Impact of inbreeding on growth and development of young open-pollinated progeny of Eucalyptus globulus

The use of open-pollinated seeds from seed orchards is a common strategy for the deployment genetically improved eucalypts, including Eucalyptus globulus, an important pulpwood tree in many temperate climate areas. However, quality can be affected by rate selfing and to lesser extent contamination pollen outside orchard. Inbreeding between related parents especially self-crosses known cause diminished growth developmental abnormalities resulting progeny. This study looks at magnitude variation impact inbreeding depression across several E. globulus families collected over years effects on development outcrossed selfed progeny were studied five trials, after pedigree reconstruction open pollinated based SSR genotyping. An additive genetic mixed linear model was fitted data evaluate height growth. results showed significant depression, with reduction 15% progeny, when compared crosses unrelated parents. These values varied among families, ranging 7% 24%, evidencing importance background. Contamination rates average 10% suggesting long distance dispersal present. A small number abnormal phenotypes (less than 10%) observed field. associated specific, unrelated, not high such as found relevance these orchard management parent selection discussed.