Is there a negative genetic correlation between initiation of embryogenic tissue and fungus susceptibility in Norway spruce?

Genetic associations between initiation of embryogenic tissue (ET) and susc eptibility to the phytopathogenic fungi Ceratocystis polonica (Siem.) C. Mo reau and Heterobasidion annosum (Fr.) Bref. in Norway spruce have been stud ied by initiating ET from zygotic embryos of mature seeds collected from 19 clones tested for susceptibility to the pathogens in a clonal field trial. Initiation frequencies varied significantly among clones (families), rangi ng from 12 to 56%. The family variance component accounted for more than 40 % of the total variance in initiation frequency of ET. The estimates of bro ad-sense heritability of fungus susceptibility of the clones ranged from 0. 12 for length of phloem necrosis after low-density inoculation with H. anno sum to 0.55 for blue-stained sapwood after mass inoculation with C. polonic a. None of the susceptibility measures showed any phenotypic correlation wi th initiation of embryogenic tissue. Genetic correlations and their standar d errors were estimated by bootstrapping. Two measures of fungal susceptibi lity correlated genetically with initiation of ET; estimated at -0.58 for l esion length after inoculation with C. polonica and -0.29 for H. annosum le sion length. A better measure of susceptibility, blue-stained sapwood follo wing inoculation with C. polonica, was not correlated with initiation of ET .