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Perennial Grain Crops for High Water Use - The case for Microlaena stipoides by CL Davies, DL Waugh and EC Lefroy
February 2005
RIRDC Publication No 05/024 RIRDC Project No UWA 60A
This research investigated the potential to domesticate an Australian native grass (Microlaena stipoides) to produce a perennial grain crop. Perennial grain crops offer a new solution to the longstanding problems of salinity and soil erosion associated with conventional cropping systems based on annual plants.
Seed yield and its components (culm number, spikelet number per culm, seed set and seed weight) were measured in 46 accessions of Microlaena stipoides (microlaena, meadow or weeping rice grass) from Western Australia and New South Wales to quantify potentially useful variation in the species.
A high degree of variability was found to exist, with a twenty-fold range in seed yield (0.1 to 2.4 g/plant), five-fold range in seed weight (129 to 666 mg per 100 seeds), two-fold range in spikelet number (14 to 30 per culm), eight-fold range in seed set (12 to 98%) and a five-fold range in culm number (11 to 59 per plant). Seed yield was positively and significantly (P<0.05) correlated with culm number, seed set and seed weight (r>0.55 for all). No correlation was found between seed yield and spikelet number per culm (r=-0.14).
The range in seed yield and its components suggests there is sufficient variation within microlaena to make selections for higher yielding lines. This variation will enable breeders to exploit genetic diversity more efficiently and identify useful accessions for further work. This study evaluated the variation in components of seed yield at only one site. The next step should be to evaluate superior lines at multiple sites across Australia.
While it is unlikely that grain yields in microlaena will be comparable with those of annual grains, it is possible that a dual value as a grain and grazing crop could help to offset lower returns from seed harvest. Other favourable characteristics such as synchronous maturity and resistance to shattering need to be considered.
Continued consideration of Microlaena stipoides as an alternative perennial grain crop requires evaluation of the compositional and nutritional characteristics of its grain to determine its suitability for use in food products for human consumption and stock feed. Of particular interest are its starch composition and, because it is fairly closely related to rice, its likely gluten-free status.
 
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