Effect of pre-harvest application of potassium nitrate, naphthalene acetic acid and ethephon on ripening and shelf-life of guava cv. Allahabad Safeda

The current study, effect of pre-harvest application of potassium nitrate (KNO3), naphthalene acetic acid (NAA) and ethephon on ripening and shelf-life of guava (Psidium guajava L.) cv. Allahabad Safeda was undertaken at the Fruit Research Farm, Dr B R S Agri at Sri Muktsar Sahib, Punjab. The experiment was carried out on an eight-year-old guava tree of the Allahabad Safeda. The trees were sprayed with various doses of chemicals, KNO3 (1.0, 1.5, 2.0%), NAA (200, 300, 400 ppm) and ethephon (200, 400, 600 ppm) during the third week of November. The fruits were harvested at the hard ripe stage on 19 December, placed in Corrugated fibre box (CFB) of 4 kg capacity and stored at ambient temperature. In ambient storage, guava fruits were remain acceptable for up to 6 days of storage without any adverse effect on fruit quality. KNO3 (1.5 and 2.0%), NAA (300 ppm) and ethephon (200 ppm) recorded a reduction in physiological loss of weight and spoilage and KNO3 (2.0%) maintaining fruit firmness (7.64 kg/cm2), palatability rating (8.00) throughout the storage period. However, the highest storage life and good-quality fruits was recorded with the application of KNO3 (1.5, 2%) during ambient storage. At lower concentrations, ethephon also helps to enhance the ripening of fruits, contrast to this fruits treated with NAA delayed the fruit senescense.