Themeda triandra as a perennial seed crop in south-eastern Australia: What are the agronomic possibilities and constraints, and future research needs?

Figures & data

Figure 1. A map of the Dja Dja wurrung recognition and settlement agreement area in central Victoria, Australia (approx. 36°06ʹ S to 37°30ʹ S; 142°58ʹ E to 144°41ʹ E). Source: Karina Pelling, accessed in March 2022 from the Australian National University.

Figure 2. A young ~16-month-old) T. triandra tussock in April 2022 on Dja Dja Wurrung country near Dean, Victoria (37°27ʹ S 144°00ʹ E). Photo contributed by Dylan Male.

Figure 3. A line diagram of a T. triandra tussock, panicle, spikelet, and seed diaspore morphology. Source:Gardner (1952).

Figure 4. T. triandra seed diaspore (left); T. triandra naked caryopsis (right).Note: Seed length varies, generally <5 mm. Figure contributed by Dylan Male.

Table 1. A summarised morphological description of T. triandra (Martin, 1975; Mitchell & Wilcox, 1994; Wheaton, 1994; Tainton & Booysen, 1965; Morgan, 1999; Mitchell, 2001; Snyman et al., 2013; Australian National Botanic Gardens. Centre for Australian National Biodiversity Research, 2016; Godfree et al., 2017; Ghebrehiwot et al., 2006; Ibrahim et al., 2018; Cavanagh et al., 2019)

Plant part	Description
Overall structure	Tufted perennial tussock growing up to 0.5 m wide and 2.0 m tall. Immature foliage is blue-green and matures to reddish-brown with distinctive spikelets.
Leaf	Basal and cauline; blades 0.1–0.5 m long and 2–5 mm wide.
Tillers	Asynchronous primary and secondary tillers that can develop into reproductive tillers (culms) 0.3–2.0 m tall.
Inflorescence	Consists of a panicle 0.1−0.3 m long with a variable number of spikelet clusters. Each cluster consists of one or two bisexual unifloret spikelets and six or more male unifloret spikelets.
Spikelet	Spikelets in groups of 7; 4 paired sterile basal spikelets and a triplet of 2 pedicelled spikelets and 1 fertile spikelet. Fertile spikelets 6–11 mm long.
Seed diaspore	Seed is dark in colour and has a sharp callus at the base tipped with stiff hairs. Naked caryopsis is slender, cream in colour, 2–3 mm long. Awns are 25–70 mm long, twisted and dark in colour.
Roots	Fibrous roots grow from basal nodes found on primary tillers and are concentrated in the top 0.3 m of soil. Rooting depth dependent on soil type, at least 1 m. Highly variable root to shoot ratio, and root mass has the potential to be greater than shoot mass.

Figure 5. The annual development cycle of a T. triandra stand relative to the months of the year on Dja Dja Wurrung country, Victoria, Australia. Figure illustrated by Dylan Male.

Figure 6. An uncleaned seed lot containing stem, spikelet, and seed diaspore material, harvested from a brush harvester. Photo contributed by Dylan Male.

Figure 7. The hypothesised first-year development of a dryland T. triandra seed crop relative to months of the year on Dja Dja Wurrung country, Victoria, Australia. Figure illustrated by Dylan Male.

Figure 8. Harvest of T. triandra seed using a brush harvester. Photo contributed by Dylan Male.

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Data Availability Statement

There were no data generated by this review.