Project Number: 8080-21000-026-01-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Oct 1, 2014
End Date: Aug 31, 2019
The objectives for this project are: 1) derive valuable alleles for disease resistance from exotic genepools for integrated cultivar and rootstock breeding to mitigate production risk and 2) enrich breeding families with alleles for superior fruit quality combined with disease resistance to provide the next generation of superior cultivars.
Pedigree-linked germplasm that contains resistance alleles for the target disease threats (fire blight, apple scab, and blue mold) coming from exotic gene pools were previously crossed to important breeding parents. ARS scientists will identify sets of existing pedigree-linked germplasm segregating for disease resistance, where either the genetic control of the resistance is unknown or the previously discovered resistance alleles have not yet been validated in a breeding germplasm background. For apple (Norelli), three sets will be established: Apple Scab Set, Apple Fire Blight Set, and Apple Blue Mold Set. ARS scientists will make crosses among donor germplasm sources and with elite breeding parents to pyramid alleles that confer disease resistance. This may be to pyramid alleles for just one disease threat or to pyramid the desired alleles for more than one disease threat. The progeny from these parental pools will be genotyped for the desired resistance QTLs/M-L-T associations using DNA tests. A set of those individuals that contain the desired disease resistance alleles will be selected as parents for use in the next round of crosses. If the progeny used to pyramid the disease resistance alleles are also predicted to segregate for major fruit quality loci, the progeny will be subjected genetic tests for fruit quality alleles prior to parental selection.