Best practices to avoid fruit drop in an early cultivation of redcurrant

Early spring production of redcurrant (Ribes rubrum) cultivar ‘Junifer’ in heated greenhouses can be an economically sound move. However, several pitfalls can make this intensive and costly cultivation fail. Besides production, truss quality determines the financial result. Only sufficiently long racemes with uninterrupted fruit are sold at a high price. Fruit drop at the flowering or fruit set stages is the biggest failure factor for this crop. A combination of various climatic, physiological, or technical factors can cause fruit drop. After more than 25 years of research, the problem has not been completely understood. However, numerous parameters were examined separately and mixed, and best practices could be drawn up. Based on this research, it is known that temperature, humidity, and lighting are essential climatic parameters influencing fruit drop. Cultivation techniques such as winter and summer pruning, bunch thinning, plant density, and fungus suppression can reduce fruit drop. Physiological traits such as pollination, growth regulation, and the number of cold hours are also important parameters. A best practice guide for growers should ensure that this crop can be carried out with minimum risk and maximum return.