Resistance in some Malus spp. to root canker caused by Peniophora sacrata

Abstract

A method was developed for measuring differences in the resistance of apple rootstocks to the indigenous fungus Peniophora sacrata. Only low-moderate levels of resistance were present in rootstocks of common apple, Malus sylvestris, but a normal distribution in such resistance suggested that higher levels of resistance might be found in Malus spp. from which the common apple had been derived. Such levels of resistance were found in some seedlings of the species M. baccata, M. prunifolia, and their hybrid M. x robusta. The most resistant seedlings have been selected, named in the “Aotea Series”, and will be tested under field conditions, both for resistance and horticultural merit.