Apple rootstock studies:: Comparison of Polish, Russian, USA and UK selections as rootstocks for the apple cultivar Cox's Orange Pippin (Malus domestica Borkh.)

Eleven apple rootstocks, originating in Poland, Russia, the USA and the UK, were evaluated for the scion cv. Cox's Orange Pippin ('Cox'), grown without supplementary irrigation in south-east England. Two of the rootstocks, B.146 and P.22, produced trees that were more dwarfed, suckered more and bore fruit smaller than those on trees on M.27-EMLA. Trees on P.2 were intermediate in vigour between those on M.27-EMLA and those on M.9-EMLA and these trees exhibited good yield precocity and yield efficiency. 'Cox' trees on P.16, MAC.9, B.9 and M.9-EMLA were similar in vigour. Although trees on P.16, MAC.9 and B.9 rootstocks induced good yield precocity and efficiency (yield per unit tree crown volume) and produced fruits of good size and quality, none of these rootstocks was considered superior to M.9-EMLA, Trees on MM.111, which were of intermediate vigour, performed slightly better in terms of yield efficiency than trees on MM.106 and much better than trees on P.18.