Articles
History and new releases from the Geneva® apple rootstock breeding program
Article number
1457_7
Pages
49 – 62
Language
English
Abstract
The Geneva® apple rootstock breeding program has been operating at Cornell University since the late 1960s, with the main goal to develop new material resistant to pests and diseases endemic to North America.
The US. Department of Agriculture joined this effort in the late 1990s, leveraging the field, laboratory, technical, and germplasm resources the program had, and adding a major component focused on genetics, genomics, and marker-assisted breeding.
The project has maintained the focus on resistance to fire blight, crown, and root rot while evaluating material for increases in orchard productivity.
The program also worked with external national and international institutions, such as the NC-140 rootstock evaluation collaborative group, to test its products in multiple environments.
The process, which for some apple rootstocks has spanned 3-4 decades from initial cross to final release, has produced several rootstocks including G.11, G.16, G.41, G.935, G.214, G.814, G.778, G.222, G.213, G.210, G.969, G.890. Each of these rootstocks has displayed outstanding properties as well as some shortcomings.
While breeding, the program made discoveries about the nature of dwarfing, early bearing, and the rootstock’s propensity to influence the partitioning of photosynthate away from excessive vegetative growth and into fruit production.
More recently, the program has made discoveries on additional traits that modulate fruit quality (fruit size and nutrient content), tree architecture, influence on chilling hour requirement, graft union strength, brittle or malformed graft unions, root morphology and metabolic compounds, phytohormone influence on grafted scions, interaction with woolly apple aphids, interaction of rootstocks with multi-leader training systems, and interaction with soil properties (pH and composition). As we learned more about each of the Geneva® rootstocks, it has become clear that the observed diversity in traits is an asset to the diverse applications/environments representing apple orchards worldwide.
Each orchard is unique in its soil and climate characteristics, and this, combined with different scion cultivar characteristics and vigor, means that no one rootstock is the best choice in all situations.
This awareness leads the program to continue pursuing new rootstocks that are better in certain niche situations than all other rootstocks.
All these considerations, in addition to new nursery and field performance results, have led the Geneva® apple rootstock breeding program to release three new rootstocks: Geneva® 257 (G.257), Geneva® (G.484), and Geneva® (G.66).
The US. Department of Agriculture joined this effort in the late 1990s, leveraging the field, laboratory, technical, and germplasm resources the program had, and adding a major component focused on genetics, genomics, and marker-assisted breeding.
The project has maintained the focus on resistance to fire blight, crown, and root rot while evaluating material for increases in orchard productivity.
The program also worked with external national and international institutions, such as the NC-140 rootstock evaluation collaborative group, to test its products in multiple environments.
The process, which for some apple rootstocks has spanned 3-4 decades from initial cross to final release, has produced several rootstocks including G.11, G.16, G.41, G.935, G.214, G.814, G.778, G.222, G.213, G.210, G.969, G.890. Each of these rootstocks has displayed outstanding properties as well as some shortcomings.
While breeding, the program made discoveries about the nature of dwarfing, early bearing, and the rootstock’s propensity to influence the partitioning of photosynthate away from excessive vegetative growth and into fruit production.
More recently, the program has made discoveries on additional traits that modulate fruit quality (fruit size and nutrient content), tree architecture, influence on chilling hour requirement, graft union strength, brittle or malformed graft unions, root morphology and metabolic compounds, phytohormone influence on grafted scions, interaction with woolly apple aphids, interaction of rootstocks with multi-leader training systems, and interaction with soil properties (pH and composition). As we learned more about each of the Geneva® rootstocks, it has become clear that the observed diversity in traits is an asset to the diverse applications/environments representing apple orchards worldwide.
Each orchard is unique in its soil and climate characteristics, and this, combined with different scion cultivar characteristics and vigor, means that no one rootstock is the best choice in all situations.
This awareness leads the program to continue pursuing new rootstocks that are better in certain niche situations than all other rootstocks.
All these considerations, in addition to new nursery and field performance results, have led the Geneva® apple rootstock breeding program to release three new rootstocks: Geneva® 257 (G.257), Geneva® (G.484), and Geneva® (G.66).
Publication
Authors
G. Fazio, T.L. Robinson
Keywords
apple rootstock, fire blight resistance, semi-dwarfing, yield efficiency, fruit size, mineral nutrient profile
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