GENETIC AND PHENOTYPIC RELATIONSHIPS BETWEEN WEEVIL (PISSODES STROBI)RESISTANCE AND HEIGHT GROWTH IN SPRUCE POPULATIONS OF BRITISH-COLUMBIA

Strong genetic differences were demonstrated for both resistance to wh ite pine weeuil (Pissodes strobi (Peck)) attack and juvenile height gr owth in an open-pollinated progeny test of interior spruce. This test was a large (139 families) 10-year-old test in south central British C olumbia with 8 years of accumulated weevil attack individual-tree heri tability for genetic resistance was congruent to 0.4, Strong differenc es among families for this resistance was shown by a coefficient of va riation of 46%. Besides strong family effects, the source of origin of parent trees, as indicated by biogeoclimatic zone, was a significant effect in the model. Individual-tree heritability was also high for ju venile height growth (congruent to 0.5). Although there is a significa nt positive phenotypic correlation (r(p) = 0.11) between leader growth and weevil attack (the weevils preferring longer leaders), there is a strong negative genetic correlation (r(A) = -0.61) indicating that in herently faster growing families have higher levels of genetic resista nce. This high and favorable negative genetic correlation is accompani ed by a positive environmental correlation of the same magnitude (r(E) = 0.46), indicating that environmental effects, which make longer lea ders more attractive to the weevils, are independent of the fact that more vigorous families are more likely to have effective resistance to weevil attack.