GROWTH AND YIELD OF GOLDEN DELICIOUS ON M. 9A AND ON THREE OTHER M.9 ROOTSTOCK SOURCES
Four sources of M.9 were compared in an orchard trial with the variety Golden Delicious. The source M.9a is difficult to propagate in the stoolbed, and the question of whether this property also affects growth and yield of varieties budded on this rootstock is being investigated. The four M.9 sources differ in virus content. Yield efficiency was determined for each object after five years of production. On the basis of the kg/cm and kg/cm2 ratios, trees on virus-free M.9 were the best, followed by those on M.9a. But on the basis of kg/m3 and kg/kg of pruning wood, the values for M.9a were higher than for trees on virus-free and virus-infected M.9 sources. The results indicate that differences between M.9 sources may occur in the nursery and the orchard as well.
van Oosten, H.J. (1977). GROWTH AND YIELD OF GOLDEN DELICIOUS ON M. 9A AND ON THREE OTHER M.9 ROOTSTOCK SOURCES. Acta Hortic. 75, 157-162