Height growth and survival of within- and between-provenance crosses in jack pine

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Abstract
Controlled pollinations with provenances from Petawawa (Ontario), Fife Lake (Michigan), and Big River (Saskatchewan) were made in all possible combinations, with the ensuing offspring planted at three sites along a north-south transect in Ontario. Survival at age 8 decreased with increased boreal character at the site. Survival of provenance hybrids was intermediate to that of their intraprovenance counterparts. Statistically significant heterosis (departure from midvalue of associated intraprovenance performances) was observed in tree height at two locations. At the northern-most site, growth was poor, with no significant differentiation among any of the tested full-sib families. Within-block microsite quality was unevenly distributed at two sites, which resulted in a low blocking efficiency and a highly significant among-plot variation. However, with five full-sib families per provenance cross, the impact on the statistical analysis of crosses was negligible.