Genetically Based Resistance of<i>Eucalyptus marginata</i>to<i>Phytophthora cinnamomi</i>

Sixteen half-sib families of jarrah (Eucalyptus marginata) seedlings were screened for resistance to Phytophthora cinnamomi using soil inoculation and stem inoculation in pot experiments, and soil inoculation in a P. cinnamomi-infested field site. Low mortality following soil inoculation and short lesion lengths following stem inoculation were used as indicators of P. cinnamomi resistance. Resistance levels varied continuously across families from high to low values in all experiments, but family rankings were consistent among experiments. The narrow-sense heritability of the resistance character was high at both family (0.74-0.85) and individual-tree (0.43) levels. The resistance of jarrah to P. cinnamomi is under strong genetic control [...]