Virus Effects on the Performance of Apple Trees on Apomict Seedling Rootstocks

Abstract

SummaryTrees of a Worcester Pearmain apple seedling on Malus hupehensis and M. toringoides apomictic rootstocks were inoculated with six virus treatments, and growth and cropping were compared over an 8-year period. Some virus complexes caused a reduction in growth rate early in the experiment, and this continued throughout the period with the trees on both rootstocks. Several treatments reduced the cropping of the treesafter the third year; the number of flower clusters and the size, colour and maturity of the fruit were also affected.Trees of a Stoke Red cider apple seedling on Malus toringoides inoculated with six different virus treatments showed similar growth and cropping reductions over the same period.