Time of seed harvest and sowing determines successful establishment of kangaroo grass (Themeda triandra) on Dja Dja Wurrung Country

Context Kangaroo grass (Themeda triandra Forssk.) is a native perennial C4 species significant to Dja Dja Wurrung people who seek to restore its presence across Country (Djandak) through broadacre seed crop production. To achieve this, agronomic challenges to establishment must be overcome. Aims To understand the effects of harvest time on seed viability and sowing time on crop establishment. Methods In Experiment 1, seed viability was assessed in a remnant Djandak stand in three seasons and seed colour assessed and cumulative seed shed measured in two of these seasons. In Experiment 2, seed from two Djandak ecotypes was sown at two sites at eight sowing dates over two seasons and plant emergence, culm number and canopy cover were recorded. Key results In Experiment 1, seed was shed from mid-December to late-January and seed viability varied intra- and inter-seasonally. Viability of early shed seed was low (0–24%) but increased with time to a peak of 68–69% in the first two seasons and 28–37% in the final season. Most seed had shed when peak viability was reached. Dark-coloured seeds with a caryopsis exhibited both high viability and high dormancy. In Experiment 2, sowing in September–October resulted in the optimal combination of highest mean establishment, lowest variability and no establishment failures. Conclusions To maximise crop establishment, seed should be sown in September–October on Djandak and be harvested when 30–50% of seed has shed. Implications These guidelines inform T. triandra establishment supportive of its development as a broadacre seed crop.