Articles
IMPROVED ROOTSTOCKS FOR APPLE TREES IN SUBTEMPERATE REGIONS
Evaluation of these rootstocks has been relative to these conditions and to the biotic hazards of this zone.
Behavior of these stocks under subtemperate conditions can be expected to be radically different.
Pathogens such as Armillaria, Clitocybe, Corticium, Rosellinia, Sclerotium and Xylaria seldom cause serious problems in older climates, but the diseases they incite under subtemperate and subtropical conditions can be catastrophic.
Similarly, the very acidic soils typical of southern Brazil pose toxicity problems not often encountered in the temperate zone.
Recently introduced apple rootstocks, selections from breeding programs, especially interspecific hybrids, and seedlings of a wide range of potential parents should be evaluated for adaptation to subtemperate conditions.