Rapid identification of white-Engelmann spruce species by RAPD markers.

Fragments of random amplified polymorphic DNA (RAPDs) were used as markers to distinguish Picea glauca (Moench) Voss (white spruce) and Picea engelmannii Parry (Engelmann spruce). These species and their putative hybrids are difficult to differentiate morphologically and are collectively known as interior spruce. Four oligodeoxynucleotide decamer primers showed species-specific amplification products between white spruce and Engelmann spruce. These fragments are highly conserved among seed lots and individual trees of each species from diverse geographic origins. The consistency and reproducibility of these species-specific amplification products were tested in more than two amplification reactions. Therefore, RAPD markers can provide genetic markers for easy and rapid identification of the specific genetic entry of these spruce species and their reported putative hybrids. According to the frequencies of the species-specific RAPD markers, it is possible to estimate the hybrid fraction, indicative of true introgression between the two species. These results are useful for quick identification of both species and their hybrid swarms at any stage in the sporophyte phase of the life cycle, for determining the occurrence and the magnitude of introgressive hybridization in an overlap zone between the two species, and for certification purposes in operational re-forestation and tree-improvement programs.