. This study evaluated three calcium salts—calcium chloride, calcium nitrate and calcium sulphate—each at 0.5, 1.0 and 1.5%, together with a water-sprayed control, in guava (Psidium guajava L.) cv. Hisar Safeda during rainy- and winter-season crops at Hisar, Haryana, India, in 2022–23. The field experiment comprised three replications. Harvest responses included fruit number, fruit weight, yield, total soluble solids (TSS), titratable acidity, TSS:acid ratio, reducing, non-reducing and total sugars, ascorbic acid, pectin and total phenolics. Calcium nitrate at 1.5% produced the highest fruit number, mean fruit weight, yield per tree and yield per hectare in both seasons; corresponding yields were 107.6 kg tree−1 and 27.56 t ha−1 in the rainy crop and 91.81 kg tree−1 and 23.50 t ha−1 in the winter crop. The same treatment also produced the highest TSS, TSS:acid ratio and sugar fractions and the lowest titratable acidity. In contrast, calcium chloride at 1.5% produced the highest ascorbic acid, pectin and phenolic contents in both seasons. Winter fruit generally showed higher soluble-solids, sugar, ascorbic-acid and pectin values than rainy-season fruit, whereas yield values were numerically higher in the rainy crop; these seasonal contrasts are descriptive because the thesis reported season-specific analyses. The findings indicate source-specific rather than universal superiority among calcium salts and support calcium nitrate and calcium chloride as distinct pre-harvest options for productivity/compositional and nutritional-structural quality objectives, respectively. Multi-location and multi-year validation with fruit mineral analysis is required before generalising treatment recommendations.