1a. Objectives (from AD-416):
The overall research goal is to identify QTL associated with chilling requirement, cold tolerance, and various fruit quality traits in the tetraploid highbush blueberry (V. corymbosum) mapping population developed by Michigan State University.
1b. Approach (from AD-416):
A tetraploid highbush blueberry (V. corymbosum) mapping population, derived from a cross between the northern highbush cultivar ‘Draper’ and the southern highbush cultivar ‘Jewel’, will be used for identifying QTL associated with chilling requirement, cold tolerance, and various fruit quality traits. The population will be propagated, planted, and evaluated for these traits at various locations, including Florida, Georgia, Oregon, and Michigan, over two years. EST-SSR and EST-PCR markers will be developed from blueberry ESTs and added to the current map of this population. QTL associated with chilling requirement, cold tolerance, and various fruit quality traits will be identified using appropriate software designed for mapping quantitative traits in tetraploid populations.
3. Progress Report:
The purpose of this agreement was to distribute part of the funds from a CSREES-funded Specialty Crop Research Initiative (SCRI) project entitled “Generating Genomic Tools for Blueberry Improvement” to the Co-PI at Michigan State University. Genomic resources for genetic improvement are lacking in blueberry. The objectives of this project were to add molecular markers to a genetic linkage map of blueberry and identify markers in this breeding population associated with cold hardiness, chilling requirement, and various fruit quality traits. The tetraploid mapping population was established at five locations with varying winter temperatures and chilling hours: Gainesville, FL; Waycross, GA; Invergowrie, Scotland; Corvallis, OR; and Benton Harbor, MI. Plants at the various field locations were evaluated first in 2011 for many traits including timing of flower and leaf bud break, extent of vegetative development, timing of bloom, fruit color, fruit firmness, soluble solids, titratable acidity, yield, and total anthocyanins, among others. Potted plants of the mapping population were also evaluated for chilling requirement at Michigan State University in 2011. Plants are currently being evaluated for the second year (2012). Preliminary QTL analyses based on 2011 data from the Florida and Georgia locations identified significant QTL for almost all the evaluated traits. This project relates to the in-house parent project, objective 3, identifying germplasm and developing molecular markers and genetic maps useful for conferring traits of horticultural value, such as cold tolerance in blueberry, disease resistance in strawberry, and repeat flowering in strawberry, raspberry, and blackberry. Ultimately, this research will be used by blueberry breeders to develop new, improved blueberry varieties through marker-assisted selection.