Does the rootstock affect alternate bearing of apple tree?

Rootstock effect on apple alternate bearing was investigated in different rootstock trials performed at the Institute of Horticulture Lithuanian Research Centre for Agriculture and Forestry during 1995-2014. Impact of rootstock was evaluated with apple cultivars of different bearing behaviour including 'Ligol', 'Auksis' and 'Beloruskoje malinovoje'. These studies included semi-dwarf rootstocks M.26, Bulboga, B.146; dwarf rootstocks M.9, B.9, B.491, B.396, P 2, P 60, P 66, P 67, Jork 9, and Pure 1; super-dwarf rootstocks P 59, P 22, P 61, P 62, and PB.4. Apple tree alternate bearing in different trials was investigated 6 years in full bearing orchards. Apple alternate bearing did not depend on rootstock vigour class. Correlations between bearing regularity, total cumulative yield and crop load were not observed. Cultivar had a higher impact on apple bearing than rootstock. Some rootstock-cultivar interactions occurred pointing at the necessity to investigate optimal rootstock-cultivar combinations.