Evaluation of dwarf rootstocks for high-density and sustainable orchards in Latvia

It is challenging to find the most optimal cultivar rootstock combination for specific conditions in a particular region.
The most common rootstocks like ‘M9’ have insufficient winterhardiness and resistance to pests.
The apple breeding programs struggle to select new resistant cultivars, while the suitability for combination with rootstocks that could reduce the tree size and growth is unclear.
The study aimed to evaluate the graft compatibility of dwarf rootstock and selected cultivars adapted for Latvia’s orchard systems and conditions.
Performance of different origin cultivars ‘Gita’ (Vf), ‘Pamyat Semakinu’, ‘Alesya’ and ‘Alwa’ on rootstocks ‘Budagovsky 9’ (‘B.9’) and ‘PB4’ were tested for orchard system with 1923 tree density per ha.
During the past decade since the trial was started on both rootstocks, smaller growth was observed for cultivars ‘Pamyat’, Semakinu’, and ‘Alesya’. ‘Gita’ and ‘Alwa’ had higher productivity on both rootstocks.
The yield efficiency differs depending on cultivars; it was higher for ‘Gita’ and ‘Alesya’ on both rootstocks.
The cumulative yield per canopy was significantly larger for ‘Pamyat Semakinu’ on both rootstocks.
Cultivar ‘Pamyat Semakinu’ had larger fruit, while cultivars ‘Alesya’ and ‘Alwa’ had the smallest fruits.
A significant interaction of rootstocks and cultivars combination was observed in biennial bearing.
The biennial bearing was less pronounced in ‘Gita’, ‘Pamyat Semakinu’ and ‘Alesya’ on rootstock ‘PB.4’ than ‘B.9’. Cultivars ‘Gita’ on ‘B.9’ and ‘Alwa’ on ‘B.9’ and ‘PB.4’ performed oppositely.

XII International Symposium on Integrating Canopy, Rootstock and Environmental Physiology in Orchard Systems

E. Rubauskis, I. Borisova

Malus, yield efficiency, scab resistant, canopy volume, biennial bearing

https://doi.org/10.17660/ActaHortic.2022.1346.87