Effect of Pre-Harvest Application of Gibberellic Acid on Fruit Quality and Shelf Life of Mandarin (Citrus reticulata Blanco)

Mandarin (Citrus reticulata Blanco) is a promising fruit crop gaining popularity for its human nutrition and economic importance in Nepal. The qualitative losses during pre-harvest stage hinder the productivity and subsequently shorten the on-tree storability. An experiment was conducted to assess the effect of gibberellic acid on quality and shelf life of the mandarin fruit. GA3 at 10, 20, and 30 ppm as against of control were evaluated. Observations on fruit weight (g), fruit firmness (kg/cm2), rind colour (1 - 5 index), juice recovery (%), TSS/acid ratio, PLW (%), decay loss (%), and ascorbic acid (mg/100 ml) were recorded at three harvesting dates i.e. 20 Nov, 5 Dec, and 20 Dec and storage condition. It has been revealed that the fruits treated with GA3 at 20 ppm retained higher fruit weight (128.6 g), more firmness (3.54 kg/cm2), better juice recovery (57.75%), and greater TSS/acid ratio (21.24) at the end of study (20 December). The PLW was found less with GA3 at 30 ppm in both ambient (5.17%) and cellar (6.69%) condition as against untreated fruits (9.52% and 11.76%). Similarly, the decay loss was minimum in the fruits treated with GA3 at 30 ppm both with ambient (1.02%) and cellar condition (8.21%) as against control with ambient (5.54%) and cellar (21.58%).

Effect of Altitude and Maturity Stages on Quality Attributes of Mandarin (Citrus reticulata Blanco)

Mandarin (Citrus reticulata Blanco) is a premier fruit crop which ranks in first position of the total fruit industry in Nepal. Studies were conducted to assess the maturity indices and quality parameters of mandarin at three altitudes i.e. 1300 m·asl, 1000 m·asl, and 700 m·asl with six maturity stages i.e. 11 Oct, 21 Oct, 31 Oct, 10 Nov, 20 Nov, and 30 Nov. The most important and reliable judging criteria of fruit maturity in mandarin i.e. fruit weight, external fruit colour, firmness, TSS, acidity, and TSS/Acid ratio, and vitamin C were experimented. The experiment results revealed that 1000 m·asl location was showed the highest fruit weight (104.9 g) and juice percentage (55.23) followed by 1300 m·asl altitude (99.5 g and 53.75% respectively) at 20th of November. The maturity advanced at lower altitude with 50 percent yellow orange rind colour, 10.98 TSS/acid ratio and 4 kg/cm2 firmness from 10th November at lower altitudes whereas it was appeared in 20th November at higher altitudes. The TSS/acid ratio was significantly higher (10.98) in the fruits of 700 m·asl as compared to 1300 m·asl (9.76) on 10th November, however, on 20th November 1300 m·asl showed the highest ratio (17.76). The fruit weight, juice content, TSS was found in increasing trends up to 20 November and then showed constant and decreasing trend. However, TA, firmness and vitamin C were showed in decreasing trends with time. The 1000 - 1300 m·asl was the best location for the mandarin production and 10-20 November was the best period for the mandarin harvesting for optimum maturity.

Effect of Postharvest Treatments on Quality and Shelf Life of Mandarin (Citrus reticulata Blanco)

Nepal produces large quantity of mandarin (Citrus reticulata Blanco) annually but faces big losses due to improper postharvest treatments. The experiment was carried out during 2012-2013 with the objective of assessing the effect of different postharvest treatments on quality and shelf life of mandarin. The postharvest treatments were: wax emulsion at 10%, bavistin at 0.1%, wax at 10% with bavistin at 0.1%, calcium chloride at 1%, Jeevatu at 5% along with untreated fruits as a control. The experiment was conducted for four weeks of storage at ambient condition in Nepal Agricultural Research Council, Khumaltar, Kathmandu. Wax in combination with bavistin was found as the most effective in reducing the physiological loss in weight, whereas bavistin proved to reduce decay loss up to four weeks of storage. The fruits treated with wax alone and with combination of bavistin retained maximum firmness, juice percentage, vitamin C and palatability rating during the storage. The minimum total soluble solid and maximum titrable acidity were recorded in the fruits treated with wax plus bavistin. The present findings indicate that mandarin can be stored up to four weeks when treated with wax as well as wax with bavistin in the condition with 14°C - 18°C temperature and 45% - 73% relative humidity.