Physical and mechanical properties of berries and biological features of red currant growth for mechanized harvesting

The physical and mechanical parameters of berries and the morphometric features of the structure of the bush growth habit are important criteria in predicting the use of berry harvesting equipment. In this research, six red currant cultivars have been studied. The berry separation force, the crushing force, and the strength of attachment of the berries to the stalk were assigned to the physical and mechanical parameters and were determined using the "PLODTEST-1" and "Dina-2" devices (Russia). For the optimal operation of the berry harvester, the crushing force of the berries must be more than 2 N, the berry separation force must be in the range of 0.5–1.5 N. A high correlation between the separation and crushing forces was determined (R = 0.71). During the period of technical maturity, the strength of the attachment of the berries in the raceme was more than 0.5 N and, by the end of maturation, this indicator decreased. Most of the studied cultivars have a compact, optimal bush volume. The red currant cultivars Niva, Asya and Vika are promising for mechanised harvesting.