Pear Flowering, Fruit Set, and Pre-Harvest Fruit Drop Rate: The Role of Rootstocks

Abstract

This research was performed to clarify to what extent the rootstocks (Quince BA29, Quince A [QA], FOX9, FOX11, OHxF333, OHxF87, FAROLD40, and European pear seedling rootstocks) could be impactful on flower formation, fruit set and pre-harvest fruit drop ratio while combined with 'Santa Maria', 'Williams', and 'Deveci' pear cultivars during 3 consecutive research years of 2021-2023. The rootstocks, cultivars, and research years had a significant effect on examining all characteristics. The highest number of opened flowers (NOF) (1389.6 pieces tree-1) and number of flowers turned to fruit (NFTF) (507.9 pieces tree-1) were detected in the QA rootstocks and the lowest in the FOX9 (NOF 100.8 pieces tree-1, NFTF 22.8 pieces tree-1) followed by OHxF87 rootstocks (NOF 94.5 pieces tree-1, NFTF 33.4 pieces tree-1). The highest fruit set ratio (FSR) was observed in the FOX11 (52.7%), followed by BA29 rootstock (52.6%), and the lowest FSR was recorded in the seedling rootstock (10.6%). The main effect of cultivars and rootstocks on the pre-harvest fruit drop rate (PHFDR) was significant. While the PHFDR was lower in FOX9 and OHxF87 rootstocks than in other rootstocks, 'Williams' was observed to have the highest and 'Deveci' to have the lowest PHFDR in terms of cultivars. In conclusion, out of the three different cultivars that were used in the study, the 'Deveci' cultivar produced a high number of flowers, while 'Santa Maria' produced the highest fruits and FSR compared to the 'Williams cultivar. It could be suggested that the 'Santa Maria' cultivar grafted onto BA29 and FOX11 rootstocks is especially suitable for the region where the fruit set is high.