Identification of pre-zygotic reproductive and morphological barriers limiting controlled crossed seed production of triploid Acacia mearnsii

► To produce a 3n black wattle, one can use a 2n or 4n maternal parent. ► With a 4n maternal parent, pollination and ovary fertilisation rates were greater. ► The only barrier limiting seed production was within the ovary. ► Tetraploid floral parts were significantly larger than the diploids. ► The morphological size differences did not influence fertilisation of the ovaries.