Submitted to: Blueberry Research Extension North American Workers Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 5/27/1998
Publication Date: N/A
Technical Abstract: We are progressing toward our goal of mapping quantitative trait loci (QTLs) controlling chilling requirement and cold hardiness in blueberry. Randomly amplified polymorphic DNA (RAPD)-based genetic linkage maps are being constructed using two testcross populations segregating for chilling requirement and cold hardiness. Testcross populations were derived from interspecific hybrids of wild diploid blueberry species, Vaccinium darrowi Camp x V. caesariense Mackenz. Twenty-seven RAPD markers were assigned to eight linkage groups in the V. darrowi testcross and 37 RAPD markers were assigned to 12 linkage groups in the V. caesariens testcross. Chilling requirement data was used in a generation means analysis to evaluate different genetic models to explain the gene action of chilling requirement. This analysis, which assumes that parental populations are homozygous for all genes controlling chilling requirement, failed to identify any models which accurately described the chilling requirement gene action for the populations analyzed. Based on the observed segregation ratios of chilling requirement in the F1 and testcross populations, we were able to evaluate single and digenic models for the inheritance of chilling requirement. A two gene model was developed which fairly accurately predicted the observed ratios in the testcross populations. In its simplest form, this model assumes that two genes with equal and additive effects control chilling requirement.