Apple rootstocks: history, physiology, management and breeding

Authors: MARINI, RICHARD - Pennsylvania State University; Fazio, Gennaro

Submitted to: Horticultural Reviews
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/27/2017
Publication Date: 11/1/2017
Citation: Marini, R., Fazio, G. 2017. Apple rootstocks: history, physiology, management and breeding. Horticultural Reviews. 78:197-312.

Interpretive Summary: This review article describes the history and role of apple rootstocks in apple production. For more than two millennia superior apple varieties have been grafted onto rootstocks to maintain the genetic identity of the desirable variety also known as the scion. Until the 20th century most fruit trees were grafted onto seedling rootstocks. Following the classification, evaluation and propagation of clonal rootstocks in the early 1900s, dwarfing rootstocks became important to the commercial apple industries. Trees on dwarfing rootstocks are more economical to maintain, and are more precocious and productive than trees on seedling rootstocks, but there remains a need for dwarfing rootstocks adapted to different growing conditions. In the past 100 years considerable effort has been made to understand the physiological changes in the scion induced by rootstocks. More recently molecular techniques have been utilized to identify the genes that control interactions between scion and rootstock. Modern rootstock breeding programs are combining molecular and traditional techniques to develop rootstocks that are dwarfing, productive, and tolerant to biotic and abiotic stresses. We discuss the history, development and current use of apple rootstocks, our current understanding of rootstock × scion interactions, and current efforts to develop and evaluate superior rootstocks.

Technical Abstract: For more than two millennia superior fruit tree genotypes have been grafted onto rootstocks to maintain the genetic identity of the desirable scions. Until the 20th century most fruit trees were grafted onto seedling rootstocks. Following the classification, evaluation and propagation of clonal rootstocks in the early 1900s, dwarfing rootstocks became important to the commercial apple industries. Trees on dwarfing rootstocks are more economical to maintain, and are more precocious and productive than trees on seedling rootstocks, but there remains a need for dwarfing rootstocks adapted to different growing conditions. In the past 100 years considerable effort has been made to understand the physiological changes in the scion induced by rootstocks. More recently molecular techniques have been utilized to identify the genes that control interactions between scion and rootstock. Modern rootstock breeding programs are combining molecular and traditional techniques to develop rootstocks that are dwarfing, productive, and tolerant to biotic and abiotic stresses. In this review, we discuss the history, development and current use of apple rootstocks, our current understanding of rootstock × scion interactions, and current efforts to develop and evaluate superior rootstocks.