Progress Toward Identifying Markers Linked to Genes Controlling Chilling Requirement and Cold Hardiness in Blueberry

Progress was made in identifying molecular markers linked to genes which control chilling requirement and cold hardiness in a woody perennial, blueberry (Vaccinium, section Cyanococcus). Construction of RAPD (randomly amplified polymorphic DNA)-based genetic linkage maps using two testcross populations derived from interspecific hybrids of wild diploid blueberry species, V. darrowi Camp X V. eliiottii Chapm. and K darrowi X V. caesariense Mackenz. was continued. Mapping populations were segregating for chilling requirement and cold hardiness. Screening plants of the V. darrowi x V. eaesariense-aenvea mapping population for cold acclimation capacity using leaf tissue collected before and after cold treatment and an electrolyte leakage assay was begun. In addition, a tetraploid breeding population (predominantly V. corymbosum L.) was screened for chilling requirement and efforts were begun to identify markers linked to genes determining chilling requirement using this population and a bulked-segregant-type analysis.