Performance of the NC-140 Cooperative Apple Rootstock Planting: I. Survival, Tree Size, Yield and Fruit Size

Abstract

In 1984, trees of ‘Starkspur Supreme Delicious’ apple ( Malus x domesticaBorkh) on 15 rootstocks were planted at 31 sites in North America according to guidelines established for cooperative testing by the North Central Regional Cooperative Project (NC-140). Tree loss was greatest on P.22 (32%) and MAC.39 (21%). Trees on P.18, A.313, B.490, MAC.1 and M.4 had trunk cross-sectional areas (TCA) and yield efficiencies similar to seedling (SDL). P.1 produced trees similar in size, production and yield efficiency to M.7EMLA. C6 and M.26EMLA resulted in trees of similar size, yield and yield efficiency MAC.39 and B.9 had similar TCA's, yield ana yield efficiency, but trees on B.9 were shorter with smaller spread. Fruit size over 6 years from trees on P.22, M.4 and SDL was small, while fruit size tended to be large from trees on P.18, A.313 and C6.