ABSTRACT
Summary Most summer forage crops fall into either the sorghum or the millet species group. Included in the millet group are two species, Echinochloa utilis and Echinochloa frumentacea, commonly known as Japanese barnyard millet and Indian barnyard millet, respectively. These species have a negligible HGN potential and higher nutritive value than Sorghum species. However, they generally flower early, yield less than forage sorghum, and lack vigor in regrowth. In this study the pattern of growth and development of two Echinochloa millets was examined as part of a larger program of improving the production of these forage species. E. utilis cv. Shirohie and E. frumentacea cv. White panicum were grown under surface irrigation at Trangie (lat 32°S long 148°E). Mean weekly maximum and minimum temperatures ranged from 37° 123° C to 28°/14° C during the growing period. Uninterrupted growth was measured by sampling every 2 weeks; regrowth from sampled areas was measured at the end of the growing season. Leaf area was determined, and the dried plant fractions were weighed and analyzed for nitrogen, sodium, and sulfur. The maximum growth rate and dry-matter yield of E. utilis (30 g/m2/day and 11.7 tonnes/ha, respectively) were greater than those of E. frumentacea (11 g/m2/day and 5.9 tonnes/ha, respectively). Morphological features including a prostrate growth habit and smaller leaf size were associated with the low yields of E. frumentacea. Late flowering in E. frumentacea (20 days later than E. utilis) indicated delayed elevation of the apical meristem; regrowth was better in this species. When the extent of tiller decapitation was equivalent in the two species, regrowth yields were similar. To obtain good regrowth, it is necessary to cut or graze a crop of E. utilis before 7 weeks. Alternatively, regrowth may be improved by otaining cultivars that flower later and/or tiller more extensively. E. utilis was higher in sodium and sulfur than E. frumentacea; nitrogen contents were similar. Mineral concentrations changed with time and, especially with sodium, differed between plant parts. For both species, mineral levels exceeded animal requirements, although the N/S ratio for E. frumentacea was marginal. Important agronomic differences between the two Echinochloa millets have been elucidated. The characterization of growth and development has demonstrated how high forage yields in these nutritionally desirable species may be obtained.
