Association of hydrothermal conditions one month before harvest and degree of maturity with the yield of sound apple fruit aft er storage

Abstract

The quality and storability of apple fruits depend on the apple variety and degree of maturity, as well as weather conditions of the growing season. For each pomological variety, the picking maturity of the fruit is individual. It depends on geographical and climatic area of cultivation, weather conditions of a particular season – the hydrothermal conditions of the active growing season (the sum of active temperatures, precipitation and hydrothermal coefficient (HTC)). Fruits should be harvested at the optimal maturity stage to ensure maximum duration of storage and preservation of fruit quality. The paper presents a quantitative assessment of the impact of weather conditions one month before harvesting in different years (2014, 2016, 2018, 2019) on the yield of sound apple fruits of Priokskoye and Rozhdestvenskoe breeding varieties (the Russian Research Institute of Fruit Crop Breeding) after storage at +2 °С. A certain regularity was revealed in the yield of marketable fruits after storage, depending on hydrothermal conditions, 30 days before harvesting. Regression equations for Priokskoye and Rozhdestvenskoye varieties grown in central Russia were obtained on the basis of HTC indicators and the joint effect of the sum of active temperatures ≥ 10°C and HTC. The equations can be used to predict the yield of sound fruits after storage, by interpolating and extrapolating empirically obtained data.