Variation and Natural Heritability of Blueberry Floral Volatiles

Vaccinium corymbosum (highbushblueberry)in British Columbia relies on honeybee pollination for a reliablefruit set. As floral volatiles may help explain pollinator preferencefor blueberry, we surveyed components of variation for volatiles usinggas chromatography-mass spectrometry (GC/MS). Principal componentanalysis of GC chromatogram peaks revealed a grouping of cultivarsby a biosynthetic pathway that also corresponds with their known pedigree.To identify genetic variance, we identified 34 chemicals with adequatesample sizes. We estimated "natural heritability" (usinguncontrolled crosses in natural environments) in two ways: (1) as"clonal repeatability," which is equivalent to broad-senseheritability and is an upper bound for narrow-sense heritability,and (2) "marker-based heritability," which serves asa lower bound for narrow-sense heritability. Both methods indicatethat heritability is relatively low, ca. 15%, and variable among traits.This is expected as the floral volatile release is changeable anddependent on environmental conditions. It might be possible to usehighly heritable volatiles for breeding.