Status of sweet cherry rootstocks collection at the RIH in Skierniewice, Poland, and performance of five clonal rootstocks in the orchard

Collection of vegetative rootstocks for stone fruit trees has been maintained at the Research Institute of Horticulture (RIH) in Skierniewice, since 1989. Presently, the collection includes 35 different genotypes. From among all rootstocks collected, 24 genotypes can be used for sweet cherry trees production. Most of them were investigated in different nursery and orchard experiments during the last 25 years. The article presents the results from the field experiment with 9-year-old 'Sylvia' and 'Karina' sweet cherry trees grafted on 'GiSelA 3', 'GiSelA 5', 'Piku 4, 'Weiroot 72' and 'F12/1' - as a standard, clonal rootstocks. Based on trunk cross-sectional area (TCSA), the largest 'Sylvia' and 'Karina' trees were grown on 'F12/1', and the smallest on 'GiSelA 3'. The results revealed that all of the tested rootstocks being compared to 'F 12/1', significantly reduced growth of sweet cherry trees. 'Sylvia' trees on 'GiSelA 5' and 'Piku 4' yielded more than those on 'F12/1'. The highest cumulative yields of 'Karina' were harvested from trees on 'GiSelA 5'. The cumulative yields of 'Karina' trees on 'GiSelA 3', 'Piku 4' and 'Weiroot 72' were comparable to those on 'F12/1'. Rootstock effects on yield efficiency were consistent between the two cultivars, with the most yield efficient trees on 'GiSelA 3', 'GiSelA 5' and 'Weiroot 72', and the least efficient trees on 'F12/1'. Trees of both cultivars grafted on 'GiSelA 3' produced significantly smaller fruit than those grafted on 'F 12/1'. The rest of the rootstocks, tested in terms of an effect on fruit weight (with the exception of 'Karina' on 'Weiroot 72'), had a similar value to 'F 12/1'.