Vegetative and reproductive growth of ‘Fuji’ and ‘Rosy Glow’ trees grafted on ‘Geneva’ rootstocks as an alternative to ‘M9’

In the Po Valley, the apple ‘M9’ rootstock has always been the one mostly adopted although recently it is undergoing a slow decrease in its utilization. The main causes of this phenomenon are soil fatigue, new pests and diseases, new cultivation systems, and poor adaptability to new environmental conditions due to climate change. An experimental orchard for the comparison of rootstocks produced by the Geneva research program, was set up in 2020 at the F.lli Navarra Agriculture Foundation in Malborghetto di Boara (FE). The purpose of the trial was to evaluate the performance of four different Geneva rootstocks in the Po Valley: ‘CG969’, ‘CG11’, ‘CG210’, ‘CG935’ in comparison with the control ‘M9 T337’. The trial was set up with a randomized block scheme including two varieties suitable for lowland production, ‘Fuji’ and ‘Rosy Glow’. The parameters measured were related to the vegetative- productive growth, canopy light penetration, fruit quality at harvest, and return bloom. In the cv ‘Fuji’, ‘CG935’ rootstock showed the best performance in comparison with ‘M9 T337’ control, while for the cv ‘Rosy Glow’, ‘CG210’ rootstock showed the best responses. However, since rootstock effects may differ from site to site, further studies are needed, over several productive seasons to evaluate them in relation to the environmental conditions and the peculiarity of the growing area.