Effects of shoot age on biological and chemical properties of red currant (Ribes rubrum L.) cultivars

The aim of this study was to examine the influence of shoot age on biological and chemical properties of 11 red currant cultivars (‘Jonkheer van Tets’, ‘Junifer’, ‘London Market’, ‘Makosta’, ‘Mirana’, ‘Redpoll’, ‘Rolan’, ‘Rondom’, ‘Rovada’, ‘Slovakia’ and ‘Stanza’) with different origins and ripening times. Phenological observations and pomological characteristics were studied and chemical analysis was conducted from 2013 to 2018 at experimental fields near Belgrade, Serbia. The total contents of phenols and anthocyanin were estimated spectrophotometrically, while quantitative analysis of anthocyanin aglycones was done using high-performance liquid chromatography. Three-year-old shoots had an earlier start of all examined phenological stages, better generative potential, higher yields, as well as higher total phenol and vitamin C contents in the fruits, compared with 2-year-old shoots, for all cultivars. The contents of total anthocyanins were higher in berries on younger shoots of early-ripening cultivars, while late-ripening cultivars had higher contents of total soluble solids and cyanidin in the berries on 3-year-old shoots. Principal component analysis demonstrated that the most important variables that distinguished 2-year-old shoots from 3-year-old shoots were those related to phenological data, cluster traits, total acids and yields. According to the obtained results, ‘Junifer’ (with the highest number of clusters), ‘Mirana’ (with the highest sugar content and sugar/acid ratio), ‘Redpoll’ (with the highest physical traits of cluster and berry), ‘Slovakia’ (with the highest yield and yield efficiency) and ‘Rovada’ (with the highest level of secondary metabolites) are recommended as the most promising cultivars for growing in the temperate region of Serbia.