S16 - Session P3 - Effect of trunk girdling on fruit production, quality and storability in A. chinensis var. chinensis 'Zesy002'; in Italy

Authors: Francesco Spinelli *, Irene Donati , Claudia Onofrietti , Niccolò Raule, Antonio Cellini, Letizia Manzoni, Evangelos Xylogiannis

The effects of different trunk girdling practices on yield, fruit quality, postharvest and shelf-life performances A. chinensis var. chinensis 'Zesy002' (Zespri® Sungold) fruit was investigated in Italian conditions. The possible effects of girdling on the long-term accumulation of carbohydrates in different plant organs were also evaluated, to verify whether the temporary interruption of phloem flow may cause chronic starvation of the root system and affect budbreak and canopy growth in the following seasons. For this reason, the study was conducted for 3 growing seasons from 2018 till 2020 in two different orchards located in Cori (Latina Province, Italy). During preharvest, fruit produced from girdled plants showed an increase in the average size and dry matter compared to the control, with a positive trend over the entire vegetative season, being the best results generally obtained with the 4 incisions treatment (20+40+85+105 days after full bloom (DAFB)). The wound healing time ranged from 25 to 45 days and it was influenced by the environmental conditions and the number of incisions. Furthermore, in the second year of experiment, wounds required a considerably longer time to heal than those of the previous year. The effect of girdling strategy on postharvest performances varied according to the orchard and the harvest time (early, main or late pack). Late-harvest fruit had a generally higher firmness and soluble sugar content values than fruit harvested at mainpack. Trunk girdling increased the economic return, to a different extent based on the orchard management and the harvesting date from 7% (20+105 DAFB) to 44% (20+40+85 DAFB at late harvest). In this study, girdling application did not negatively affect the root sugar content in the long term, therefore, according to the results obtained, girdling could represent a sustainable practice to have high-quality kiwifruits, with high dry matter content and increased fruit size and weight.