Author
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Myers, Clayton |
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Submitted to: Newsletter of the Midwestern Apple Improvement Association
Publication Type: Popular Publication Publication Acceptance Date: 7/1/2007 Publication Date: 8/1/2007 Citation: Myers, C.T. 2007. Searching for apples even a bug can't stomach: insect resistance in Malus germplasm. Newsletter of the Midwestern Apple Improvement Association. 9(1): 9-10. Interpretive Summary: Technical Abstract: Research is currently being conducted to observe and evaluate both domestic and exotic Malus germplasm for the occurrence of host-plant resistance to major apple pests, including plum curculio, obliquebanded leafroller, apple maggot, oriental fruit moth, and codling moth. Collections being evaluated include a number of disease resistant apple hybrid selections previously released from the Purdue-Rutgers-Illinois (PRI) breeding program, several of which were released with claims of insect pest resistance. Additionally, exotic germplasm representing nearly 90 percent of the known genetic diversity within Malus was evaluated for pest resistance. While some significant differences in feeding and/or oviposition preferences were observed, there was no true resistance exhibited among any germplasm to attack from plum curculio or obliquebanded leafroller, even among selections that were previously described as resistant. A number of accessions previously reported to be resistant to attack from apple maggot and plum curculio were also shown to be quite susceptible to attack from these pests. One hybrid selection was demonstrated to be quite resistant to larval feeding by apple maggot until very late in the season and evidence indicates that factors beyond fruit maturity are likely contributing to this observed resistance. Two crabapple species were shown to be resistant to larval feeding by codling moth and oriental fruit moth. Future research will focus on the mechanisms of this observed resistance, on the phytochemical variation among Malus accessions, and eventually the underlying genetics controlling the expression of such resistance. |
