EFFECT OF PRE-HARVEST TREATMENTS OF CALCIUM SALTS ON HARVEST MA TURITY IN KINNOW MANDARIN Tanjeet Singh Chahal and J. S. Bal 1 F.R.S. Gangian (PAU), Hoshiyarpur 1 Department of Agriculture, Khalsa College, Amritsar, Punjab E-mail: tanjeetchahal@yahoo.com ABSTRACT : The present study was undertaken at Punjab Government Progeny Orchard and Nursery, Attari, Amritsar, to judge the efficacy of different levels of Calcium Chloride (CaCl 2 ) and Calcium Nitrate {Ca(NO 3 ) 2 } for retaining the fruit quality during delayed harvesting. There were six chemical treatments and the experiment was replicated three times. The fruits from the trees were harvested at different stages of maturity (1 st January, 15 th January, 1 st February and 15 th February) and were subjected to physico-chemical evaluation. On the basis of two years observation, Calcium Chloride (CaCl 2 ) at 6 per cent and Calcium Nitrate {Ca(NO 3 ) 2 }at 0.3 per cent proved their effectiveness in delaying the harvest maturity of the fruits. However, the TSS, total sugars and reducing sugars level of these treated fruits was find to be lower in comparison to control. The acidity level was recorded to be higher than control. Keywords : Calcium chloride, calcium nitrate, apparent maturity. In India Citrus is grown in an extremely varied conditions, right from arid and semi-arid areas of Rajasthen, Punjab and Haryana to humid tropical areas of north-east India, considered to be the possible place from where citrus has travelled to countries which are today claimed to have revolutionarised the art of citrus production. This has given citrus a status of most promising fruit crop which has a great scope of world trade (Singh and Srivastava, 14). Mandarins are the most prominent among citrus fruits in India. The mandarin cultivar Kinnow occupies a predominant position in Punjab and has become a highly successful commercial fruit crop. A large plantation has been brought under Kinnow fruit crop during the last two decades in Punjab, consequently, increased production is posing serious handling problems and invites research on expanding the harvesting maturity. As the harvesting of Kinnow is confined to a limited period, market glut is the serious problem faced by the growers, which engage the attention of horticulturists to delay its harvesting period. This process can help to overcome the hurdles in further expansion and regulation of marketing. In our country, cool chain system has not developed yet which necessitates to find out alternative measures for regulated market. The efficiency of calcium salts in checking the time of harvesting in citrus has been advocated by very few investigators. Calcium salts are known to be involved in number of physiological processes concerning membrane structure, functioning and enzyme activity. The investigations were conducted with the aim to find out the possibility of expanding the harvesting period with the help of CaCl 2 and Ca(NO 3 ) 2 along with their threshold levels. MA TERIALS AND METHODS The uniform and disease free trees of Kinnow of 15 years age were selected for the investigations from ‘Punjab Government Progeny Orchard’ Attari, Amritsar. All the plants were applied with standard doses of fertilizers and plant protection measures as recommended by Punjab Agricultural University, Ludhiana. The pre-harvest treatments of Calcium Chloride (CaCl 2 ) 4, 6 per cent, Calcium Nitrate {Ca(NO 3 ) 2 } 0.1, 0.2 0.3 per cent and control (Spray of water) were applied on 25 th October during both the experimental years. During the experiment 6 treatments were carried out. Two trees were kept as unit treatment HortFlora Research Spectrum, 1(2): 153-157 (2012) ISSN : 2250-2823 Received : 15.1.2012 Accepted : 8.2.2012