EFFECT OF POST HARVEST CALCIUM TREATMENTS ON SHELF LIFE OF GUAVA CV. SARDAR Rajesh Kumar, Shant Lal and K.K. Misra Department of Horticulture, College of Agriculture, G. B. Pant University of Agriculture and Technology, Pantnagar-263 145, U.S. Nagar (Uttarakhand) Email: kamboj783@yahoo.com ABSTRACT: The search for techniques that extend shelf life of guava (Psidium guajava) fruits, and reduce its postharvest losses is desirable. The objective of this work was to evaluate the effects of concentrations of competitive ethylene antagonist calcium salts on conservation of ‘Sardar’ guava fruits. Treatments consisted of 0.5%, 1% Calcium Nitrate, 1%, 2% Calcium Chloride and 0.5%, 1% Calcium Sulphate for 12 days followed by storage at room temperature. The application of 1% calcium chloride for 12 days was efficient in delaying loss of skin color and in keeping fruit firm at room temperature storage. The calcium nitrate at 1% concentration was efficient in delaying skin colour loss only when fruits were stored at 25°C. The effect of calcium nitrate was quite significant on the reduction of acceptability in both the year. The product was efficient in delaying the ripening of fruits and the calcium chloride 1% showed the best effect. Keywords: Psidium guajava, calcium salts, postharvest, shelf life. Guava is a highly perishable fruit that shows intense metabolic activity. Guava fruit becomes fully ripe between three and five days at room temperature. Due to such perishability, the control of fruit ripening is fundamental for increasing shelf life after harvest. The main factors depreciating postharvest quality in guava are fast loss of green color, excessive softening, high rot incidence and loss of turgidity. Storage under low temperatures has been considered the most efficient method to maintain quality of most fruits due to its effects on reducing respiration rate, transpiration, ethylene production, ripening, senescence and rot development. In climacteric fruits, like most guava varieties, the reduction of temperature delays the climacteric peak and, consequently, ripening. The recent finding that calcium salts interferes with ethylene link to its binding site represents a new and powerful tool for postharvest management of climacteric fruits. It has been demonstrated that the inhibition of the ethylene action delays ripening and senescence in several species of fruits, such as custard apple, guava, papaya, peach, apple, avocado, banana, strawberry and tomato. Previous finding revealed that post-harvest treat of various calcium compounds and packaging material have enhanced their shelf life, reducedment the spoilage and improved the fruit quality by delaying the onset of senescence during storage. Keeping in view the importance on crop, a study was carried out to study the effect of these compounds on storage life of guava cv. Sardar. MA TERIALS AND METHODS Healthy, firm, mature and uniform sized fruits of guava cv. Sardar were procured from a Horticulture Research Centre, Pattharchata on December 2007 and December 2008. The analysis carried out at post harvest laboratory of the Department of Horticulture, College of Agriculture, G.B. Pant University of Agriculture and Technology, Pantnagar. The selected fruits were cleaned, dried and treated dip method with Ca(NO 3 ) 2 (0.5% & 1%), CaCl 2 (1% & 2%) and CaSO 4 (0.5% & 1%) and subsequently packed in newspaper and stored at room temperature (28-33°C) and 85-90% relative humidity. There were seven treatments replicated thrice in a completely randomized design (CRD). Fruit samples, each comprising of 5 fruits, were drawn from each treatment at the time of storage and subsequently after 0, 3, 6, 9 and 12 days of storage for physico-chemicals analysis. The fruits were evaluated for palatability rating by a panel of 7 judges on a score card (10 points). Reducing sugar, HortFlora Research Spectrum, 1(4): 344-347 (2012) ISSN : 2250-2823 Received : 24.7.2012 Accepted : 18.8.2012