Clonal variation in cone and seed production in black and white spruce seed orchards and management implications

Variation in cone and seed production across a range of clones in black and white spruce seed orchards was investigated in 1994. The purpose was to develop production information to be used with knowledge of orchard management practices to capture genetic gain more efficiently and improve clonal balance in orchard seedlots. Bulk cone collections were made from ten randomly selected trees for each of 48 clones and 60 clones of white spruce and black spruce, respectively. The average number of cones tree(-1) was determined for each clone. Seeds were extracted and average seeds tree(-1), seeds cone(-1) and seeds g(-1) were determined for each clone. Clones were ranked by cone and seed production and significant variation existed between the two ranks. For white spruce, a strong positive correlation was found between number of cones tree(-1) and number of seeds, but the same was not found for black spruce, largely because some of the heaviest cone bearing clones produced lower amounts of sound seed. For both species, clones which produced more cones tree(-1) tended to produce fewer seeds per cone and the seed was smaller than clones with more moderate levels of cone production. Clonal balance in cone and seed production is discussed with respect to practical orchard management options.