Variation in seed yield and its components in the Australian native grass Microlaena stipoides as a guide to its potential as a perennial grain crop

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 long-standing 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, 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 20-fold range in seed yield (0.1-2.4 g/plant), 5-fold range in seed weight (129-666 mg per 100 seeds), 2-fold range in spikelet number (14-30 per culm), 8-fold range in seed set (12-98%), and a 5-fold range in culm number (11-59 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 that 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. High priority traits for future work include synchronous maturity and resistance to shattering.