Tolerance of Acacia populations following inoculation with the Ceratocystis canker and wilt pathogen in Vietnam

Inoculations of two Acacia populations were used to estimate the level of genetic control for tolerance to Ceratocystis canker and wilt disease following inoculation with the causal pathogen, Ceratocystis manginecans . The first screening utilised a range of clones commonly established in Vietnam along with new candidate clones and provided evidence that variation in wilt symptoms is under a moderate level of genetic control in current deployment populations. Subsequent assessments of tolerance in a pedigreed Acacia auriculiformis progeny trial indicated that internal lesion length assessments were less influenced by seedling height and produced higher heritability estimates than external lesion length assessments. Heritability estimates for damage to detached phyllodes following inoculation increased from 2 to 4 weeks, at which point many leaves were entirely damaged. Assessments of phyllode damage were more heritable than assessments of stem damage, and positive genetic correlations between stems and phyllode damage indicate that families will rank similarly for both traits. If validation trials confirm the results of this study in larger trees, screening as described herein may be used to develop acacia breeds with greater disease tolerance.