Fine-scale Spatial Genetic Structure Associated with Vaccinium angustifolium Aiton (Ericaceae)

This study tested, at the within the field scale, if a positive fine-scale spatial genetic structure (FSGS) in lowbush blueberry could be detected. Using a contiguous design (all touching clones within 0.35 ha of one field) and a “neighbourhood” design (a few focal clones in two fields surrounded by their touching neighbour clones) we found, using EST-PCR (Expressed Sequence Tag-Polymerase Chain Reaction) markers, through non-parametric, distance based methods, significant positive spatial autocorrelation (SA) within the first distance class of 7.5 m (r = 0.067 + 0.022; P > 0.001). Two-dimensional local spatial autocorrelation revealed in both designs significant, positive SA in clusters of clones. Particularly, in the contiguous design, 32 of the 94 clones were found within the genetic similarity range of 0.53 – 0.72 (the range expected with dominant markers for half to full-sib relationships (0.65 – 0.80)). These related clusters displayed a patchy architecture interspersed with the balance of clones following a random distribution. In the “neighbourhood” design, AMOVA revealed significant between-field (Φpt = 1.6%) and within-field (Φpr = 3.7%) genetic differentiation. Two possible evolutionary hypotheses are discussed that render insight into the dynamics of how these fields developed and how the high levels of genetic diversity are maintained.