STORING OF PEARS cv. YANIS WITH POSTHARVEST ETHYLENE INHIBITOR TREATMENT, DEPENDING ON HARVEST DATE AND POST-HARVEST

The article coveres the research results of natural losses and changes in marketable quality of pears cv. Yanis (Noyabrska) for mass and late harvesting during refrigeration storage, depending on the cooling delay after harvest and postharvest treatment with 1-methylcyclopropene (1-MCP). Pears were harvested in two terms – the first, with the onset of harvest maturity (beginning of harvest maturity, mass collection) and the second one a week later (full harvesting maturity, late collection), taking into account flesh firmness, content of dry soluble substances and iodine-starch test. Homogeneous in degree of ripeness, products of a higher commodity grade with a diameter of not less than 70 mm were selected from typical trees, which were placed in boxes of 15 kg capacity with chess laying and overlaying of each layer with paper. Also, polyethylene nets with fruits were placed there to record for natural losses. The number of boxes of each variant corresponded to the periodicity of the commodity analysis. After harvesting, part of the fruit was immediately cooled at 5±1 °C and 85–90 % relative humidity, the other part was cooled after a 24-hour exposure at a temperature of 18...20 °C and relative humidity of 55...60 %. The next day, the fruits were treated with 1-MCP with an experimental dose of 500 ppb (0.034 g/m3) of Smart Fresh. After 24 hour-exposure, the container was removed, the treated and control fruits were stored in a refrigerated chamber at a temperature of 2±0.5 °C and relative humidity of 85–90 %. It has been found out that for a rational fertilization system of a pear orchard and post-harvest treatment with a dose of 500 ppb 1-MCP at a temperature of 2±0.5 °С, a successful, with a 90 % output of marketable products, six-month refrigerated storage of pears from a mass collection (regardless of 24-hour cooling delay) was achieved. Similar results were also obtained for fruits collected in late harvest maturity, regardless of the delayed cooling and treatment of 1-MCP. During six-month storage, there were no losses due to browning of the skin and the pulp and 3.2 times less losses from the rotting of fruits of mass collection with a delay of cooling and post-harvest treatment of 1-MCP. Under the excessive use of potassium fertilizers, only four-month storage of fruits with 90 % output of marketable products is possible, with the exception of untreated 1-MCP and instantly cooled fruit of mass collection. After treatment with an ethylene inhibitor, after a six-month storage, the output of marketable products for fruit of mass collection was 3.1–6.1 times higher and the output for late-harvested fruits with less losses from flesh browning was 1.2–2.4 times higher. Regardless of the cooling delay, post-harvest 1-MCP ensures the lack of rotting in pears of mass harvesting with insignificant effects on the level of natural product losses