Influence of pre-harvest application of calcium and alar on post-harvest changes in cv. 'Sardar' guava fruits

Three consecutive sprays of calcium chloride (1 or 2%) or calcium nitrate (1 or 2%) were applied 18, 12, and 6 days before harvest and one spray of alar (500 or 1000 ppm) was applied 18 days before harvest on cv. 'Sardar' guava (Psidium guajava L.) trees. The fruits were stored under ambient conditions [12 +/- 3 degrees C and 74-87% relative humidity (RH)]. Calcium and alar treatments delayed ripening and had a favourable effect on the quality of the fruits during storage. In general, the treated fruits exhibited a higher calcium level in the fruit pulp, a lower cumulative physiological loss in weight, and had lower invertase and pectinase activities. Calcium nitrate was better than calcium chloride in prolonging the storability and quality of guava fruits. Alar (1000 ppm) or calcium nitrate (2%) was most efficient in maintaining the edible quality and marketability of guava fruits up to eight days of storage.