Baltic fruit rootstock studies: evaluation of 12 rootstocks for apple cultivar 'Auksis'

In the frame of Baltic fruit rootstock studies program apple trees of cultivar ‘Auksis’ (Malus domestica Borkh.) grown on 12 dwarf rootstocks were planted in Estonia, Latvia, Lithuania and Byelorussia in 2001 and evaluated for five years. Dwarf rootstocks included four selections from the Budagovski series (B.9, B.146, B.396, B.491), three from the Polish series (P 2, P 22, P 60), M.9, M.26, York 9, Bulboga (Moldavian selection) and Pure 1 (Latvian selection). The strongest tree growth was recorded in Lithuania and Byelorussia. The highest yields were obtained in Lithuania. All tested rootstocks according growth vigour control can be grouped in the following way: less vigour than M.9 – P 22, the same as M.9 – Pure 1, B.396, York 9, P.60, B.9 and P 2, between M.9 and M.26 – B.491, the same or more vigorous as M.26 – Bulboga and B.146. Trees on rootstocks Pure 1 gave the highest cumulative yield and were the most efficient although there was no significant difference in cumulative fertility index with trees growing on rootstocks P 22, P 2, M.9, B.9 and York 9. The least efficient were trees on rootstocks Bulboga and B.146. Rootstock and location interaction was recorded for B.491 and P.60 in growth vigour control, York 9 in total yield, and B.9 in yield efficiency.